437758-YIM-A-0409
Johnson Controls Unitary Products
29
Figure 14: Single Stage Gas Valve Front
Figure 15: Two Stage Gas Valve Front
Figure 16: Single Stage Gas Valve Rear
Figure 17: Two Stage Gas Valve Rear
Adjust as follows:
1.
Remove the cap from the valve body. See Figures 14 and
15 for location.
2.
To decrease the gas pressure, turn the adjusting screw
counterclockwise.
3.
To increase the gas pressure, turn the adjusting screw
clockwise.
NOTE:
The correct manifold pressure for natural gas furnaces
is 3.5 IWG high heat and 1.5 IWG low heat. The correct
manifold pressure for propane (LP) is 10.0 IWG high
heat and 4.5 IWG low heat.
Burner Instructions
To check or change the burners, CLOSE THE MAIN MANUAL
SHUT-OFF VALVE AND SHUT OFF ALL POWER TO THE
UNIT.
1.
Remove the two (2) #8 screws holding each burner in place.
2.
Remove the burner assembly from the manifold assembly
by moving the burner assembly forward, turn at an angle
and pull back.
3.
Burners are now accessible for service.
Pilot Instruction
To adjust the pilot flame:
Figure 18: Proper Flame Adjustment
Manual
Gas Switch
Pilot
Adjustment
(Remove Cap)
Pilot Gas
Connection
(1/4” Compression)
1/2” NPT
(Outlet)
Outlet Pressure
Tap (1/8” NPT)
Electrical
Connection
Hi Fire
(2nd Stage)
Manifold Pressure
Low Fire
(1st Stage)
Manifold Pressure
Adjustment
Electrical
Connection
½
NPT
(Outlet)
Manifold
Pressure
Tap
Pilot
Gas
Connect
Pilot
Adjustment
(Remove Cap)
Manual
Gas
Switch
Manifold Pressure
Adjustment
(Under Cap)
1/2” NPT
(Inlet)
Line Pressure
Tap (1/8” NPT)
Line Pressure
Tap
½
NPT
(Inlet)
8
3
"
Pilot
Spark Ignitor
Flame Sensor
min.
