- 1

©Paragon Industries, L.P. IM-205/8-04

Trouble Shooterfor the Sentry

Controller

2

3

4

5

6

2

43

5

6

1

Wiring for Omron & Arowmat Relays

1 Wiring for P & B Relay

Relay Conversion ChartSometimes a replacement relay will be of a different brand than the relay in

your kiln. If so, transfer the wires from the old relay to the new one by the num-bers on this chart. Ignore the terminal numbers printed on the relay bodieswhen referring to the numbers on this chart.

Static electricity can damage the controller.Before handling the board, touch a groundedobject. When shipping the controller forrepairs, do not pack in bubble wrap or styro-foam peanuts. These materials can build up astatic charge. Instead, use anti-static foam oreven newspaper.

DisconnectPower before

removingcontroller and

switch box.

Wires from Controller

Wires from Controller

Ramp-Hold& Cone-FireVersion

Ramp-HoldVersion

2 -

- 3

Contents

Electrical Power ProblemsController display does NOT turn on. No heat in kiln. . . . . . . . . 4Controller display turns on. No heat in kiln. . . . . . . . . . . . . . . . . 5Kiln fires too slowly or will not reach temperature. . . . . . . . . . . . 6Some elements do not fire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Kiln heats unevenly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Circuit breaker trips or circuit fuse blows.. . . . . . . . . . . . . . . . . . 9Kiln switch box high amperage fuse blows. . . . . . . . . . . . . . . . . 9Kiln switch box ½ amp fuses keep blowing.. . . . . . . . . . . . . . . . 9Wall outlet gets hot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Temperature, Display, and Keypad ProblemsController reads wrong temperature. . . . . . . . . . . . . . . . . . . . . 10The kiln overfires.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11The display shows erratic temperature readings. . . . . . . . . . . . 12The display remains stuck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Display digits burned out (parts of display missing). . . . . . . . . 12The “1” and/or the “4” key does not respond. . . . . . . . . . . . . . 13Ramp-Hold target temperature shown in Program Review islower than the temperature you programmed. . . . . . . . . . . . . . 13

NoisesThe relay chatters or buzzes. . . . . . . . . . . . . . . . . . . . . . . . . . . 13The controller keeps beeping.. . . . . . . . . . . . . . . . . . . . . . . . . . 13

Error MessagesBAdP / Bad Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13ETH / Electronics Too Hot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13FAIL / Thermocouple Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . 14FTC / Failed to Cool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14FTH / Failed to Heat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14FTL / Firing Too Long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14HTdE / High Temperature Deviation . . . . . . . . . . . . . . . . . . . . . 15The “LId” Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15LTdE / Low Temperature Deviation . . . . . . . . . . . . . . . . . . . . . . 15PF, PF 2 or PF 3 during firing. . . . . . . . . . . . . . . . . . . . . . . . . . . 15PLOG Error Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16TCdE / Uneven Multiple Zone Temperatures . . . . . . . . . . . . . . 16TCR / Thermocouple Leads Reversed . . . . . . . . . . . . . . . . . . . 16

How to Removethe Controller

The controller iseasy to remove fromthe switch box. First,disconnect the power.(Certain componentson the back of the con-troller can be damagedif they touch agrounded object whilethe kiln is plugged in.)

Remove the 4 screws holding the controllerboard faceplate to the switch box. Lift faceplateout of box and let the board hang on the box withthe back of the board facing you.

How to Open the Kiln Switch BoxUNPLUG the kiln or disconnect the power.

Top-Loading KilnsDoes your kiln switch box have a support

arm on the side? Ifso, remove twoscrews from the topof the switch box.The box is hingedon the bottom andwill open forward. Ifyour kiln does nothave a support armon the side of the switch box, remove the screwson each side of the switch box. Gently removethe box from the kiln.

Front-Loading KilnsIf the switch box is mounted to the side of

the kiln, remove the screws holding the box.Gently lift the boxaway from the kiln.

When the con-troller is mountedunder the kiln, re-move the four screwsholding the control-ler in place. You cangain access to theelectrical components by removing a front, bot-tom, or back panel.

Reinstalling a Switch BoxAfter you have finished the kiln repair, ar-

range the switch box wires so that when theswitch box is placed against the kiln, no wiretouches an element connector or the kiln case.These get hot enough to eventually burn off wireinsulation. If your kiln includes wire nuts insidethe switch box, tuck them out of the way. Theymust not contact the kiln case or element con-nectors.

Trouble Shooting TestsWall Receptacle No-Load Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Switch Box ½ Amp Fuse Ohmmeter Test. . . . . . . . . . . . . . . . . . . . . 4Controller Power Input Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Element Ohmmeter Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Controller Power Output Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Door/Lid Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Receptacle Under Load Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Ammeter Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Element Glow Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Scorched Paper Element Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Kiln Switch Box High Amperage Fuse Test . . . . . . . . . . . . . . . . . . . 8Kiln Switch Box ½ Amp Fuse Power Test . . . . . . . . . . . . . . . . . . . . . 9Relay Coil Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Thermocouple Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Relay 12 Volt Battery Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Electrical components under a smallfront-loading kiln.

Disconnect power before removingthe board from the switch box.

Electrical PowerProblemsPROBLEM Controller displaydoes NOT turn on.No heat in kiln.Is the kiln connected to the power?Make sure the kiln is plugged in. If the kiln’s wall circuit in-cludes a power disconnect lever, make sure the lever is in theon position. Does your kiln have an on-off switch? If so, makesure the switch is turned on.

Has the circuit breaker trippedor has a fuse blown?Is power reaching the wall receptacle?Test with a voltmeter.Wall ReceptacleNo-Load TestThis test should be performedonly by an experienced repairperson. Touch only the plasticor rubber handle of the voltme-ter probes during this test. Donot remove the receptacle face-plate.

Follow the instructions thatcame with your voltmeter, setting it to the AC mode. Insertthe voltmeter probes in the receptacle’s two slotted, hot con-nections. You could also test the outlet with a voltage detec-tor, which is an inexpensive instrument with a light thatblinks when placed near a live wire or outlet.

Has the kiln switch box½ amp fuse blown?Switch Box ½ Amp Fuse Ohmmeter TestThe kiln’s ½ amp fuse is located in the switch box. Remove bypressing the fuseholder and turningcounter-clockwise halfa turn. Check the fuseby placing the probes ofan ohmmeter on theends of the fuse. If theohmmeter reads lessthan an ohm (digitalmeter) or reads 0 ohms(analog meter), thefuse is okay. If the read-ing is OPEN (digitalmeter) or infinity/noneedle movement (an-alog meter), the fuse isbad. Replacement fuse:

AGC 1/2 A 250V ACIf replacement kilnswitch box fuses keep blowing, see “Kiln switch box ½ ampfuses keep blowing,” page 9.

If you do not have an ohmmeter, visually inspect the fuse.You will see a thin strand of unbroken wire in a good fuse.The wire usually appears broken in a burned fuse, similar tothe broken filament in a lightbulb.

Is the controller receiving power? TestINPUTS with a voltmeter.Controller PowerInput TestMake sure the kiln is un-plugged, and remove the 4screws holding the controllerboard faceplate to the switchbox. Lift faceplate out of boxand let the board hang on thebox with the back of the boardfacing you. Plug the kiln backin. Touch voltmeter probes (inAC mode) to both power IN-PUT connections. These arethe white and orange wiresplugged into theback of the board.You will find themin the bottomconnector.

Do not let theback of theboard touch agrounded ob-ject. Make surethe voltmeter is

4 -

Be sure the power disconnectswitch is in the on position.

Know the location of the circuitbreaker panel. Label the breaker thatcontrols your kiln’s circuit.

Place voltmeter probes in the twoslotted, hot connections of the outlet.

Use an ohmmeter to test the switch box fuse.

The fuse holder is on the side of most kiln switchboxes. Even if the wire in the fuse looks okay, thefuse could still be bad. Check with an ohmmeter.

Disconnect power before removingthe board from the switch box.

Testing for voltage at the controller’s INPUT terminals.

in the AC mode when placing the probes on INPUT connec-tions. You should have 20 - 24 volts AC between the whiteand orange wires.

Controller Input Test Result: The controller is notgetting power.

UNPLUG kiln. Check theswitch box for disconnectedwires between the cord, trans-former, and controller. Alsocheck for any bare wires (whereinsulation has been damaged)touching the case. A short at a lidswitch or relay can cause a 0 volt-age reading at the transformer.

If wiring is okay, replace thetransformer.

Controller Input Test Result: The controller isgetting 20 - 24 volts AC.

If you find 20 - 24 volts, correct voltage is reaching the boardfrom the transformer. Since the board is not lighting up, it isprobably defective. Try turning off the power for ten seconds.The board may light up when you turn the power back on. If itdoes not light up, return the controller for repair or replace-ment.

Controller Input Test Result: The controller isgetting less than 20 volts AC.

Did you recently re-place the transformer?It may be wired for thewrong voltage. (Seetransformer diagramson the cover.) Lessthan 20 volts is notenough voltage tooperate the controller.To find out the cause oflow voltage, continuebelow:

The back of the boardis still facing you. Un-plug/disconnect thekiln. Remove the bottom plug from the back of the board.Touch a voltmeter probe to the white wire and the otherprobe to the orange wire. Plug the kiln back in.

Result: Voltage at disconnected INPUT wires is lessthan 20: There are two possible reasons: 1) Low voltage atthe wall receptacle; 2) defective transformer. If wall recepta-cle voltage is correct, replace the transformer.

Result: Voltage at disconnected INPUT wires is 20 - 24:The transformer is sending correct voltage to the controller.Yet when the input wires were connected to the controller,voltage was less than 20. This means the controller is drain-ing the voltage and is defective. Return the controller for re-pair or replacement.

PROBLEM Controller displayturns on. No heat in kiln.Is the relay making its normalclicking sound?Program the kiln to ramp to 500°F at a rate of 100°F per hour.Start the program.

Yes, the relay is clicking.Test the elements with an ohmmeter:

Element Ohmmeter TestUNPLUG kiln/disconnect the power. Open the kiln’sswitch box. Make sure the wires connecting the relays tothe elements are secure. If connections are okay, checkthe elements with an ohmmeter as follows:

Touch the ohmme-ter leads to the twoelement connectorsof each element.Where you place theleads should be freeof corrosion. Ano-needle-move-ment reading on ananalog meter, orOPEN on a digitalmeter, indicates abroken element.

If your elements arewired in parallel,temporarily discon-nect the lead wiresfrom one end of theelement you are testing. Hold element connector with pli-ers as you remove the screw. Be gentle to avoid breakingthe element. Do not disturb the screw holding the ele-ment, only the one holding the lead wires.

Rule of thumb: If both lead wires of an element connect toanother element, the elements are wired in parallel. Discon-nect the lead wire(s) from one end of the element you aretesting.

If the elements check out okay, perform the “Relay 12 VoltBattery Test,” page 15.

No, the relay is not clicking.We know the controller is receiving voltage, because the dis-play is lit. But the voltage from the transformer may be too lowto power the relays. Perform the “Controller Power InputTest,” page 4. If your controller passes the input test, per-form the “Controller Power Output Test”:

Controller Power Output TestIs the controller sending voltage to the relays? Test OUT-PUT with a voltmeter:

the kiln/disconnect the power. Remove the 4screws holding the controller board faceplate to the switch

- 5

The ohmmeter sends an electric current throughthe element. If the element is broken, the meterwill show an OPEN circuit.

Testing for voltage with voltmeter probes at thedisconnected INPUT wires (the white wire andorange wire).

The transformer.

box. Lift faceplate out ofbox and let the board hangon the outside of the boxwith the back of the boardfacing you. Then plug thekiln back in. Use theElement Test option. (Itappears as in thedisplay. See “Options” inthe Sentry operator’smanual.) The ElementTest option sends powerto the relays.

Put the voltmeter in DCmode. (It must be in DCmode when testing OUT-PUT voltage.) Touch probes to the OUTPUT connec-tions (red wire and black wire) for at least 12 seconds.The red and black wires are in the plug on the back ofthe controller near the top.

Output Test Result: No voltage at OUTPUT wires.The controller is not sending power to the relays. Return thecontroller for repair or replacement.

Output Test Result: 10 - 12 volts DC at OUTPUTwires.

The controller is sending correct voltage to the relays. Un-plug kiln/disconnect power. Remove the kiln switch box.Look for disconnected wires between the controller, relays,and elements. Check the wiring diagram to be sure wires areconnected to the correct terminals. Be sure connections aretight. If the wiring is okay, perform the “Relay 12 Volt BatteryTest,” page 15.

Does the kilnhave a door orlid switch?If the controller issending correct voltageto the relays, test thedoor or lid switch.

Door/Lid SwitchTestFirst , UNPLUGkiln/disconnect power.Remove door/lid switchcover. Place ohmmeterleads across the twoswitch terminals. Openand close the door. Youshould get no continu-ity when lid/door isopen. Replace or adjustthe switch if you get ano continuity readingwith the lid or doorclosed (no-needle-movement on an analog ohmmeter,OPEN reading on a digital meter).

PROBLEM Kiln fires too slowlyor will not reach temperature.Is your kiln model rated to fire hotenough for the ware?The Sentry will not fire hotter than the maximum tempera-ture rating of the kiln. That temperature is shown on thekiln’s electrical data plate and in the Sentry’s option.(See “Options” in the Sentry operator’s manual.)

Does kiln voltage match circuit voltage?Be sure your 240 volt kiln is not plugged into a 208 volt outlet,and vice versa.

Have you programmed an extended holdor Cone-Fire pre-heat?Check to see if you have programmed a long hold time thatprevents the kiln from firing hotter.

Cone-Fire mode: If you have inadvertently programmed apre-heat, the kiln will not heat past 200°F until pre-heat hasfired to completion.

Check wall outlet voltage with a voltmeterduring firing.Low voltage can double firing time. Sometimes voltage iscorrect, but drops when the kiln turns on.

Receptacle Under Load TestOnly an experienced repairperson should performthis test. Pull the kiln plug¼” from the wall recepta-cle. Start the kiln. Place avoltmeter probe againsteach of the two “hot”blades of the cord plug tomeasure voltage. If voltageis low, try firing the kilnduring periods of low de-mand when voltage ishigher.

Do you see water dripping from the kilnor condensing on the case?Dripping water means theceramic greenware is wet.This slows the kiln to acrawl, because extra en-ergy is needed to evaporatethe water. The greenwareshould be bone dry beforeloading.

Vent the lid and fire no hot-ter than 200°F until mois-ture no longer fogs a mir-ror held near the toppeephole. (Be careful to

6 -

Testing a door switch with an ohmmeter: Thisswitch mounts inside the main switch box.

While the kiln is firing, measure voltage atthe cord plug. Be sure not to touch themetal part of the voltmeter probes.

Testing a door switch with an ohmmeter: Thistype of switch mounts on top of the kiln.

Testing for voltage at the red and blackoutput wires on the back of the Sentry.

With a mirror, you can detect moisture es-caping from the kiln. Keep the lid in thevented position until the mirror no longerfogs.

avoid burns.) The mirror must be at room temperature, nothot, so hold it near the peephole for only several seconds.

Did firing time suddenly, or gradually,become longer? Suddenly:This indicates a drop in voltage during peak demand, a badrelay or a broken element. See page 5 to test elements; page15 to test relays.

Has anyone recently worked on your kiln? Some kilns with se-ries-parallel elements will continue to fire even if they aremis-wired. But they will not fire as hot as they should. If yoususpect this, unplug the kiln, open the kiln’s switch box, andvisually inspect the wiring. Compare it to the wiring diagramfor your kiln.

Gradually:This is usually caused by worn elements. Keep a record of fir-ing times. When elements begin to wear, firing time willgradually increase.

Does your kiln have infinite controlswitches?If so, turn the switches to a higher setting.

Does firing time vary depending on timeof day or season?This indicates low voltage during peak demand.

Is the kiln on its own circuit, or does itshare the circuit with other appliances?The kiln should be on its own circuit. Other appliances onthe circuit can slow down the firing.

Is the circuit wire gauge heavy enough forthe kiln’s amperage?See catalog specifications for your kiln, or the instructionmanual. Use copper wire, not aluminum. Consult a qualifiedelectrician.

How far away is the breaker panel fromthe kiln?If it is over 50 feet, the wire gauge should be one gaugeheavier than the catalog recommendation.

Check kiln amperage with an ammeter.Ammeter TestThe ammeter measures the amps that the kiln draws. If an el-ement is burned out or a relay is broken, the kiln will drawless amperage. See the electrical data plate for your kiln’srated amperage. Before checking amps, check voltage underload, page 6. (If voltage is low, amperage will be low too.)

Only a qualified repair person or electrician should performthis test.

Shut off circuit breaker for the kiln’s wall receptacle.

Open thekiln’s switchbox. Placethe ammeteraround ei-ther of thetwo hotwires com-ing into theswitch boxfrom thecord set.

Leave the switch box open, but be careful not to touch theelectrical components during step 4. Electrical parts in-side the switch box carry live voltage when the power isturned on.

Turn on the breaker. Start the kiln. Use the Element Testoption. (It appears as in the display. See “Options”in the Sentry operator’s manual.) The ammeter will showthe total amperage that the kiln is drawing.

Kilns with more than one relay: By checking the amperageof each individual relay, you can find burned out elementsor a bad relay. Clamp the ammeter around one wire thatgoes from the relay to the element(s).

Result: Amperage is a little below normal.Consider replacing elements. The voltage could also be low.

Result: Amperage is way below normal.The problem is most likely a broken element or relay, or ele-ments of the wrong resistance. See next section, “Some ele-ments do not fire.”

PROBLEM Some elements donot fire.What is the kiln model? Which elementis not firing?See your wiring diagram. Perform either the Element GlowTest or the Scorched Paper Test:

Element Glow TestThe kiln should be empty. Close the lid or door.

In Ramp-Hold, fire at a rate of 9999 to 500°F/260°C. Whilethe kiln is firing, study your kiln’s wiring diagram. It willshow which elements are wired to each relay.

At around 400°F/204°C, carefully lift the lid or open thedoor slightly until you can see the glowing elements.

Use a protective glove. Keep your face well away from the fir-ing chamber. Do not reach inside the chamber. DO NOTTOUCH THE ELEMENTS WITH ANYTHING. Lift thelid for only a moment, then close.

The center elements in most 7, 8, 10 and 12 sided kilns willnot glow brightly, but there should be a faint redness. It iseasier to see the elements with room lights turned off. Somekilns take 40 minutes before the elements glow red.

- 7

The ammeter attaches to only one cord set hot wire. Besure breaker is shut off before you remove the kiln’s switchbox. DO NOT TOUCH WIRES after you turn the breaker on.

Scorched Paper Element TestCut paper into 1” strips.

Turn the kiln on for a minute or two.

UNPLUG the kiln or disconnect the power.

Open the lid. Place a paper strip on an element for threeto five seconds. If the paper darkens, the element isworking.

Repeat for each element.

(This test is courtesy of Carl E. Bosard, kiln technician.)

Test result: All the elements for one relay remainoff.

If all the elements on the same relay are out, try connectingthat bank of elements to a different relay. If the elements fireon a different relay, unplug kiln and open the switch box.Look for a disconnected wire between controller, relay andelements. If wiring is okay, replace the relay the elementswere originally connected to.

If the bank of elements do not fire after connecting to a differ-ent relay, test elements with an ohmmeter. See page 5.

Test result: Some, but not all, elements for onerelay glow.

If more than one element is wired to the relay, the dark ele-ment is probably burned out. The problem is not the relay.Open the switch box. Look for a disconnected wire betweenthe relay and element. If wiring isokay, test the elements with anohmmeter. (See page 5.)

Have you checked thekiln for looseconnections?UNPLUG kiln/disconnect thepower. Open the kiln’s switchbox. Look for loose, corroded or

discolored element connectorsand wire terminals. They willappear dark, greenish-tur-quoise and sometimes white.Cut off over-heated wire termi-nals and crimp on new termi-nals. Remove the damaged ele-ment connector and inspectthe element end. If the elementis damaged, replace the ele-ment. Otherwise sand the ele-ment end and install a new element connector.

Replace any wire in the switch box that is corroded or hasbrittle insulation.

Does the kilnhave a highamperage fuseblock?Kiln Switch BoxHigh AmperageFuse TestThis fuse box is usedonly on high amperageki lns such as theDragon, Viking-24 andViking-28. The fusebox usually contains sixfuses. If a fuse blows,one set of elements willstop working. To testfuses, disconnect thepower. Place the leadsof an ohmeter on eachend of a fuse. (It is okayto leave the fuse you aretesting in the fuseholder.) An OPENreading on a digital me-ter , or no-nee-dle-movement of ananalog meter, indicatesa blown fuse. If fusesare inserted up-side-down, they will beloose, which will re-duce amperage avail-able to the kiln. Thiscould also cause thefuse to blow.

Does the kiln have an infinite controlswitch wired to the elements that do notfire?If the relay and elements have tested okay, replace the switch.

8 -

The fuse must be aligned as shown above. If it isinserted upside-down, it will not make goodconnection. If the prongs on the fuse holder areloose, squeeze with pliers to tighten.

Tighten loose push-on connectorsby squeezing gently with pliers.

The indent on the crimping tool goeson the side opposite the seam of theconnector. Test the crimp by pullingon the wire firmly.

High amperage fuses are located inside a junc-tion box on some models.

Test a high amperage fuse with an ohmmeter.You can test the fuse without removing it fromthe fuse holder.

Elements wired in series to the same relay: If one element is burned out, none of theelements will fire. See the light bulbs above.

Elements wired in parallel to the same relay: If one element is burned out, the otherelements will still fire. See the light bulbs above.

PROBLEM Kiln heats unevenly.How uneven is the temperature in thefiring chamber? If only slightly uneven:Load more ware in the hot section and less ware in the coolsection. This balances the load.

If very uneven:Check for burned out elements and bad relays. See “Some el-ements do not fire,” page 7.

PROBLEM Circuit breaker tripsor circuit fuse blows.Does the circuit breaker shut offimmediately after the kiln is plugged inor turned on? Breaker trips immediately

after the kiln is plugged in.The kiln plug, wall receptacle, orany connection between the powercord and relay(s) has a short-cir-cuit. Check the plug for discolor-ation and heat damage. Replace thecord and wall receptacle when theplug shows heat damage.

Breaker trips immediatelyafter the kiln is programmedand the firing starts.

The kiln has a short-circuit somewhere between the relaysand elements. Unplug the kiln/disconnect the power, removethe kiln’s switch box, and check for disconnected or damagedwires. Check for mis-wired elements. Keep the kiln un-plugged until you have found the problem.

Does the circuit breaker/fuse shut offonly after the kiln has fired for awhile? Is the breaker and circuit wiring the recommended

size for the kiln’s amperage?Check the electrical requirements for your kiln in the catalogspecifications page. If the kiln is direct-wired, make sure thewire between the kiln and wall is heavy enough.

Have you had hotter elements than the standardelements installed in your kiln?

This could increase the kiln’s amperage, causing the breakerto shut off.

Is the kiln too close to the circuit breaker or fusepanel?

Heat from the kiln may shut off the circuit breaker or blow afuse.

Check electrical connections for tightness.Loose connections over-heat, build resistance, and trip thebreaker/blow the fuse. Does the circuit breaker panel or walloutlet feel hot? If so, have repaired by an electrician.

Unplug kiln/disconnect the power. Open the kiln’s switchbox and check for loose wires. Loose or corroded elementconnectors and wire terminals will appear black or green-ish-turquoise. See “Have you checked the kiln for loose con-nections?” page 8.

If the above checks out okay, replace the breaker.As circuit breakers age, they sometimes weaken and trip tooeasily. Even a new circuit breaker can be defective. (A circuitbreaker should be replaced only by a licensed electrician.)

PROBLEM Kiln switch box highamperage fuse blows.

The high amperage fuses are on kilns rated higher than 50amps, such as the Paragon Dragon and Vikings.

The high amperage fuse block usually contains six fuses. If afuse blows, one set of elements will stop firing. (See page 8.)

Does the fuse blow immediately after thekiln is turned on?The kiln has a short-circuit. Disconnect the power, removethe switch box and check for disconnected wires ormis-wired elements. Keep the kiln disconnected until youhave found the problem.

Does the fuse blow after the kiln hasfired for awhile?Disconnect the power. Open the kiln’s switch box and checkfor loose wires. Make sure the fuses in the fuse holder aretight and aligned properly. (Upside-down fuses can be loose,over-heat, and blow. See photo, page 8.)

PROBLEM Kiln switch box ½amp fuses keep blowing.What size fuse are you using?Correct fuse: AGC ½ A 250V AC.

Test the ½ ampfuse.Kiln Switch Box½ Amp FusePower Test

UNPLUG thekiln/disconnect thepower. Remove the 4screws holding thecontroller board face-plate to the switchbox. Lift faceplate outof box and let theboard hang on the out-side of the box withthe back of the boardfacing you. Discon-nect the bottom plug

- 9

The kiln switch box fuse holder.

The power input plug has been removed fromthe bottom of the board.

from the back of the board. (That is the power inputplug with the orange, white, blue, and green wires.) Ap-ply power to kiln. If the ½ amp fuse blows, replace thetransformer. (If the fuse does not blow, the problem isa board or relay. Go to step 2.)

Disconnect the power. Connect the bottom plug to theback of the board. Dis-connect the top plug(the one with theblack, brown, red,purple, and yellowpower output wires).Apply power to thekiln again. Programthe controller to fire to1000°F at 9999° rate inRamp-Hold mode.Press . If thefuse blows, replace orservice the board. (If the fuse does not blow, the prob-lem is caused by a short in the coil of a relay. Go to step3, below.)

UNPLUG kiln/disconnect power. Reconnect thebottom plug to the back of the board. Reinstall theboard in the switch box. Open switch box. If your kilnhas one relay connected to the controller, replace therelay. Kilns with more than one relay: Perform the nexttest:

Relay Coil TestDisconnect the twocontroller-to-relay leadwires from the first re-lay. Touch ohmmeterprobes to the same twoterminals on the relay.A good relay readsabout 80 ohms. A relaywith a short in its elec-tromagnet will read 0 -2 ohms, which will blowthe kiln’s switch box fuse. Test each relay.

Check the fuse holder connections.UNPLUG the kiln or disconnect the power. Open the switchbox. Find the fuseholder. (See page 2.)Check the push-on con-nections for tightness.Loose connections cancause the fuse to blow. Ifthey are loose, tightenwith pliers. (See photo ofpliers, page 8.)

PROBLEM Wall outlet gets hot.Replace the wall outlet.Are the receptacle and cord of the proper size for the kiln? Ifyou smell burning plastic, turn off the breaker immediately.Touch the wall receptacle faceplate. If it feels hot, replace thereceptacle. Replace the kiln cord if it has been damaged byheat from the outlet. DO NOT FIRE THE KILN UNTILTHE RECEPTACLE AND CORD ARE REPAIRED!

Temperature,Display, andKeypad ProblemsPROBLEM Controller readswrong temperature.What happens when you move thethermocouple tip?Reach inside the firing chamber and wiggle the thermocou-ple tip. If the displaymakes a sizable jump intemperature, or thetemperature becomeserratic, replace thethermocouple.

This test does notapply to a thermo-couple inside a pro-tect ive ceramictube.

How close to the thermocouple areobjects inside the firing chamber?Keep shelves, posts, and ware 1 ½” away from the thermo-couple.

Are thermocouple wires tight andconnected to the correct terminals?Inspect the thermocouple connections on the back of theboard. (See page 3 for instructions on removing the board.)Pull the thermocouple wires to be sure they are tight. Some-times the connector buttons can stick in the down position,resulting in a loose connection. But the connection looksokay, because the wires are still inserted all the way.

Does the thermocouple have a ceramic block? (It would belocated on the other side of the wall where the thermocoupletip appears in the firing chamber. Be sure to unplug the kilnbefore removing switch box.) The screws in the ceramicblock must be tight. Make sure the wires coming from thethermocouple and the thermocouple-to-controller wires are

10 -

The 18” thermocouple should protrude into the

firing chamber ½” - 58”. The ¼” thermocouple

should protrude into firing chamber 1”.The ohmmeter probes are placed on the relayterminals that power its 12 volt electromagnetcoil. See the relay diagrams on the cover andpage 2.

The top plug has been disconnected from theboard. These are the wires that send a signal tothe relay(s).

Checking the push-on connectors for tight-ness on the ½ amp fuse holder.

connected with proper color po-larity at the ceramic block and theback of board.

If the wires are reversed, the tem-perature will appear to cool ratherthan to heat. You will also get a

(Thermocouple Reversed)message. See page 16.

Is the thermocouple ora bare thermocouple wire touching themetal case of kiln?That can cause erratic temperature readings. Remove switchbox to inspect. Also make sure the thermocouple wire insula-tion is in good condition. A bare spot touching the kiln casecan throw the temperature readings off.

Are you using the correct thermocouplewire?If you are using the wrong wires to connect the thermocoupleto the controller, the temperature will be inaccurate.

Type-K Thermocouple WireYellow wire (+ terminal)Red wire (- terminal)Brown or yellow outer wire insulation

Type-S & Type-R Thermocouple WireBlack wire (+ terminal)Red wire (- terminal)Green outer wire insulation

Thermocouple Sheath TypesType-K: Black or silver metal sheathType-S: White ceramic ¼” wide protection tube

Is the correct thermocouple type selectedin Options?The Sentry can be used with Type-K, -S or -Rthermocouples. Use the option, accessed through theOptions key, to select the thermocouple type for your kiln.When the temperature reading is inaccurate, check that thecorrect thermocouple type has been selected.

If Type-S or -R has been selected, but your kiln is wired witha Type-K, your kiln will underfire. If you select Type-K andyour kiln is wired with a Type-S or -R, your kiln willOVERFIRE.

Any time you use the option (Reset), use the Op-tion to select the correct thermocouple. The Reset optionchanges the thermocouple selection to Type-S. See your op-erator’s manual for instructions on setting the options.

Has a thermocouple offset or cone offsetbeen entered that you forgot about?See the option, which is accessed through the Op-tions key, in your operating manual.

How far off is the temperature?Ceramics: Pyrometric shelf cones are the best calibrationstandard for ceramic firings. If all your cones consistently un-der- or over-fire, adjust the controller temperature using themethods below. Use witness cones in every firing. Keep a re-cord of every firing.

Compensating for temperature drift using offsets: Usethe option to adjust the temperature setting of yourcontroller. Ceramic kilns: You could also use the op-tion. See your operator’s manual.Compensating for temperature drift by programming:Simply enter a temperature that will compensate for the ther-mocouple temperature drift. Cone-Fire mode on ceramickilns: Enter a different cone number, or use hold, to compen-sate for temperature drift.

If the temperature is more than 45°F/25°C off, replace thethermocouple. If the temperature is still off after you replacethe thermocouple, return the controller for repair.

PROBLEM The kiln overfires.See also “Controller reads wrong temperature,” page 10.

Were there error messages such asHTdE?If not, the thermocouple gave a faulty reading, so the control-ler did not shut off the kiln.

Has the thermocouple been pushed out ofthe firing chamber?The 1

8” diameter thermocouple should protrude into thechamber at least ½” to 5

8”. The ½” - ¼” diameterthermocouples should protrude 1”. Sometimes a shelfnudged against the thermocouple will push it out of the firingchamber.

If this has happened, remove the thermocouple ceramicblock. (On most kilns, you will need to open the kiln switchbox to gain access to the ceramic block.) Gently pull the ther-mocouple, straightening the wires attached to the ceramicblock. If necessary, reposition the wires under the ceramicblock screws. Reinstall the ceramic block.

Do the elements stay on after you pressSTOP or after HTdE appears?If so, the electrical contacts inside a relay are stuck in theclosed position. This will also cause elements to turn on assoon as you plug in the kiln. Replace relay. See “Relay 12 VoltBattery Test,” page 15.

Is a portable wall-mounted controllerpositioned upright?Portable TnF 2 wall-mounted controllers equipped with amercury relay must be placed in an upright position. If theyare placed flat on a table, the mercury relay will remain on allthe time.

- 11

Tightening screw in the thermo-couple ceramic block.

PROBLEM The controller won’tstay on hold.Faulty relay.When you program a hold, but the temperature dropssteadily, a relay may be worn out. A weak relay will shut off be-cause the electromagnet inside the relay is too weak to turnon the power. Also, a relay with contacts stuck in the “on” po-sition will cause the temperature to rise during hold.

PROBLEM The display showserratic temperature readings.The controller measures firing chamber temperature every10 seconds. The temperature shown in the display is the av-erage of the last three samples. Thus, the displayed tempera-ture is the average temperature for the past 30 seconds.

It is normal for the temperature to jump up or down a few de-grees during firing. As temperature rises, the readout will notshow a steady climb, but rather minor jumps up and down.This section of the troubleshooter is for readouts that are er-ratic by 10 - 15 degrees and more.

Does erratic temperature display start ataround 1600°F?A poor circuit ground can cause high temperature erraticreadings. So can a thermocouple that touches a grounded ob-ject such as the kiln case.

Is temperature erratic only when theelements are on?Power wires (cord-to-relay and relay-to-element wires)placed near the controller and thermocouple wire cause thistype of fluctuation. Fire the kiln to around 600°F. PressSTOP. This will shut off the elements. If the temperaturedisplay is no longer erratic at IdLE, try rearranging the wiresinside the switch box.

Do the relays chatter? Does thetemperature fluctuate in time with theclicking of the relays?A relay with a short in the electromagnet can cause an erraticdisplay. The relay draws too much current, draining voltagefrom the board and interfering with normal display. Anothercause is a bad transformer that produces low voltage. See“Controller Power Input Test,” page 4.

Electrical “noise,” which is random electromagnetic signals,can cause the controller temperature to become erratic.Sources of noise are a chattering relay, defective lid or doorswitch, nearby arc welding machines and heavy electric mo-tors. Placing the controller or thermocouple wires too closeto flourescent lights can also cause noise. See “The relaychatters or buzzes,” page 13.

Is the temperature display erratic atroom temperature?Perform the “Thermocouple Test,” page 14. If the display atroom temperature is still erratic with the paperclip in placeon the back of the board, the thermocouple is not the cause.

Has the thermocouple been installedcorrectly? Is the thermocouple worn out?Make sure the thermocouple remains out of contact with thekiln case or anything metallic. Position thermocouple leadwires away from other wires inside the switch box. Thoughprotected by insulation, the thermocouple wires are sensitiveto electromagnetic waves from other wires. Make sure ther-mocouple wires are attached to the correct terminals on theceramic block (if any) and controller board. Be sure the ther-mocouple wire ends are separated where the insulation hasbeen stripped. A worn thermocouple can cause erratic tem-perature readings. Wiggle the thermocouple tip. If the tem-perature jumps by a wide margin, replace the thermocouple.

What is the condition of the wallreceptacle?A damaged, over-heated wall receptacle can destroy thegrounding connection to the kiln, making the display moreprone to erratic temperatures. Replace a damaged recepta-cle. If the cord shows heat damage, replace it also.

Have you recently changed circuit wiring(new location or new circuit)?If erratic temperatures appear momentarily each time the re-lays click on, have an electrician check the electrical circuitfor a poorly connected grounding wire.

Did you recently change the transformer?A transformer of the wrong voltage can cause an erratic tem-perature display and missing display digits. (See the trans-former diagrams on the cover.)

PROBLEM The display remainsstuck.Stuck key.Return the controller for replacement of key pad.

Electrical noise.Sometimes a chattering relay or other source of electricalnoise freezes the display message. Turn off the power for tenseconds. If that does not correct the problem, return theboard for servicing.

PROBLEM Display digits burnedout (parts of display missing).Has the transformer been replacedrecently?A 120 volt transformer installed on a 240 volt kiln can burn outdisplay digits. (See the transformer diagrams on the cover.)

12 -

Have you checked the transformer?Low voltage from the transformer to the board can prevent afull display. The controller shows all 8s at start up to test thedisplay. If the controller is underpowered, it will not get out ofthat test mode. This results in all 8s in the display, or only acenter period. See “Controller Power Input Test,” page 4.

PROBLEM The “1” and/or the “4”key does not respond.Have you turned on Program Lock?Check the Program Lock (displayed as ) in youroperator’s manual in the “Options” section. It deactivates theprogramming keys so that programs cannot be tamperedwith.

PROBLEM Ramp-Hold targettemperature shown in ProgramReview is lower than thetemperature you entered.What is the maximum temperature ratingof your kiln?The controller is set at the factory to fire no hotter than themaximum temperature of your kiln. If you enter a highertemperature than the maximum, the controller will default tothe kiln’s maximum temperature.

The temperature rating of your kiln is listed on the electricaldata plate on the side of the switch box. You can also checkthe option. (See your operator’s manual under Op-tions.)

NoisesPROBLEM The relay chatters orbuzzes.Has the relay been damaged by heat? Arethe connections tight?To turn on the elements, the Sentry controller sends powerto the relays. Inside each relay, the power from the controllercharges an electromagnet, which closes electrical contactsthat turn on the elements.

During normal operation, a relay makes a clicking noise everytime its electromagnet brings the contacts together. (Mer-cury relays are silent, however, because they don’t use me-chanical contacts.)

Sometimes a relay makes a chattering or buzzing instead of aclicking noise. This is usually because the wires inside theelectromagnet have over-heated, burning the insulation on

the wires and weakening the electromagnet. Since the mag-net is no longer strong enough to pull the contacts tightlytogether, the contacts chatter instead of click.

Before you replace a chattering relay, check the wires con-nected to it. A loose connection can cause even a new relay tochatter.

Are the relays receiving enough voltage?Voltage at the red and black wires on the back of the control-ler should be 12 volts DC when the controller sends power tothe relay(s). Voltage below 9 volts DC may not be enough todrive the relay(s), or may cause a relay to chatter. See “Con-troller Power Output Test,” page 5, and “Controller PowerInput Test,” page 4. If these controller tests check out okay,replace the relay that chatters or buzzes.

PROBLEM The controllerkeeps beeping.Alarm is set to a lower temperature.Turn off the alarm by pressing . Then program thealarm to a different temperature. See the operator’s manual.

Error MessagesSome error messages are accompanied by an alarm. To turnoff the alarm, press .

PROBLEM BAdP / BadProgrammingThis message appears when a program has been enteredwith 0 rate in the first segment.

PROBLEM ETH / ElectronicsToo HotThe circuit board temperature is above 185°F/85°C. A relaywith a short can cause the board to get too hot. Perform the“Relay Coil Test” shown on page 10.

The thermocouple or a bare part of the thermocouple wiretouching a grounded object, such as the kiln case, can causean message.

Is room temperature unusually high?Open windows and use a fan to circulate air in the room be-fore firing the kiln or furnace. If you have more than one kilnin the room, place them farther apart. Never allow the firingroom temperature to exceed 110°F/43°C. (Measure roomtemperature three feet away from the kiln.)

Defective controllerIf appears when the room is not hot, and the relays andthermocouple are okay, return the controller.

- 13

PROBLEM FAIL / ThermocoupleFailureKeep a spare thermocouple on hand. Replace the thermo-couple when you get a message. If the appearsafter you have replaced the thermocouple, try the following:

Are thermocouple wires connected to theboard correctly?

kiln. Remove the 4 screws holding the controllerboard faceplate to the switch box. Lift faceplate out of box.Look at the back of the board. You should see a yellow wireand a red wire connected to the thermocouple connectionblock at the bottom of the back of the board. (See diagram,page 2.) If one of these wires is disconnected or loose, recon-nect or tighten.

It is pos-sible that a wire pushed allthe way into the connectioncan still be loose. This is be-cause a button can stick,leaving the wire loose insidethe connection. Test by pull-ing on each wire.

What is thecondition of thethermocouple lead wires?Check to make sure the insulation is in good condition. If theinsulation rubs off and the bare thermocouple wire touches agrounded object inside the switch box, can appear.Also make sure that the thermocouple is not touching thekiln case.

Test the controller with a short piece ofthin wire.If the wires were attached securely to their connectors, per-form this test:

Thermocouple TestRemove thermocouple wires from their connections.Some Sentry versions have lever connectors; othershave push-button connectors.

Insert a thin piece of wire in thethermocouple connectors.(You could use a piece of ther-mocouple wire or paperclip.)

Place the faceplate onto theswitchbox with a couple ofscrews.

Plug in the kiln/connect thepower. If the board reads roomtemperature, replace the ther-mocouple. If it reads ,replace the board.

If you still get a message after replacing the thermo-couple, watch for an erratic temperature display. The prob-lem may be due to electrical noise. See “The display showserratic temperature readings,” page 12.

Multiple-Zone kilnsIn a multiple-zone kiln, if a thermocouple fails, the firing willcontinue as a single-zone kiln so long as one thermocouplestill operates. will appear, alternating with the thermo-couple that failed (i.e. ).

is connected to the left two thermocouple terminals onthe back of the Sentry board; is connected to the cen-ter two terminals; is connected to the terminals on theright.

PROBLEM FTC / Failed to CoolDuring a cooling-down ramp, the programmed rate is fasterthan the kiln can cool. The temperature is above the deviationsetting. (See Temperature Deviation in the operator’smanual.) Program a slower cooling rate.

PROBLEM FTH / Failed to HeatDuring a heating-up ramp, the programmed rate is fasterthan the kiln can heat. The temperature is below the devia-tion setting. (See Temperature Deviation in the operator’smanual.)

Program a slower rate. Or check for worn or burned out ele-ments, defective relays, low voltage and defective thermocou-ple.

PROBLEM FTL / Firing Too LongThe temperature change is less than 27°F/15°C per hour andthe firing time is four hours longer than the current segmentwas programmed to fire. This message can appear duringheating-up or cooling-down segments.

Was the firing too slow?If appears well below the target temperature during aheating-up segment, such as 1000°F for an 1800°F firing, youprobably have a burned out element or relay. See “Kiln firestoo slowly or will not reach temperature,” page 6.

Check for worn or burned out elements, defective relays, lowvoltage and defective thermocouple.

Did FTL appear during a controlledcooling?If appears during a cooling segment, it is usually be-cause the segment was programmed to cool faster than thekiln’s natural cooling ability. To avoid getting the mes-sage, program a slower cooling rate.

14 -

A thin piece of wire being used totest the thermocouple circuit onthe controller.

PROBLEM HTdE / HighTemperature DeviationDuring a heating-up ramp or a hold, the temperature is abovethe deviation setting. (See the Temperature Deviation optionin the Sentry operator’s manual.) The kiln will shut off whenthe error code appears.

This may be caused by a temperature overshoot. See the op-erator’s manual. Check for a stuck relay.

Check the relay(s).is caused by a stuck relay or defective controller. If the

elements remain on after appears, check the relays asfollows:

Relay 12 Volt Battery TestYou will need an ohmmeter, 12 volt battery and 2 clip wires.

WARNING: You must disconnect the controller-to-relaywires to test the relay(s) with a battery. Leaving the wiresconnected could damage the controller.

kiln/disconnectthe power and removeswitch box. Find the twowires going from the con-troller to the relay you aretesting. Disconnect thesewires from the relay. Thenconnect a 12 volt lanternbattery to the same relayterminals (#5 and #6 onthe diagrams shown on thecover) using clip wires.You should hear a clickwhen you make the connection. If there is no click, the re-lay is probably defective. Make sure your battery is goodbefore assuming the relay is bad.

Touch ohmmeter lead wires to relay terminals marked #1and #2 in the diagrams on the cover. With the battery stillconnected, you should get a continuity reading (0 ohms)on the ohmmeter. (This is the same reading you would getif you touched the ohmmeter leads together.) If you get ano-needle movement when the battery is connected, re-place the relay. Place the ohmmeter wires on relay termi-nals marked 3 and 4 on the diagrams and test the sameway.

If the ohmmeter reading at terminals #1 and #2, and then#3 and #4, is 0 ohms when the battery is removed, the re-lay contacts are stuck. Replace the relay.

If the relays are okay and the elements turn on when you re-connect the controller wires to the relays, return the control-ler for repair.

PROBLEM The “LId” DisplayReasons appears in the display:

1) The kiln is equipped with the optional lid safety switch.(The switch turns off power to the elements when the lid ordoor is open.) appears in the display while the lid isopen during firing.

2) On the back of the Sentry circuit board, at the top rightside, is a small two-pin terminal. If the connector on that ter-minal is missing, will appear in the display during fir-ing. The elements will not turn on. (If the two-pin connectoris missing, you can buy another from a computer supplystore.)

3) The safety lid switch is defective or the safety switch wire isbroken.

PROBLEM LTdE / LowTemperature DeviationDuring a cooling-down ramp or a hold, the temperature isbelow the deviation setting. (See “Temperature Deviation”in the operator’s manual.)

Check for worn or burned out elements, defective relays, lowvoltage and defective thermocouple.

PROBLEM PF, PF 2 or PF 3during firing.

alternating with normal display means the power failedduring firing. After power was restored, the firing resumed.

means the power failed. The kiln temperature was be-low 212°F/100°C when the power came back on. The kiln willnot resume firing.

means the power failed during cone-fire mode. It canalso apply to the final segment of a ramp-hold firing wherethat segment’s rate was 108°F/60°C. The temperaturedropped more than 72°F/40°C while the power was off. Thekiln will not resume firing.

Have you had a power failure? PF, PF 2 or PF 3 message, no power failure.Low voltage can cause the kiln to shut off and display

or a blank display. If this happens and you didnot have a power failure, check the wall receptacle, while thekiln fires, for low voltage. (See “Receptacle Under LoadTest,” page 6.) Sometimes there is just enough voltage toprogram the board. But when the relays turn on, the voltagefrom the transformer drops below the minimum operatinglevel, and the display goes blank.

A corroded kiln cord plug or wall receptacle can cause aor a blank display. Pull the plug from the wall.

Clean the plug prongs with fine emery paper or a pencileraser until the prongs are bright. If the plug or wall recepta-cle is blackened, replace. A loose wall receptacle screw orloose circuit breaker screw can also cause a power failure dis-play.

- 15

Testing a relay with a 12 volt lantern bat-tery.

Check transformer if the wall receptacle voltage is okay. See“Controller Power Input Test,” page 4.

PROBLEM PLOG Error CodesA PLOG error code means that the controller failed a self-di-agnostics test. The controller will not operate while a PLOGmessage appears.

Has your controller been near a source ofelectrical “noise”?Electrical “noise” is electromagnetic interference that canaffect the controller. A possible source of electrical “noise”isa chattering or buzzing relay. Other sources are flourescentlights, large electric motors, and arc welders. Flourescentlights can affect the controller if the thermocouple wire orcontroller is placed right next to a large number of lights.This is rare, though. If a nearby motor or arc welder is caus-ing a PLOG error, move the kiln away from those sources.Does your kiln have mercury relays? If so, verify that MOVs,which reduce electrical “noise,” are installed.

How reliable is your electrical source?Low voltage and power spikes can cause PLOG errors.

Have you changed relays to a different type than the originalinstalled on your kiln? The wrong relay type can cause aPLOG error by pulling too much power from the controller.

A relay with a short can cause a PLOG error. It can drain thepower from the controller. Perform the “Relay Coil Test”shown on page 10.

What is the condition of yourthermocouple?PLOG 11, 12 and 13 indicate that a thermocouple is about tofail or that electrical noise is affecting the thermocouple.

Try moving the thermocouple lead wires away from nearbyelectrical wires and relays.

Make sure the bare lead wires extending from the thermo-couple are not touching the kiln case.

If the insulation anywhere on the thermocouple wires isrubbed off, a bare spot on the wire can touch the kiln case.This can result in a PLOG message. Check the wire for dam-aged insulation.

Check for loose thermocouple wire connections on the backof the controller and at the thermocouple. A PLOG error isoften caused by loose screws on the thermocouple ceramicblock. This is located on the other side of the kiln wall wherethe thermocouple extends into the firing chamber. (Note:Your kiln may not have a ceramic block.) It is also possiblethat the screws are tight but that the thermocouple wire un-der the screw is broken.

Replacing the thermocouple usually clears the PLOG 11, 12or 13 code.

Were the relays chattering or buzzing?Electrical noise from a chattering or buzzing relay can causea PLOG message. See page 13.

Clearing PLOG Error CodesClear the PLOG error code by pressing .

If pressing does not clear a PLOG error, turn offpower to the kiln for 10 seconds.

If the PLOG error code still appears, turn off the power.Hold down the and keys while you turn thepower back on. This resets the controller, so you mayneed to reselect thermocouple type ( option) andtype of temperature display ( option). See “Op-tions” in your operator’s manual.

After a PLOG error clears, it is okay to fire the kiln again withclose supervision.

PROBLEM TCdE / UnevenMultiple Zone TemperaturesOn a multiple zone kiln, usually means thethermocouples and elements are improperly wired. A ther-mocouple is turning on the elements to the wrong zone. Forinstance, if the top thermocouple turns on the bottom ele-ments, the kiln will fire out of balance. When zones are out ofbalance by 140°F/60°C, will appear in the display.

Visually compare the wiring of the thermocouples, relays andelements of your kiln to the kiln’s wiring diagram. Also, usethe Element Test option. See “Options” in your operator’smanual.

TCR / Thermocouple LeadsReversedCheck that the thermocouple lead wires are connected to thecorrect terminals. Observe correct color polarity. See yourwiring diagram.

If the insulation on the thermocouple wires is rubbed off, abare spot on the wire touching the kiln case can cause amessage. Check the wire for damaged insulation.

The thermocouple wires must be connected with correctcolor polarity at both the thermocouple ceramic block andthe back of the controller. If you get a message becausethe wires are reversed on the thermocouple block, do not cor-rect the problem by reversing the wires on the back of thecontroller. If you do so, the message will disappear, butthe temperaturewil l be lessaccurate.

16 -

2011 South Town East Blvd.Mesquite, Texas 75149-1122800-876-4328 / 972-288-7557Toll Free Fax: 888-222-6450Paragonind@att.netwww.paragonweb.com