Installation Instructions

9
Fixed Orifice
1. Temporarily install a thermometer 4-6" from the compres-
sor on the suction line. Ensure the thermometer makes
adequate contact and is insulated for best possible read-
ings. Use vapor temperature to determine superheat.
2. Refer to the superheat table provided for proper system
superheat. Add charge to lower superheat or recover
charge to raise superheat.
Expansion Valve System
NOTE: Units matched with indoor coils equipped with non-
adjustable TXV should be charged by subcooling only.
1. Temporarily install a thermometer on the liquid line at the
liquid line service valve and 4-6" from the compressor on
the suction line. Ensure the thermometer makes adequate
contact and is insulated for best possible readings. Use
liquid line temperature to determine sub-cooling and va-
por temperature to determine superheat.
2. Check subcooling and superheat. Systems with TXV ap-
plication should have a subcooling of 7 to 9 ºF and super-
heat of 7 to 9 ºF.
a. If subcooling and superheat are low, adjust TXV to
7 to 9 ºF superheat, then check subcooling.
NOTE: To adjust superheat, turn the valve stem
clockwise to increase and counter clockwise to de-
crease.
b. If subcooling is low and superheat is high, add charge
to raise subcooling to 7 to 9 ºF then check super-
heat.
c. If subcooling and superheat are high, adjust TXV
valve to 7 to 9 ºF superheat, then check subcooling.
d. If subcooling is high and superheat is low, adjust
TXV valve to 7 to 9 ºF superheat and remove charge
to lower the subcooling to 7 to 9 ºF.
NOTE: Do NOT adjust the charge based on suction pressure
unless there is a gross undercharge.
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. For best
results, on outdoor units with TXVs, superheat should be 2-5°
at 4-6" from the compressor. Make final charge adjustments in
the cooling cycle.