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18 

 

PREPARING EQUIPMENT FOR OPERTION 

PRE-START CHECKLIST 

Is the condenser and air handler unit properly located and 
level with proper clearance? See page 4. 
Is the ductwork correctly installed? 
Is the condensate line properly sized, run, trapped, pitched 
and primed? 
Is the air filter of the correct size and number, clean and in 
place?  
Is the wiring properly sized and connected according to the 
unit wiring diagram?  
Are all wiring connections tight including those in the unit 
and compressor electrical boxes? 
Has the unit been properly grounded and fused with the 
recommended fuse size? See wiring data.   
Has the unit been leak tested? See page 14. 
Do the condenser fans and indoor blower turn free without 
rubbing and are they tight on the shafts? 
Have all of the set screws been tightened on the blower 
motor and fan? 
Has the belt tension in the blower been checked and pulley 
aligned? 
Has all work been done in accordance with applicable local 
and national codes?  
Are all covers and access panels in place to prevent air 
loss and safety hazards?  
Has the voltage been checked? See pages 10 and 11. 
Has the crankcase heater been energized for 8 hours? Be 
sure the system switch is “OFF”. 

START-UP AND REQUIRED FIELD ADJUSTMENTS 

Do not attempt to start-up system below 50°F. ambient 
temperature. 
Be sure the crankcase heater has been energized for a 
minimum of 8 hours. 
Break the vacuum with liquid R-410A. Add to the liquid line 
at the condenser until pressures are equalized.  
Turn system switch on and operate unit. Now add 
refrigerant vapor in the suction side until the liquid sight 
glass is clear of bubbles. It is recommended the system be 
charged initially by clearing the sight-glass. Do not 
overcharge, verify subcooling. 
On systems with optional hot gas reheat it may be 
necessary to adjust the reheat thermostat to 50 degrees F. 
This setting will de-energize the reheat circuit. If not 
disconnect the reheat thermostat.  
On units with tandem compressors, capacity control is 
accomplished with a adjustable pressure switch. The 
unloading pressure switch MUST be field adjusted. It 
should be set to cut in at 140 PSIG and cut out at 108 
PSIG. This will maintain a refrigerant temperature in the 
evaporator of approximately 40 degrees F. 
The hot gas bypass valve should be energized and this 
should be the maximum charge required for these units. 
Units with reheat will require additional charge for the 
reheat circuit. 

Adjusting the hot gas bypass valve. This bypass valve 
Must be field adjusted. The valve must open at 115 PSIG. 
It may be necessary to simulate a light load if the outdoor 
temperature is above 70-75 degrees F. Reduce the 
evaporator load (lower entering airflow) until the suction 
pressure lowers to the point at which bypass is desired 
(115 PSIG). If the hot gas bypass was de-energized to 
stop hot gas flow, make sure it is now energized. Turn the 
power assembly adjusting stem on top of the regulator in a 
clockwise direction until bypass occurs (you will hear the 
gas flowing or feel the hot gas line, it will be warm when 
the unit starts to bypass). 
Check or ensure suction pressure does not fall below the 
predetermined set point  (95 PSIG). A clockwise turn of the 
adjusting stem will increase the pressure setting; a 
counterclockwise turn will decrease it. Adjustments should 
be made in small increments, allowing the system to 
stabilize after each turn. Vary the evaporator load to test at 
various conditions to ensure the suction pressure does not 
drop below the predetermined setpoint. Replace the seal 
cap on the adjusting stem. 
Check the airflow by checking the external static pressure. 
Verify the airflow is within the ratings. Check blower motor 
amperage. Make adjustments as needed to ensure airflow 
is correct and to specifications. On RCA units without hot 
gas reheat, the low ambient head pressure control should 
be factory set to cut-in at 400 PSIG and cut-out at 290 
PSIG. Check calibration of this control. If trim adjustment is 
required maintain a wide differential. 
On systems with optional hot gas reheat, Verify the 
operation of the reheat system by turning the reheat 
thermostat to a temperature 5-10 degrees F. above the 
leaving air temperature. The reheat solenoid will be 
energized and will cycle as the temperature changes. Set 
the reheat thermostat at the desired leaving air 
temperature. Adjustment should also include a calibration 
check of the head pressure control for the other fan 
motor(s) .The recommended settings are to cut in at 450 
PSIG and cut-out at 375 PSIG. Disregard these steps  if 
the unit is not equipped with hot gas reheat.  These units 
utilize an electronic variable speed head pressure control 
for one condenser fan motor. It is factory set to maintain a 
minimum head pressure of 330 PSIG. For more 
information on the reheat control valve, See Supplemental 
Instructions for Hot Gas Reheat. Readjust the reheat 
thermostat to 65-70 degrees F. The hot gas reheat circuit 
should be energized. Again clear the sight glass. This 
would be the maximum charge required for this system. 
The final adjustment of the refrigerant charge should be by 
subcooling. The recommended subcooling at the 
condensing unit should be around 15 degrees at 75 
degrees F. and as low as 5 degrees at 105 degrees F. 
Verify proper operation of the thermostatic expansion valve 
by checking the superheat. The superheat should be 18-20 
degrees at the suction line in the condensing unit. 

Содержание RCA051

Страница 1: ...3 11 4 RCA101 V HCA101 110 5 12 1 RCA141 V HCA141 142 3 11 5 RCA171 V HCA201 187 9 14 7 RCA201 V HCA201 217 0 14 6 RCA271 V HCA271 263 2 13 9 RCA361 V HCA361 311 6 13 3 RCA421 V HCA421 395 5 12 5 95...

Страница 2: ...s of the colors used Operational failure of this unit for any reason including but not limited to mechanical or electrical failure of devices internal or external to the unit loss of fuel such as natu...

Страница 3: ...rator at the air handling unit as possible The liquid line solenoid is factory installed on units with hot gas reheat Hot Gas Bypass Circuit Provided for capacity control by maintaining a constant suc...

Страница 4: ...rive sheaves connected to a 1725 rpm motor The blower has sealed ball bearings that do not require lubrication Blower Motor The blower motor operates at 1725 rpm The motor has sealed ball bearings tha...

Страница 5: ...lectric heater may be required Air Handler Model Heater kW Available V HCA051 1 9 V HCA071 1 12 V HCA141 1 25 V HCA201 5 39 V HCA271 5 50 V HCA361 10 60 Minimum 80 CFM per kW Table 4 UNIT LOCATION Con...

Страница 6: ...unit support at mounting location Install proper electrical power service and disconnect switch Provide drainage as necessary Maintain minimum clearance for airflow into and out of unit Inspection of...

Страница 7: ...1 030 0 5 1 090 0 6 1 160 0 7 1 500 680 0 3 780 0 3 870 0 4 960 0 5 1 040 0 6 1 100 0 7 1 100 650 0 2 770 0 3 860 0 3 940 0 4 1 020 0 5 1 090 0 6 1 160 0 6 VCA HCA 1 400 700 0 3 800 0 3 880 0 4 960 0...

Страница 8: ...8 DIMENSIONS...

Страница 9: ...9 DIMENSIONS Continued...

Страница 10: ...10 DIMENSIONS...

Страница 11: ...11 DIMENSIONS Continued...

Страница 12: ...LA MCA Max Fuse Size 208 230 1 60 4 4 6 15 208 230 3 60 2 0 3 15 460 3 60 1 0 2 15 1 2 380 415 3 50 1 5 2 15 208 230 1 60 5 4 7 15 208 230 3 60 2 8 4 15 460 3 60 1 4 2 15 3 4 380 415 3 50 2 1 3 15 208...

Страница 13: ...conjunction with the control for Hot Gas Reheat A remote system switch such as a timeclock or interlock may be used to energized the controls Once it is established that supply voltage is within the u...

Страница 14: ...14 TYPICAL FIELD WIRING DIAGRAM...

Страница 15: ...r handler is installed at a higher elevation than the compressor provide a vertical loop in the suction line adjacent to the air handler to a point at least to the top of the evaporator coil Do not in...

Страница 16: ...ic acid also decomposes the compressor lubrication oil causing sludge Great care should be exercised in keeping moisture out of the refrigeration system when installing tubing because an extremely sma...

Страница 17: ...17 FIELD WIRING DIAGRAM...

Страница 18: ...ove 70 75 degrees F Reduce the evaporator load lower entering airflow until the suction pressure lowers to the point at which bypass is desired 115 PSIG If the hot gas bypass was de energized to stop...

Страница 19: ...er is applied to the high pressure control and the adjustable time delay The time delay begins when power is applied to the timer After the time delay closes the circuit continues through the low pres...

Страница 20: ...er in a commercial split system New system must be evacuated as outlined on page 14 to remove air and non condensables in the system The liquid line drier will trap any moisture left in the system Sys...

Страница 21: ...d inlet clearances and for possible air re circulation Check high side equalized pressure reading with equivalent outdoor temperature Check calibration of switch Check discharge and liquid line pressu...

Страница 22: ...on of low ambient head pressure control Suction Pressure Too Low Refrigerant undercharge Blower running backwards Loose blower pulley or belts Defective or improperly adjusted expansion valve Dirty fi...

Страница 23: ...ilter Check superheat and adjust TXV check bulb Check compressor for proper operation See above high discharge pressure Check external static pressure Supply Air Temperature Too Low Airflow is too low...

Страница 24: ......

Страница 25: ...__________ WB _________ Design CFM ________________ Outdoor Air Inlet Temperature _____________ DB__________ WB _________ Outdoor Fan Discharge Air Temperature__________ DB ________ Suction Pressure _...

Страница 26: ...26 NOTES...

Страница 27: ...27 NOTES...

Страница 28: ...28...

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