16
NOTE:
Heating airflow must be adjusted to provide the temperature rise shown on rating plate. Blower speeds are programmed to
deliver adequate airflow at rated external static pressure (ESP). Refer to airflow table provided in the
Appendix
for details.
Limit Check
Check limit control operation after 15 minutes of operation by blocking the
return air grille(s).
1. After several minutes the main burners must go OFF. Blower will continue to
run.
2. Remove air restrictions and main burners will relight after a cool down
period of a few minutes.
Adjust the thermostat setting below room temperature.
1. Main burners must go OFF.
2. Circulating Air Blower will continue to run for 90, 120, 150 or 180 seconds,
depending on the setting.
NOTE:
If necessary, adjust fan OFF delay settings to obtain satisfactory comfort
level.
Unit Shutdown
1. Set the thermostat to lowest setting.
2. Turn off the electrical power supply to the unit.
3. Remove the heat exchanger door on the side of the unit
by removing screws.
4. Move the gas control valve switch to the OFF position. Do
not force.
5. Close manual gas shutoff valve external to the unit.
6. Replace the heat exchanger door on the unit.
7. If cooling and/or air circulation will be desired, turn ON
the electrical power.
C
OOLING
S
TARTUP
NOTE:
Check all manual reset limit controls in heating circuit if
cooling mode does not operate.
Compressor Protection Devices
The compressor includes components which are designed to
protect the compressor against abnormal operating conditions.
Cooling Refrigerant Charging (Models with TXV)
Check unit charge before putting the cooling section into full operation.
The unit has a thermostatic expansion valve metering device. To ensure the
unit is properly charged for the intended application, check the unit
refrigerant sub-cooling at the condenser. The refrigerant sub-cooling is a
function of outdoor ambient temperature and return air temperature of
the conditioned space. It is the installing contractors responsibility to ensure
the proper refrigerant sub-cooling at the condenser is adjusted for each
application. As the outdoor ambient temperature rises the sub-cooling
decreases and as the outdoor ambient temperature lowers, the sub-cooling
increases.
NOTE:
Proper sub-cooling adjustment optimizes cooling
performance. Models equipped with thermostatic expansion valve, charge
the system to sub-cooling, range shown on chart, when necessary, adjust
expansion valve stem for superheat setting.
NOTE:
The expansion valve will not need adjustment for most applications.
Ensure system superheat is set within range listed on chart.
Superheat Adjustment
To adjust superheat, remove the control box cover and locate the expansion valve on the liquid line of the evaporator. 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. Replace adjustment cap. Wait a minimum of 10 minutes between adjustments to allow time for the TXV
and pressures to stabilize.
LO COOL
HI COOL
LO HEAT
HI HEAT
U6
U7
U4
U5
U3
K2
K1
P1
ECON
STAGE
DELAY
SPEEDUP
SW1
FAULT
RECALL
BLOWER
OFF DELAY
F1
R
C W1 W2
G Y1 Y2
Control Board (Top)
Models #
Superheat °F
Subcooling °F
GPG1624060M41
9 - 13
9 - 13
GPG1630080M41
8 - 12
10 - 14
GPG1636080M41
10 - 14
8 - 12
GPG1642100M41
10 - 14
6 - 10
GPG1648100M41
8 - 12
8 - 12
Design superheat & subcooling
@ 95 °F outdoor ambient temperature
