15
Changing Blower Speeds
WARNING
To avoid death or personal injury due to
electric shock, remove electrical power
from the unit before changing speed taps
on the blower motor.
Refer to the wiring diagram on the unit to verify speed
tap settings.
Blower speeds can be changed on the fan timer board.
Both heat speed and cool speed terminals are supplied
on the board along with two unused motor lead termi-
nals. (Figure 13)
3
DI
UNUSED
NEUTRAL
C
X
XFMR
SEC
MOTOR
LEADS
1
2
S
S
C
OOL
HE
AT
S
CIR BLOWER
Figure 13
Control Board (Top)
Check Limit
Check limit control operation after 15 minutes of opera-
tion 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 should continue to run briefly
until supply air temperature drops to approximately 90-
100° F.
Fan and limit controls are preset at the factory. The
control is set for the fan to go off at 90-100° F:
NOTE: If necessary, adjust fan ON/OFF settings to
obtain satisfactory comfort level. The fan comes on at
approximately 125° F.
CAUTION
This unit must not be used as a “con-
struction heater” during the finishing
phases of construction on a new struc-
ture. This type of use may result in pre-
mature failure of the unit due to extremely
low return air temperatures and expo-
sure to very dirty atmospheres.
To Turn Off Unit
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. Turn the gas control valve knob to the OFF position.
Do not force. See Figure 11.
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.
Cooling Startup
NOTE: Check all manual reset limit controls in heating
circuit if cooling mode does not operate.
Compressor Protection Devices
The PGB**C and PGD**C compressor includes compo-
nents which are designed to protect the compressor
against abnormal operating conditions.
WARNING
To avoid death or personal injury, al-
ways disconnect electrical power before
inspecting or servicing the unit. All com-
pressor protection devices reset auto-
matically, energizing the contactor and
outdoor fan.
Operating Instructions (cooling)
(NOTE: Mechanical cooling cannot be reliably provided
at ambient temperatures below 50° F.
1. Turn on the electrical power supply to the unit.
2. Place the room thermostat selector switch in the
COOL position (or AUTO if available, and if auto-
matic changeover from cooling to heating is de-
sired).
3. Set the room thermostat to the desired tempera-
ture.