PB Heat Peerless Boilers GM Series, Installation, Operation & Maintenance Manual

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20
B. SEQUENCE OF OPERATION,
INTERMITTENT IGNITION
1. Thermostat calls for heat.
2. Limit senses boiler water temperature. Prevents
operation until water temperature falls approximately
15°F (9°C) below the cut-out temperature.
3. Automatic vent damper (if used) opens. Damper
must be in open position when appliance main
burner(s) is operating.
4. Gas valve energizes.
a. Igniter on.
b. Pilot gas on, igniting pilot.
5. Pilot flame detected.
a. Igniter off.
b. Main gas on, igniting main burners.
Note: If the pilot is not detected within 90 seconds, the
igniter and pilot gas are turned off for 5 minutes. The
sequence then resumes at Step 4a.
6. Call for heat ends.
a. Pilot and main gas off, extinguishing pilot and
main burners.
b. Automatic vent damper (if used) closes.
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