Installation
34
SS-SVX002B-EN
7. While monitoring the pressure, take a sub-cooling
temperature reading on the output side of the
condenser. The sub-cooling temperature should be 10-
20°F.
8. If necessary, (slowly) add liquid refrigerant to the
suction side to achieve the correct sub-cooling
temperature.
Note:
Remove the blockage from the air intake of the
condenser.
Fill out the applicable sections of the Warranty
Registration and Start-Up Checklist.
-20ºF Variable Speed Control
The following instructions are for charging systems with
condenser variable fan speed control using R-410A
refrigerant.
1. Partially block the airflow to the condenser with
cardboard to raise the discharge pressure. Allow the
discharge pressure to rise high enough to start the first
fan only, then maintain a constant pressure between
445-470 psig. This will lower the possibility of
overcharging.
CAUTION
Compressor Damage!
Failure to follow instructions below could result in
compressor failure and/or reduced compressor life. To
prevent compressor liquid slugging, only add liquid in
the suction line when the compressor is running. Use
extreme caution to meter liquid refrigerant into the
suction line slowly. If liquid is added too rapidly,
compressor oil dilution and oil pumpout could occur.
2. Slowly meter liquid refrigerant through the suction
side while watching the pressure gauges and
monitoring superheat and sub-cooling temperatures.
3. Take a superheat temperature reading near the feeler
bulb from the thermal expansion valve with the
temperature measuring device being well insulated.
The ideal superheat temperature is 12- 15°F. Maximum
allowable superheat temperature is 20°F.
4. While monitoring the pressure, take a sub-cooling
temperature reading on the output side of the
condenser. The sub-cooling temperature should be 10-
20°F.
5. If necessary, (slowly) add liquid refrigerant to the
suction side to achieve the sub-cooling temperature.
6. If the unit has hot gas reheat (optional), the previous
steps are still followed except the hot gas reheat valve
must be open to allow refrigerant to flow into the
reheat coil to obtain the proper amount of refrigerant
charge. This can be done by using the system
controller to enable a call for dehumidification (lower
the humidity set point). This process may need to be
repeated several times. After cycling the system
through the hot gas reheat cycle, recheck the system
charge with the system only in the Cooling mode.
Important:
Remove the blockage to the air intake of the
condenser.
7. Fill out the applicable sections of Warranty
Registration and Start-Up Checklist.
-30°F Ambient Applications
Note:
For units designed for -30°F operation, a receiver is
used to store the refrigerant during the time the
condenser is not utilizing the extra refrigerant
charge.
1. Follow steps 1 - 8 in
. Once superheat and sub-cooling
temperatures are stabilized, additional refrigerant
must be added to the receiver.
Note:
It is important not to exceed 80% of the total
condenser and receiver volume to allow room for
expansion.
2. The head pressure control valve setting is printed on
the side of the valve body. This setting is the lowest
head pressure that will be maintained during system
operation. It may be necessary to add additional
refrigerant to raise the head pressure to the value
printed on the valve (290 psig for R-410A).
3. If a refrigerant level sight glass is included on the side
of the receiver, it may be used to assist in charging the
air conditioning system. The proper charge can be
confirmed by viewing the level of refrigerant in the
receiver(s) while the unit is running at an elevated
discharge pressure.
4. Keep the air intake to the condenser blocked and
maintain the discharge pressure at 445 psig and hold it
constant. The condenser fan nearest the condenser
header should be operating continuously. All other
fans, if additional fans exist, should be off during this
time.
5. Add additional refrigerant charge to the receiver as
needed until the refrigerant level rises to the center of
the sight glass, indicating the receiver is 80% filled.
6. When the refrigerant in the receiver reaches the sight
glass, the unit is fully charged.
Important:
Remove the blockage to the air intake of the
condenser.
7. Fill out the applicable sections of the Warranty
Registration and Start-Up Checklist.
Refrigerant Characteristics
Pressure/Temperature Settings
The following table is provided to assist with the normal
settings of the system for R-410A refrigerant. Where
applicable, minimum and maximum settings are given
along with normal operating pressures.
