Final Charge Adjustment; Fixed Orifice; Expansion Valve System; Heat Pump - Heating Cycle - Goodman CONDENSING UNIT Installation & Service Reference

NOTICE
Violation of EPA regulations may result in fines or other
penalties.
CAUTION
Operating the compressor with the suction valve closed will
void the warranty and cause serious compressor damage.

Final Charge Adjustment

The outdoor temperature must be 60°F or higher. Set the
room thermostat to COOL, fan switch to AUTO, and set the
temperature control well below room temperature.
Purge gauge lines. Connect service gauge manifold to base-
valve service ports. Run the system (on low stage for two-
stage units) for 10 minutes to allow pressures to stabilize,
then check subcooling and/or superheat as detailed in the
following sections.
Superheat = Suct. Line Temp. - Sat. Suct. Temp.
Subcooling = Sat. Liquid Temp. - Liquid Line Temp.
CAUTION
To prevent personal injury, carefully connect and disconnect
manifold gauge hoses. Escaping liquid refrigerant can cause
burns. Do not vent refrigerant into the atmosphere. Recover
all refrigerant during system repair and before final unit
disposal.

Fixed Orifice

1. For best results, temporarily install a thermometer on
the suction line near the compressor. The thermometer
should be located within 4" to 6" of the compressor. En-
sure the thermometer makes adequate contact and is
insulated.
NOTE: An optional method is to locate the thermometer
at the suction line service valve. Ensure the thermom-
eter makes adequate contact and is insulated.
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

Single Speed Application
1. Temporarily install thermometer on both liquid (smaller)
and vapor (larger) lines near service valves. Ensure ad-
equate contact and insulate sensors well for best pos-
sible reading. Use liquid temperature to determine sub-
cooling and vapor temperature to determine superheat.
2. Check subcooling and superheat. Systems with TXV ap-
plication should have a subcooling of 5 to 9 ºF and su-
perheat 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 5 to 9ºF 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 5 to 9ºF.
NOTE: Do NOT adjust the charge based on suction pres-
sure unless there is a gross undercharge.
Two Speed Application
1. Temporarily install thermometer on both liquid (smaller)
and vapor (larger) lines near service valves. Ensure ad-
equate contact and insulate sensors well for best pos-
sible reading. Use liquid temperature to determine sub-
cooling and vapor temperature to determine superheat.
2. Check subcooling and superheat. Systems with TXV ap-
plication should have a subcooling of 5 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 5 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 5 to 9 ºF.
NOTE: Do NOT adjust the charge based on suction pres-
sure 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. Make final
charge adjustments in the cooling cycle.
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