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Installation, Operation and Maintenance Manual

VariCool

®

 VAV

15

Subject to change without notice.

10.20-IM (0818)

Return Air Sensor Wiring

Using a minimum 18-20 AWG 300 volt rated two conductor 

shielded cable  with drain wire make the following electrical 

connections
Note: Use a minimum two conductor cable for temperature 

only. Use a minimum five conductor for the temperature and 

humidity sensor

8� 

The supply air temperature sensor is non-polarity 

observant Connect from one NTC terminal inside the 

supply air temperature sensor to TB3-NTC

9� 

Connect the other NTC terminal inside the temperature 

sensor to TB3-NTC

10� 

Connect the drain wire to ground at the VariCool’s 

electrical control panel end only

Return Air RH Sensor (Option)

If the Return Air Sensor has the Humidity Sensor for optional 

humidity control or Airside Economizer, continue with steps 

11, 12, and 13

11� 

Connect the terminal marked G+ to terminal TB3-G+

12� 

Connect the terminal marked TB3- M to M

13� 

Connect terminal Hout to terminal TB3-Hout

Outdoor Air Sensor (Option)

The outdoor air temperature and humidity sensor is required 

for Airside Economizer function An outdoor air temperature 

sensor  is  required for the Heat Pump option The unit 

Outdoor Air Sensor must be field installed in the outdoor  air 

ducting

BE AWARE:  If  the unit has optional humidity sensor 

because of the Airside Economizer control, 

polarity must be observed when making 

electrical connections�

14� 

Cut out the mounting template provided with the 

sensor

Duct Mount Installation

15� 

Select the location to mount the sensor and drill a hole 

through the supply air duct at least ¾” in diameter

16� 

Using a 7/64” drill bit; drill the three fastening screw 

holes located on the template for the fastening ring

17� 

Remove the duct sensor’s  mounting ring from the duct 

probe and position it over the holes previously drilled in 

the duct

18� 

Use three #6 x ¾” Pan Head sheet metal screws and 

fasten bracket to the duct

19� 

Place the probe into the supply air duct

20� 

Use the screw provided to tighten the clamping ring

Outdoor Air Sensor Wiring

Using a minimum 18-20 AWG 300 volt rated two conductor 

shielded cable  with drain wire make the following electrical 

connections
Note: Use a minimum two conductor cable for temperature 

only. Use a minimum five conductor for the temperature and 

humidity sensor

21� 

The supply air temperature sensor is non-polarity 

observant Connect from one NTC terminal inside the 

supply air temperature sensor to TB4-NTC

22� 

Connect the other NTC terminal inside the temperature 

sensor to TB4-NTC

23� 

Connect the drain wire to ground at the VariCool’s 

electrical control panel end only

Return Air RH Sensor (Option)

If the Return Air Sensor has the Humidity Sensor for optional 

humidity control or Airside Economizer, continue with steps 

24, 25, and 26

24� 

Connect the terminal marked G+ to terminal TB4-G+

25� 

Connect the terminal marked TB4- M to M

26� 

Connect terminal Hout to terminal TB4-Hout

High Static Pressure Switch

The high static pressure switch is factory installed in the 

electrical control box This switch is factory wired into the 

electrical controls for alarm if a high duct pressure condition 

occurs.  Pneumatic  tubing  must  be  field  installed  from  this 

switch  to  a  location  ½  to  2/3rds  the  distance  down  the 

straightest length of the supply air duct

INFORMATION

Make certain there are no kinks in the 

pneumatic tubing

Summary of Contents for VariCool VAV

Page 1: ...VariCool VAV Installation Operation and Maintenance Manual Effective August 2018 Water Cooled and Chilled Water Variable Air Volume...

Page 2: ......

Page 3: ...ote Alarm Output Option 16 Remote Water Pump Option 16 O A Damper Control Option 16 Smoke Detector Fire Stat Option 16 Remote On Off Control Option 16 SEQUENCE OF OPERATION 16 MARVEL PLUS CONTROLLER 1...

Page 4: ...oll to the footer section or Home industry resources enter your serial number in the Serial Search field and press return to retrieve your product wiring diagram Your serial number is a combination of...

Page 5: ...tice This publication includes warnings cautions and information icons that point out safety related issues or conditions as well as other pertinent information relative to a safe installation service...

Page 6: ...ose in one or several boxes in the compressor section HANDLING Use extreme caution so that damage does not occur when moving each section to the location of installation The unit may be moved to the l...

Page 7: ...UNIT DIMENSIONS Figure 2 Unit Dimensions and Table 2 show the dimensions of each unit section Note If the System has the Water Side Economizer Coil option the unit will have a fourth section that will...

Page 8: ...8 21 TBD TBD 21 5 20 TBD 5 50 AV 10 40 AV 12 18 32 7 18 AV 16 AV 20 80 80 35 35 48 32 20 36 7 5 22 TBD TBD 21 40 TBD 5 66 AV 24 60 AV 26 44 18 AV 30 AV 32 98 100 52 62 36 30 42 11 29 1 5 97 4 80 10 5...

Page 9: ...unit the weight of each optional component must be added to the standard VariCool unit weight shown in Table 3 MODEL BLOWER lbs EVAPORATOR lbs CONDENSER lbs TOTAL lbs AVW08 588 521 592 1701 AVW10 617...

Page 10: ...ion isolator into positions shown in Figure 3 and then move the compressor and cooling coil section into the location of installation being careful not to damage the quick connect refrigerant piping 5...

Page 11: ...connect couplings as loose fittings will restrain full refrigerant flow 13 Move the Blower Section into position of installation making sure the side that the blower can be seen will mate up with the...

Page 12: ...8 10 AVW40 120 6 AVW44 132 7 AVW48 144 8 AVW52 162 10 AVW56 168 12 AVW60 180 14 Recommended Field Installed Externally Condensate Drain Connection Each VariCool unit has a condensate drain connection...

Page 13: ...und conduct must be connected from Earth Ground to the factory supplied ground lug internal to the unit SENSOR FIELD MOUNTING WIRING All sensors and optional components that must be field installed an...

Page 14: ...the drain wire to ground at the VariCool s electrical control panel end only Return Air Temperature Sensor Option The Return Air Temperature Sensor is provided for units with the Morning Warmup optio...

Page 15: ...supply air duct at least in diameter 16 Using a 7 64 drill bit drill the three fastening screw holes located on the template for the fastening ring 17 Remove the duct sensor s mounting ring from the d...

Page 16: ...he device and wired back to the VariCool s Control Panel Terminate from the device contact termination points to the factory provided terminals TB2 18 and TB2 19 Remote On Off Control Option With the...

Page 17: ...dressed Cleaning a water cooled condenser helps to improve the heat transfer rate reduce operational cost restore efficiency prolong heat exchanger life and reduce pressure drop pumping costs Deposits...

Page 18: ...fore adding grease so as not to introduce dirt into the bearing Slowly rotate the shaft while pumping it in Pump the grease in slowly so as not to blow out the bearing seal When the grease starts to s...

Page 19: ...rcular dot in the center of the sight glass If the color of this indicator is blue the refrigerant is okay When the indicator is pink or purple an abnormal condition exists servicing is required INFOR...

Page 20: ...cycles through a cool down period usually 2 3 minutes A compressor off cycle timer is included in the electrical circuit for this purpose The time delay also helps the refrigerant system pressures to...

Page 21: ...following sequence is based on the unit being controlled by a suitable room thermostat If another control type is being utilized reference the instructions for that device a Lower thermostat set point...

Page 22: ...recharge refrigerant system Check condenser for obstructions and remove Check for the required water flow through the water regulating valve and the condenser coil Manually reset thermostat With Marv...

Page 23: ...d compressor bearings Liquid slugging Excessive head pressure Ensure thermal expansion valve bulb is tight on suction line Con firm that bulb is located properly on suction line Check operation and su...

Page 24: ...d 10 Suction pressure too low Flash gas in liquid line bubbles in sight glass due to a leak Obstructed expansion valve Loss of fluid within expansion valve bulb Clogged filter drier Ice or dirt on eva...

Page 25: ...e freely Dirt or algae not allowing float to activate pump Locate and repair electrical connection problem Clean pump and float Clean pump and float 15 Condensate Pump runs with no discharge Tubing bl...

Page 26: ...de of condenser and evaporator 9 Damages resulting from I freezing of condenser water or condensate II use of corrosive water III fouling or restriction of the air water circuit by foreign material or...

Page 27: ...or like causes 10 Damages resulting from operation with inadequate or interrupted supply of air or water 11 Damages resulting from use of components or accessories not approved by United CoolAir 12 Th...

Page 28: ...ir 12 This warranty does not apply to the installation plumbing and wiring not integral to the product 13 Damages resulting from improper application or sizing of unit 14 In the event that the refrige...

Page 29: ...sories not approved by United CoolAir 12 This warranty does not apply to the installation plumbing and wiring not integral to the product 13 Damages resulting from improper application or sizing 14 Di...

Page 30: ...ooded condenser option the scroll compressors will have crankcase heaters If the outdoor ambient is 70 F or lower let the compressors sit for approximately 24 hours before proceeding 12 Record the vol...

Page 31: ...ressures on each compressor circuit are within the proper limits i 290 550 Discharge ii 100 140 psig Suction b Compressor Amperage is below the RLA Amps listed on the unit data tag i The maximum compr...

Page 32: ...act the Distributor Is the Circuit Protection the correct type and does it meet the unit data tag requirements Yes ____________ No ____________ If not correct describe what action s have been taken to...

Page 33: ..._______ F_________ F_________ F_________ Sub cooling _________ _________ Electrical Evap Motor Amps L1_____________ L2____________ L3_____________ Compressor 1 Amps L1_____________ L2____________ L3__...

Page 34: ...for approximately 24 hours before proceeding 12 Record the voltage at the unit terminals 13 If possible with the thermostat provided switch the evaporator blower to the RUN or ON position Verify that...

Page 35: ...ding to the liquid line pressure 32 Calculate and record the liquid sub cooling for each circuit by taking the difference between the liquid line temperature and the saturation temperature correspondi...

Page 36: ...Is the Circuit Protection the correct type and does it meet the unit data tag requirements Yes ____________ No ____________ If not correct describe what action s have been taken to correct Unit contr...

Page 37: ...sor 2 Suction Pressure Suction Line Temperature psi________ F_________ psi________ F_________ Saturation Temperature F_________ F_________ Suction Superheat _________ _________ Liquid Line Pressure ps...

Page 38: ...6 40 44 48 52 56 60 d G Common to all e X Indicate Voltage 3 4 or 5 3 208 230V 3 PH 4 460V 3 PH 5 575V 3 PH f A or D Indicates number of Refrigerant Circuits A Two Refrigerant Circuits D Four Refriger...

Page 39: ...Installation Operation and Maintenance Manual VariCool VAV 39 Subject to change without notice 10 20 IM 0818 NOTES...

Page 40: ...Installation Operation and Maintenance Manual VariCool VAV 40 Subject to change without notice 10 20 IM 0818 NOTES...

Page 41: ...on the compressor labor not included Maintenance items such as filters and belts are excluded under this limited warranty FACTORY TESTED All units are functionally run tested before shipment to ensure...

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