COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
Figure 10: Automatic Burner Control Sequence
Thermostat 24 V
Flue Fan
Pressure |
| P | NO |
Switch | C |
| NC |
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|
Ignition Spark
Start Gas Valve
Flame Signal
Axial Fan
Burner Sequence for Ignition Control
START | RUN | SHUT DOWN |
30 Sec. Purge* | 30 Sec. Post Purge |
ts = 10 seconds |
|
30 Sec. Delay | 90 Sec. Delay |
*Purge time begins at pressure switch change over.
Required Incoming Signals
If at any stage the flame fails, the control will retry
Signals Output By Control for ignition. The control has four trials for ignition before a one hour lockout.
Figure 11: Gas Valve for Models UHA(S) 150 - 400
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| Top View |
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| Regulator |
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End View | ½PSI |
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| C |
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| IN |
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| ON |
Gas Inlet |
| OFF | Outlet |
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| Pressure | |
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| Description |
| Part Number |
| Gas Valve 150 - 225 NG |
| 90032505 |
Inlet Pressure | Gas Valve 150 - 225 LP |
| 90032506 |
Gas Valve 250 - 400 NG |
| 90032520 | |
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| Gas Valve 250 - 400 LP |
| 90032521 |
20 |
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