GGHN Installation and Maintenance Manual

7/31/2019 GGHN Installation and Maintenance Manual

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Gntner de Mexico SA de CV www.guentner.com.mx

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INSTALLATION, OPERATION & MAINTENANCEMANUAL

Water Defrost

GHN.2Freon applications

AGHN.2Ammonia applications

GGHN.2Glycol applications

Index

1. Warranty statement 2

2. General Information 3

3. Functional description 3

4. Description of components 4

5. Set-up and installation 5

6. Information for operation 9

7. Maintenance and cleaning 10

8. Defrost 12


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Warranty Statement

The supplier warrants against defects in workmanship and materials of the product supplied

for a period of 24 months from the time of transfer, provided that they are correctly installedand operated within the recommended limits of the manufacturers technical documentation.

The supplier at its option shall repair, or replace, free of charge to the purchaser all goodswhich become defective during the warranty period as a result of defects in design,workmanship or materials, fair wear and tear excluded, providing that;

- the application is correct- operating and installation instructions are complied with- system component and piping design is in accordance with good refrigeration

practice-

Nitrogen or an inert gas must be introduced into the piping during the brazing of thepiping installation

In order to execute the corrective work or replacement supply that appears necessary, withinthe suppliers reasonable discretion, the purchaser must, following communication with thesupplier, provide the necessary time and opportunity, or the supplier will be freed from theliability of the defect.

The costs arising directly from the corrective work or replacement supply, transport andexchange costs in particular, shall be borne by the purchaser himself. The supplier shall notbe liable for costs incurred in dismantling or fitting replacement parts or for any independent

inspection undertaken by the purchaser. The purchaser shall return any allegedly defectivegoods, carriage paid, to the suppliers works. Upon receipt of the goods and inspectionthereof the supplier shall repair or replace, at the suppliers discretion, the defective goodsand return freight, carriage paid, and without any further expenses. This shall constitute fullcompliance of the suppliers obligations.

No liability is accepted for the consequences of incorrect modifications or repair work beingcarried out by the purchaser or a third party or without the prior permission of the supplier.

It is clearly understood and agreed that any further claims, in particular claims forcompensation for damage and consequential damages not occurring on the supplied item

itself, are excluded.

Furthermore the supplier shall not be liable to the purchaser, or client of the purchaser, forany direct or indirect damages, injury to persons or property or any consequential loss or lossof profits arising from defective goods or workmanship or from any other cause whatsoever.

To obtain warranty service, please contact: [email protected]


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2 General informationThese operating instructions are valid for the following Gntner series; GHN.2, AGHN.2,GGHN.2 with the option "water defrost". This manual is intended as additional informationto the existing general operating instructions of the respective unit series.The option "water defrost" is restricted to the use in normal cooling applications with roomtemperatures (RT) > 23 F.

Units with water defrost differ from units with or without other defrost modes (e.g. electricdefrost, hot gas defrost) in the following important points:

- the unit is higher- the unit is deeper- higher empty and operating weight

Additional elements:- drains- distribution tray- suspension to ceiling (increased load on brackets; spacer sleeve

system)Water defrost operating instructions are such as water quality, temperature and flow rate arespecified on the following sections.

3 Functional description of water defrostFor this option, the cold component parts such as heat exchanger coil, the connection systemand heat exchanger piping of the evaporator or air cooler are defrosted with water.The defrost system is not suited for cleaning the unit. The defrosting procedure has a certaincleaning effect on the surfaces that get into direct contact with the water, but this cannotreplace a thorough manual cleaning of the entire unit.

Description of functions:

During the defrost cycle, the defrost water is evenly distributed over the heat exchanger coil,the connection systems and the heat exchanger piping.As the water trickles through the heat exchanger coil, the frost and ice is defrosted by thedirect contact with the defrost water and also by the heat from the heat exchanger coil.The water is collected below the heat exchanger coil, connection system and the piping in adrip tray. The accumulation of water also improves defrost efficiency because the residualheat from the accumulated water is used. In addition, all of the ice in the defrost water ismelted.


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4 Description of the water defrost component parts

Figure A: Side view Figure B: Detail A

Figure C: Top view of side cover Figure D: Expanded view of the top tray

Drain tray Figure A10 Drain tray11 Support for drain tray12 Drip collection tray in drain tray13 Drip tray drain R 3 (AC: BGAB300)14 Drain heater, mounted by customer

Other parts Figure A15 Mounting brackets16 Spacer sleeve for suspension to ceiling17 Electric heater fan

Gasket Figure B

6 Silicone gasket between tray and casing7 Angle for drip tray rail and mounting of silicone gasket (6)8 Heat exchanger coil9 Casings metal sheet (top)

Chamber Figure C18 Separation sheet for chamber division into wet and dry sections19 Insulation door20 Insulation of chamber casing21 Refrigerant distributor (only for evaporators)

Defrost water distribution system Figure D1 Pipe connection for defrost water supply line 1 (AC: 239)

2 Distribution tube (pressure distribution over width of coil)3 Intermediate distribution sheet (slots parallel to coil depth)4 Distribution tray (slots parallel to coil depth)5 Drip tray cover


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5 Set-up and installation

5.1 Unloading and UnpackingFor information on unloading and unpacking, please refer to the main operating instructions.

5.2 InstallationFor units with water defrost it is especially important to pay attention to a correct horizontalpositioning of the distributor tray in width and in depth of air direction.

(16)

For units that are suspended, (e.g. hung from the ceiling) it is very important to observe thefollowing:

The general operating and maintenance instructions have to be observed. For the waterdefrost option, one spacer sleeve (16) has to be mounted per connection between themounting bracket of the unit and the suspension point at the building structure (e.g. ceiling orbracket).There should be enough free space above the distribution tray(s), so that the tray can be liftedout of the guide rail for cleaning and maintenance. The space has to be at least 13/16 in.


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After the installation, all legs for transportation have to be removed, and at the air inlet side,the spacers for the legs have to be removed. The transportation legs and the correspondingparts have to be removed, because they are not considered for the static unit load in itsoperating state. They also have to be removed from the unit for the following reasons: frostformation, corrosion, cleanliness and visual appearance.


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5.3 Feed line for defrost water

I Mechanical diagram with one-piece distribution trayII Mechanical diagram with two-piece distribution tray

III Mechanical diagram with three-piece distribution trayIV Mechanical diagram with four-piece distribution tray

L1 Length of distribution tray (total length of all trays)L2 Finned length (length of heat exchanger coil)L3 Length of distribution tray above connection chamber (connection side (ANS) in air direction (LR) right)L4 Length of distribution tray above tube bend chamber (connection side (ANS) in air direction (LR) right)

1 Cold room2 Wall or insulation3 Warm room RT>32 F4 Connecting tube and if applicable branch regulation valves and stop valves (mounted on site)5 Feed line always in middle6 Throttle valve mounted on site, no ball valve7 Soil filter

If the unit is operated at room temperatures < 32 F, one of the following measures has to beused to keep the piping of the defrost water feed line free of ice:

The connecting tubes in the cold room (1) have to be sufficiently angled towards thedistribution tray.

The connecting tubes in the cold room (1) have to be sufficiently angled towards thewarm room (3), and have to be equipped with an automatic drain of the tubes aftereach defrost cycle.

Equip piping with permanent trace heating and insulation.

The water defrost should be operated simultaneously with another type of defrost suchas hot gas or glycol defrost.


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For wide units with several fans, the tray is assembled with several parts and consists of 1 - 4individual segments. The precise amount of distribution trays is indicated in the drawings onpage 6, in chapter 4.3. Each distribution tray has to be connected on site according to thedrawings. The connecting piece for the defrost water feed line is consistently designed as a 1 copper thread connection (the stainless steel design can differ). It should be possible to

undo the connection for cleaning and maintenance purposes.The pre-distribution provided on site to the individual trays has to be provided in such a waythat an even distribution of the water volume flow is possible. If necessary, throttle valveshave to be integrated in each branch.For recommendations concerning the water volume flow, see chapter 5.2.No soil particles may enter the distribution tray system.Appropriate soil filters have to be implemented in the feed line on site by the customer.

5.4 Defrost Water DrainThe precise number of drip tray drains is specified in the drawing of the unit.Each drip tray drain is equipped with R 3" plastic screw threads that can be connected to the

drain pipe. The incline and the tube cross section have to be designed in such a way that thecross sections of the tube system is large enough for the volume flow of the defrost water andthe ice water. At RT < 32 F, heating has to be installed for the drain pipes and the piping hasto be insulated.

The drain pipes are designed for the maximum water flow rates. For the recommendeddefrost water volume, please refer to chapter 5.2.

Drip Tray Drain[pieces] x [size]

Inside Diameter[pieces] x [size]

Max. water flow rate[gpm]

1 x 3 1 x 3 3/16 in diameter 48.432 x 3 2 x 3 3/16 in diameter 96.863 x 3 3 x 3 3/16 in diameter 145.34 x 3 4 x 3 3/16 in diameter 193.73Note: The water flow rates are calculated for non-pressurized drains (w = 0.6 m/s).

5.5 Position the refrigerant distributor(s)This paragraph only concerns evaporators with refrigerant distributor(s).The refrigerant distributor(s) for evaporators have to be positioned in the connection chamberwhere the water defrost is effective. This means the distributor must be in direct contact with asufficient amount of defrost water. The ice that is formed during refrigeration has to becompletely defrosted during the defrost phase.


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6. Information for operation

6.1 Defrost Water QualityThe water that is used for the water defrost has to possess the following properties:

Property Desired QualityAppearanceColorOdorMicrobiological purity

clear, without sediments, free of suspended solids and particlescolorlessodorlessdrinking water quality

Temperature 50F - 86FpH value at 68F 6.5 - 8.3El. conductivity (77 F) mS/mEl. conductivity (77 F) mS/m

< 10 (Is this correct?)< 100 (Is this correct?)

Alkaline earths (Ca2+, Mg2+)

mol/mTotal hardness dGH

< 0.05

< 0.25Chloride (Cl- ) g/mSulfate (SO4

2-)g/m< 10< 15

6.2 Defrost water volume flowWater flow rate (defined value) per m coil and chamber surface:

5.6 [m/(hxm)]

Example:L finned = finned length = 1600 mm = 1.6 mT finned = finned width = 400 mm = 0.4 mL connection chamber (L3) = 200 mm = 0.2 mL tube bend chamber (L4) = 100 mm = 0.1 m

Note:For this calculation, only the area of L connection chamber (L3) and L tube bend chamber(L4) above the bare coil is considered. The defrost water is distributed in this area. Seedrawing on page 6, chapter 4.3

Area connection chamber + Area bare coil + Area tube bend chamber = Total covering area(0.2 m x 0.4 m) + (1.6 m x 0.4 m)+ (0.1 m x 0.4 m)= (0.2 m + 1.6 m + 0.1 m) x 0.4 m = 0.94 m

Total volume flow = 5.6 m/(hxm) x 0.94 m = 5.26 m/h1 m/h = 4.4 gpm

If a volume flow meter or volume sensor is installed in the feed line for the defrost water, thismeter should be used to adjust the design value. When using a volume sensor, e.g. a watermeter, it is additionally necessary to measure the time with a stop watch.

If there is no possibility to measure the volume flow, the openings of the connection side andthe tube bend side have to be opened and the water amount has to be adjusted in such a waythat it is evenly distributed across the depth of the coil in air direction. If the set water amount


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is too low, the center of gravity at the outlet is in the middle and the danger of insufficientdefrost exists especially in the air inlet area. If the water amount is too high, this leads todisproportionate water distribution at the edges which results in water leaking into the unitfrom the heat exchanger coil. Another result is that the ice in the middle of the coil defrostsslower than the edges.Additionally, the water amount must be enough so that the defrost water, that gathers in the

bottom drain tray, reaches the level of the baffle plates. This means that some of the waterdrains off via the baffle plates.

7. Maintenance and cleaningFor general maintenance and cleaning of the unit, please observe Chapter 7 of the mainoperating instructions of the unit.

For maintenance or cleaning of the defrost water distribution system, the system can bedisassembled from the main unit. At first the feed lines have to be disconnected. Then the twoscrew connections of the angle brackets at the side of the drip tray cover have to beunscrewed. For unscrewing the screw connections, the doors of the connection and tube

bend side chambers have to be opened. If the tray consists of several parts, the screwconnections of the center bracket(s) also have to be unscrewed. Now the tray can be liftedfrom the front and the back guide rails and then be turned and removed.


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Defrost water distribution system1 Connecting pipe for defrost water supply line 1 (AC: 239)2 Distribution tube (pressure distribution over width of coil)3 Intermediate distribution sheet (slots parallel to coil depth)

4 Distribution tray (slots parallel to coil depth)5 Drip tray cover6 Support for distribution tube (2)7 Cladding sheet8 Polyform cushion

The distribution sheet can now be opened. For disassembly, all screw connections of thecover (5) have to be removed. If all single parts, such as the distribution tube (2) need to becleaned then the cladding sheet will need to be removed.Note: The evaporator or air cooler does not function without distributor tray(s)! Without thedistribution trays the unit would draw infiltrated air that does not flow across the heat

exchanger coil as intended.

The parts of the defrost water distribution system can now be cleaned and descaled. Cleanoutlet openings of the distribution tube (2) are import for even water distribution. For materialtolerance, please observe the general unit operating instructions, when selecting and usingdetergents. Only use detergents that are neutral and not corrosive to the materials used!

After the cleaning of the component parts the distribution tray has to be mounted as follows:Place the intermediate distribution sheet (3) into the outer distribution tray. Place thedistribution tube (2) into the supports provided for this purpose (6) and screw the claddingsheet (7) to the distribution tray. Now the polyform cushions (8) have to be inserted and the

drip tray cover (5) has to be screwed in place.When placing the distribution tray on the unit, please observe that it has to be positioned veryprecisely into the designated area.


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Before re-setting to refrigeration mode, no residual water may be left on any inside or outsidesheet metal parts, because otherwise this can lead to the formation of ice particles and canresult in further damage.

8 Defrost process

8.1. Defrost cycle

The operator of the installation has to determine the defrost cycle (intervals for defrost). Forexample; twice a day, or once a day, or every two days, etc.

The defrost cycle is mainly determined by:

Specific Installation Parameters (the larger the difference between air inlet temperatureand evaporating temperature, the shorter the defrost intervals)

Goods to be cooled (packaged or unpackaged)

Intervals of charging and withdrawal (and also the operating time per day or operatingtime on weekends)

The moisture entering the room from the products to be cooled and through theopening of doors.

Arrangement of pre-cooling room (with or without dehumidification of refrigeratedgoods)

Arrangement of hot air curtainEach unit will have their own defrost cycle even if they are in the same room due to thedifferent proximity to the doors.The defrost cycle has to be optimized on site by the plant contractor or operator. But it canalso be adapted optimally to the refrigeration operation by an intelligent and adaptive defrostcontrol system, especially for changing intervals of charging and withdrawal. All controldevices, that regulate the defrost process; have to be installed by the operator.

8.2. Defrost process

The operator is obliged to control the defrost process in such a way, that it can beensured that the defrost process is entirely completed, i.e. that there are no iceresidues in the heat exchanger coil or on any structural parts of the casing.

During at least the first five defrost phases after commissioning (stationary operation),

the operator is obliged to correct the defrost process accordingly via the controldevices by adjusting the corresponding parameters (volume flow of defrost water andtemperature) to ensure a complete defrost process.

The operator is additionally obliged to check if the defrost process is complete andthat there are no ice residues every month. An additional control is necessary if theoperating conditions for the selected defrost process has been changed.

The non-observance of these obligations leads to termination of the warranty claim.


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8.3 Visual inspection of the defrosting process

The defrost procedure has to be monitored during the first operating phases of therefrigerating installation and it has to be checked that no ice residues are left after the defrostprocess.

After the defrost process, the unit must be visually inspected to confirm that the unit has beendefrosted completely:The defrost processes have to be controlled in such a way that only frost is left on the surfaceof the heat exchanger coil.The heat exchanger coil has to be thoroughly checked for ice particles. A strong light with adirected beam of light is necessary for this inspection. A strong formation of residual ice,especially on the evaporator tubes, can destroy the heat exchanger coil and can lead torefrigerant leaks!The space below the heat exchanger coil and the tray also need to be free of any ice.

The defrosting process must be completed in the maximum defrost time. If necessary,

contact the manufacturer.If the humidity in the casing is too high after the defrost process (vapor or increased

formation of condensate on the inside walls of the casing) the defrost temperature has to bedecreased, but only so far that a complete defrost process is still guaranteed. Too muchhumidity can reduce the life of the bearings and electrical parts.

Note: All of the information in this manual is subject to technical amendment without priornotice.

Documents

GGHN Installation and Maintenance Manual