14
Superheat Adjustment
NOTE: Superheat adjustments should not be made
until indoor ambient conditions have stabilized.
This could take up to 24 hours depending on
indoor temperature and humidity. Before checking
superheat, run the unit in cooling for 10-15
minutes or until refrigerant pressures stabilize.
Use the following guidelines and methods
to check unit operation and ensure that the
refrigerant charge is within limits.
For TXV systems, to adjust superheat, unscrew the
cover from the expansion valve, locate the adjustment
screw, and turn it clockwise (in) to increase superheat
or counterclockwise (out) to decrease superheat. It is
recommended to make small adjustments at a time, 1/8-1/4
turn increments. Replace adjustment cap. Wait a minimum
of 10 minutes between adjustments to allow time for the
TXV and pressures to stabilize.
Refrigerant Charge Check
NOTE: For optimal performance, follow charging
instructions below.
Units with Fixed Orifice Devices
All package units with fixed orifice devices are charged
using the superheat method at the compressor suction line.
To increase super heat, remove charge and to decrease
super heat, add charge. After superheat is adjusted, it is
recommended to check unit subcooling at the condenser
coil liquid line. See Figure 13 - Design Superheat and
Subcooling table for targets on each model.
Units with Expansion Valve (TXV)
Single Stage Cooling Application:
Refer to the Design
Superheat & Subcooling table.
Two Stage Cooling Application:
Run unit on Low Stage
cooling and refer to Design Superheat & Subcooling table.
1. Purge gauge lines. Connect service gauge manifold
to access fittings. Run system at least 10 minutes to
allow pressure to stabilize.
2. Temporarily install thermometer on liquid (small) line
near liquid line access fitting with adequate contact
and insulate for best possible reading.
3. Check subcooling and superheat. System should
have a subcooling and superheat within the range
listed on the Design Superheat and Subcooling table.
a. If subcooling and superheat are low, adjust TXV
superheat, then check subcooling.
NOTE:
To adjust superheat, turn the valve stem
clockwise to increase and counterclockwise to
decrease.
b. If subcooling is low and superheat is high, add
charge to raise subcooling then check superheat.
c. If subcooling and superheat are high, adjust TXV
valve superheat, then check subcooling.
d. If subcooling is high and superheat is low, adjust
TXV valve superheat and remove charge to lower
the subcooling.
NOTE:
Do NOT adjust the charge based
on suction pressure unless there is a gross
undercharge.
4. Disconnect manifold set, installation is complete.
Model
Superheat
± 2
o
F
Subcooling
± 1
o
F
Expansion
Device
Cooling
Stage
Outdoor
Ambient
(
o
F)
GPHM52441
10
6
TXV
Low
82
GPHM53041
5
9
TXV
Low
82
GPHM53641
11
7
TXV
Low
82
GPHM54241
8
7
TXV
Low
82
GPHM54841
8
9
TXV
Low
82
Design Superheat & Subcooling
Design Superheat and Subcooling
Figure 13
ELECTRICAL HEAT INSTALLATION &
ADJUSTMENT
Heater Kit
NOTE: A separate power supply is required for
HKR/HKP Heater Kits.
Refer to the specification manual for heater kit match up
and Heater Kit Electrical Data.
This series of electric cooling and, heat pump package
equipment is designed to accept a field installed electric
heat kit. The unit is equipped to easily install the HKP or
HKR Series Electric Heat Kit. Full Installation Instructions
are included in this kit. Please use this document for
guidance in field equipping the package unit with electric
heat.
Choose the heat kit that fits the application for the specific
installation. Permanently mark the unit’s nameplate
with the model being installed. High and low voltage
connections are detailed in the heat kit instructions.
Indoor Blower motor speed tap selection may need to be
modified to accommodate normal continuous operation to
prevent a nuisance trip. See following Figure 14 - Electric
Heat KW.
