Specifications
9
2-Stage Application
Run the condensing unit on low-stage cooling for 10 minutes
until refrigerant pressures stabilize. Follow the guidelines and
methods below to check the unit operation and ensure that the
refrigerant charge is within limits. Charge the unit on low stage.
1. Purge the gauge lines.
2. Connect the service gauge manifold to the base-valve service
ports.
3. Run the system at least 10 minutes to allow the pressure to
stabilize.
4. Temporarily install a thermometer on the liquid (small) line
near the liquid line service valve with adequate contact.
Insulate the thermometer for the best possible reading.
5. Check the subcooling and superheat. Systems with TXV
application should have a subcooling of 5ºF to 7ºF and
superheat of 7ºF to 9ºF.
■ If the subcooling and superheat are low, adjust TXV to 7ºF
to 9ºF superheat. Check subcooling.
NOTE: To adjust the superheat, turn the valve stem
clockwise to increase and counterclockwise to decrease.
■ If the subcooling is low and the superheat is high, add
charge to raise the subcooling to 5ºF to 7ºF. Check
superheat.
■ If subcooling and superheat are high, adjust TXV valve to
7ºF to 9ºF superheat. Check subcooling.
■ If subcooling is high and superheat is low, adjust TXV
valve to 7ºF to 9ºF superheat and remove charge to lower
the subcooling to 5ºF to 7ºF.
NOTE: Do not adjust the charge based on the suction
pressure unless there is a gross undercharge.
6. Disconnect manifold set, installation is complete.
Subcooling = Saturated Liquid Temperature - Liquid Line
Temperature
NOTE: Check the Schrader ports for leaks and tighten valve
cores if necessary. Install caps finger tight.
Heat Pump—Heating Cycle
The proper method of charging a heat pump in the heat mode is
by weight with the additional charge adjustments for line size, line
length and other system components. Make final charge
adjustments in the cooling cycle.
NOTE: Subcooling = Saturated Liquid Temperature - Liquid Line Temperature
Saturated Suction Pressure Temperature
Suction Pressure Saturated Suction Temperature ºF Suction Pressure Saturated Suction Temperature ºF
PSIG R-410A PSIG R-410A
50 1 78 20
52 3 80 21
54 4 85 24
56 6 90 26
58 7 95 29
60 8 100 31
62 10 110 36
64 11 120 41
66 13 130 45
68 14 140 49
70 15 150 53
72 16 160 56
74 17 170 60
76 19