2.Check for correct manifold gas pressures. See “Checking Gas Input”.
3.Check the supply gas pressure. It must be within the limits shown on rating nameplate. Supply pressure should be checked with all gas appliances in the building at full fire. At no time should the standby gas line pressure exceed 10.5", nor the operating pressure drop below 4.5" for natural gas units. If gas pressure is outside these limits, contact the lo- cal gas utility for corrective action.
MANIFOLD GAS PRESSURE ADJUSTMENT
Small adjustments to the gas flow may be made by turning the pressure regulator adjusting screw on the automatic gas valve. Refer to Figure 6.
M A N U A L | G A S |
S W I T C H |
|
( S H O W N | I N " O F F |
P O S I T I O N )
M A N I F O L D
P R E S S U R E
T A P
C O N T R O L
E L E C T R I C A L
C O N N E C T I O NG R O U N D
T E R M I N A L
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.
HOT SURFACE38 PILOT INSTRUCTIONS
To check, adjust or remove the hot surface pilot assembly,
CLOSE THE MAIN MANUAL
The pilot flame should envelope 38 inch of the end of the flame sensor and not contain any yellow color, see Figure 7.
3 / 8
1 / 2 - 1 4 N P T
( O U T L E T ) FIG. 7 - PROPER FLAME ADJUSTMENT
To adjust the pilot flame:
P I L O T G A S
C O N N E C T I O N
P I L O T
A D J U S T M E N T
1.Remove the pilot adjustment cover screw.
2.Adjust the pilot adjustment screw to achieve the proper pi- lot flame.
L I N E P R E S S U R E | T A P 3. | Replace the pilot adjustment cover screw after the pilot | ||
|
|
| flame is set. | |
|
| To remove the hot surface pilot assembly: | ||
|
| 1. | Disconnect the wiring from the gas valve to the hot surface | |
M A N I F O L D P R E S S U RpilotE assembly. | ||||
A D J U S T M E N T |
| 2. | Remove the two (2) #8 screws holding the hot surface pilot | |
( R E M O V E C A P ) | ||||
|
| |||
|
|
| assembly in place. | |
1 / 2 - 1 4 N P T |
| 3. | Remove the hot surface pilot assembly. | |
( I N L E T ) |
|
|
| |
V E N T P R E S S U R E L I M I T E R |
| To remove the hot surface ignitor and flame sensor assembly: | ||
FIG. 6 - GAS VALVE |
| 1. | Remove the clip attaching the ignitor and sensor assembly | |
|
|
as shown in Figure 8.
Adjust as follows:
1.Remove the cap from the valve body. See Figure 6 for loca- tion.
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 0.2. The correct manifold pressure for pro- pane (LP) is 10.0 IWG 0.2.
BURNER INSTRUCTIONS
To check or change the burners, CLOSE THE MAIN MANUAL
1.Remove the two (2) #8 screws holding each burner in place.
FIG. 8 - IGNITOR AND FLAME SENSOR ASSEMBLY
2.Lift the pilot and sensor from the assembly. Care must be taken not to damage the pilot or sensor when removing this assembly.
10 | Unitary Products Group |