Magnetel ™

Liquid-Level GaugeInstallation Guide

The Measure of Excellence

(972) 241-2161 • FAX (972) 620-140311616 Harry Hines Blvd. • P.O. Box 29242 • Dallas, TX 75229

Website http://www.rochestergauges.com • E-mail info@rochestergauges.com

Magnetel ™

Liquid-Level GaugeInstallation Guide

Form #115-820rev. 09.25.03

ISO 9001 AND QS-9000 REGISTERED

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Construction & OperationMagnetel™ liquid level gauges are designed for centerline mounting or topmounting on bulk-storage tanks, centerline mounting on bobtails or transports.Angle mounting is optional at extra cost.

The materials used in construction are carefully selected for compatibility withthe liquid to be gauged, so, you can expect the unit to provide many years oftrouble-free service.

Magnetel™ gauges are operated by liquid displacement of a float bulb attachedto a counter-balanced float arm. The counterbalance has been adjusted so thefloat will be half-submerged in tank’s liquid.

The main gear at the pivot point drives a pinion gear attached to a center shaft.The 2.2:1 gear ratio converts the 140° float arc to 308° of center shaft rotation.A drive magnet, attached to the end of the center shaft under the gauge head,couples with a dial pointer magnet through the solid, non-magnetic head tomove a pointer around a dial, usually graduated in percent of tank volume. Thelimits of measurement are 5% to 95% or 3% to 97% of tank volume.

Attachment To TankDifferent adapters can be welded or screwed into tanks to attach the gauge.Any used must conform to Rochester Machining Standard MS 508. For stan-dard Magnetel™ gauges the mounting bolt holes are on the vertical centerline.Straddle mounted gauges for mounting bolt holes spanning vertical centerlineare available on special order.

Centerline Mount Straddle Mount

Trouble ShootingLOOK FOR:SYMPTOM

Gauge face notstraight on tank.

Gauge indicatingliquid level inaccu-rately.

Gauge indicatorstaying at somemidpoint regard-less of liquid level.

Gauge continuesreading at low ex-treme when tank isfull.

Gauge not readingat low extremewhen installed inempty tank.

• Mounting adapter lined up improperly.• Centerline gauge used on straddle

mount adapter.• Straddle mount gauge used on

centerline adapter.

• Gauge not fitting tank. Order right gauge.• Gauge mounting adapter not aligned

with tank axis.• Tank is not level.• Liquid-temperature volume changes not

accounted for.

• Float hung not allowing float to follow liquid level — defective gauge.

• Float partially sunk due to leakage or improper counterbalancing.— Replace float or gauge.

• Dial pointer is stuck due to damage orcorrosion. — Replace dial.

• Incorrect or modified float arm installedon gauge. — Replace float arm or gauge.

• Obstruction on tank bottom.• Float improperly counterbalanced for

liquid being gauged. Order correct gauge.

• Float leaks and is filled with liquid.— Replace float.

• Float striking obstructions such as dip pipes or baffles.

• Float or counterbalance striking tank wall. — Incorrect gauge.

• Float not dropping under its own weight.— Defective gauge.

• Float arm too short for counterbalance.

CAUTIONRead completely before attempting installation. These instructions areprepared to assist tradesmen and others generally familiar with liquidstorage tank equipment. Most consumers are not qualified to performthe installation described. If you have any questions about installationor operation of Magnetel™ gauges, contact Rochester Gauges or anauthorized distributor for assistance.

* Specifications are subject to change without notice. Pressure ratings subject tochange due to temperature and other environmental considerations.

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*Use with aluminum flange only.**Use with stainless steel flange only.

The most popular Rochester adapter, 0022-00029, has a 2.5" Male NPT threadwhich screws into a 2.5" Female NPT coupling welded into the tank. The seal-ing gasket and eight mounting studs and nuts are included with the Magnetel™

gauge. Other adapters are the Rochester 0022-00030 which facilitates close orrecessed coupling to the tank head, or the 0022-00500 weld-neck flangewhich extends a short distance from the tank shell. For full details, ask for the22 Series Technical data sheet.

The minimum adapter opening diameter the float and counterbalance mustpass through is 2.25"; the optional “Y” style gauge goes through a 2" NPT cou-pling or a 2” schedule 40 nipple. A 2” NPT threaded adapter is furnished as-sembled onto the gauge. Any adapter used must be installed with its axis trulyaligned with the tank axis. This enables the installed gauge to be exactly hori-zontal and provide accurate gauge readings.

Inspection & Assembly Of GaugeWhen the Magnetel™ gauge is received, remove and inspect it to make sure itis in operating condition. Use the screw and nut or cotter pin provided to installthe float arm and dial (per figure 7, step 8) on the gauge. Make sure the floatwill fall under its own weight by moving the float arm slowly through its rangeto detect any binding or restriction. The dial pointer should move slightly pastthe extreme ends of the dial scale when the float arm reaches the limits of itstravel.

Make sure it is calibrated properly by aligning the float arm with the supportarm. The side or end mounting gauges should then read 50% and top mount-ing gauges should read below empty. The 50% graduation on the dial shouldbe at the 12 o‘clock position after the gauge is installed in the adapter. If youfind any problems call Rochester.

Accuracy PrecautionBefore installing your Magnetel™ gauge, be sure it fits your tank properly. Checkthe length of the float arm, measuring from the pivot point to the center of thefloat bulb. This dimension should be .465 times the inside diameter of any hor-izontal cylindrical tank, and .428 times the inside diameter for mobile tanks withRough-Rider™ gauges.

Before filling the tank, be sure the gauge moves freely inside. Many storagetanks contain dip pipes, baffles, or other obstructions which may interfere withfree movement of the gauge float arm, preventing proper performance.

Accurate measurement of Liquefied-Petroleum Gas, LP Gas, or anhydrous am-monia, NH3, requires converting a volume measured at an observed tempera-ture to the volume at a standard base temperature of 60°F. LP Gas is usually amixture of propane, butane and possibly other gases, so the conversion factoris usually determined from a chart when the specific gravity of the LP Gas is at60°F is known.

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CAUTIONNEVER EXCEED THE MAXIMUM SAFE FILLING LEVEL.The temperature chart for various specific gravities (mixtures) of LP Gas isbased on the permitted filling densities as given in NFPA Pamphlet 58, Stan-dard for the Storage and Handling of Liquefied Petroleum Gases. This chartis required for an LP Gas liquid-level gauge to be listed under the re-examina-tion service by Underwriters Laboratories, Inc. The chart indicates the maxi-mum safe level for LP Gas when the specific gravity and liquid temperatureare known. This safe level allows space in the tank for liquid expansion if theliquid temperature rises.

WARNINGThe gauge is not a substitute for a fixed or adjustable liquid level gauge whichmay be required for filling. Do not use gauge for filling.

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2. Place spiral-wound gasket over hole and under centralizers’ lips. Never re-use a gasket.

Precautions Regarding Removal Of GaugeIf gauge removal appears necessary, only do so under competent supervision.Make sure pressure is entirely down and wind cannot carry fumes near openflames.

Fire Hazard WarningA hazard of fire or explosion may exist if proper methods are not used when in-stalling or removing Magnetel™ from vessels containing pressurized liquid orgas, flammable liquids, oxidizers, NH3 or LP Gas.

Removing The GaugeWhen removing centerline-mount gauges, do not strain or force the parts, es-pecially in lining up the counterbalance. After mounting stud nuts have been re-moved, replace the dial chamber and slowly rotate the gauge left or right untilthe pointer is at the 50% level. In this position, the counterbalance will be par-allel to the support arm and can be easily withdrawn through the opening.

With the same careful manipulation, top-mount gauges may be easily removedalso. Tip the gauge slightly so the pointer rests at its lowest possible position,slowly withdrawing the gauge from the tank.

Installing The GaugeIf the gauge has not been assembled, read the section oninspecting and assembling the gauge.

1. Place the red plastic centralizers on the short end of the studs for the 4 and 7 o‘clock positions with the lips outward and install these studs in the gauge adapter.

Placement Of 4 & 7 O’Clock Centralizers

Placement Of Spiral-Wound Gasket

WARNINGDO NOT TEST THE FLOAT FOR LEAKAGE BY ANY MEANS.If the dial indicates a lower liquid level than what is known, then the gaugefloat may be leaking and may be filled with liquid. Place the removed float ina safe, isolated and well-ventilated area to give the LP Gas or NH3 a chanceto diffuse. With these liquefied gases and other similar products, a danger offloat explosion exists due to liquid or gas expansion resulting from warminga float from any source.

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3. Place two more centralizers over studs in the 10 and 2 o’clock positions.Install these and the remaining studs. The gasket is now centered andretained.

4. Align the float arm with the support and counterbalance mechanism throughthe adapter into the tank. On side or end mounting gauges, rotate 50% ondial to the 9 o’clock position and insert the gauge float. Slowly rotate thegauge until the 50% graduation on the dial is at the 12 o‘clock position(11 o‘clock for straddle mount gauges).

8. After inserting the float and counterbalance into the tank, press the central-izer about halfway into the mounting adapter to center gasket on adapter.

Gas Pressure WarningIn certain isolated cases and with very low temperature, it may be possible toopen a tank with slight loss of gas. A 300 lb. pressure gauge may show a zeroreading and still have up to four or five pounds pressure in the tank. However,pressure is probably being generated all the time and a sudden pressure reduc-tion will substantially increase the rate of vaporization.

NoteMagnetel™ models 6336-8, 6339-8, 6342-8, 6342-8, and 6360-8 (with alumi-num heads) use rubber gaskets. Magnetel™ models 6336-16, 6339-16, 6342-16, and 6360-16 use a Teflon gasket. Magnetel™ models 6339-8, 6342-8,6339-16 and 6342-16 are supplied with a sheet metal stainless steel central-izer. Be sure the gasket or gasket and centralizer have been slipped onto thegauge support before doing step 4. Install the short end of the studs in thegauge adapter (see step 8).

Placement Of Rubber Or Teflon Gasket

Placement Of 10 & 2 O’Clock Centralizers

Inserting The Gauge In The Tank

NoteMagnetel™ models 6336-8, 6339-8, 6342-8 and 6360-8 (with aluminumheads) use rubber gaskets. Magnetel™ models 6336-16, 6339-16, 6342-16,and 6360-16 use a Teflon gasket. Magnetel™ models 6339-8, 6342-8, 6339-16 and 6342-16 are supplied with a sheet metal stainless steel centralizer. Besure the gasket or gasket and centralizer have been slipped onto the gaugesupport. Install the short end of the studs in the gauge adapter (see step 8).This style centralizer cannot be used on top mounting gauges.

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5. Slip the gauge head onto studs and start the mounting stud nut at the 6o‘clock position. Remove the dial and install remaining nuts finger-tight.Tighten nuts near the bottom of head just enough to make the head paral-lel to the adapter face. Tighten in sequence while increasing torque gradu-ally. Make sure the gap between the head and adapter remains the same allthe way around. If it is not, loosen nuts near the narrow gap slightly andtighten nuts near the wide gap. After the nuts have been partially tightenedand head is parallel with flange, apply about 10 ft./lbs. torque using nuttightening sequence. Now, apply about 20 ft./lbs. using nut tighteningsequence. Then apply a final torque of 25 to 35 ft./lbs. to each nut severalmore times in sequence.

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6. Installation InspectionPurge the vessel if necessary. Pressurize it to at least one-third the rated tankpressure if it is a pressure vessel. Check for leakage all around, betweenhead and adapter and around each mounting bolt head. Over-tightening ofmounting bolts may cause cracks or warp the head. If no leaks or other de-fects are detected, fill the vessel. Check for pointer movement after 5% full,prior to filling to the desired level.

7. Re-install the 8" dial chamber using three screws that extend through thebezel into the brackets at the 9, 12 and 3 o‘clock positions.

WARNINGUneven or excessive nut torque can damage gasket and/or gauge head.

Nut Tightening Sequence Installing The Dial Chamber

CAUTIONThe back of the dial chamber must be seated in the gauge head and all threebrackets touching the dial chamber without rocking. If they do not, carefullybend the bracket arms forward until even. Re-install 4" dial using the twoscrews extending through the bezel into the brackets at the 9 and 3 o‘clockpositions.