Manual

13
I. Sequence of Operation, Continuous Ignition
(Standing Pilot).
1. Normal Operation
a. Thermostat calls for heat. Vent Damper opens.
b. Gas Valve energized allowing main gas ow and
ignition of Main Burners.
c. Call for heat ends. Gas Valve de-energized,
extinguishing main ame. Vent Damper closes.
2. Safety Shutdown
a. Limit: Automatically interrupts main burner
operation when water temperature exceeds set
point. Maximum allowable temperature is 250°F.
Circulator continues to operate with call for
heat and Vent Damper closes. Normal operation
resumes when water temperature falls below set
point.
b. Blocked Vent Switch. Automatically interrupts
main burner operation when excessive vent
system blockage occurs. Circulator continues
to operate and Vent Damper remains open with
call for heat. If blocked vent switch is activated
do not attempt to place boiler in operation. The
source of blockage must be corrected by trained
and skilled personnel from a qualied service
agency before resetting switch.
c. Flame Roll-out Switch. Automatically interrupts
boiler operation when ames or excessive heat
are present in vestibule. Circulator continues to
operate and Vent Damper remains open with call
for heat. Control is single use device. If ame
roll-out switch is activated do not attempt to
place boiler in operation. The source of blockage
must be corrected and the ame roll-out switch
replaced by trained and skilled personnel from a
qualied service agency.
d. Thermocouple: senses pilot ame and causes gas
valve to turn off main burner and pilot burner
gas ow should pilot burner ame extinguish.
Circulator continues to operate and Vent Damper
remains open with call for heat.
Figure 12: Wiring Diagram, Continuous Ignition (Standing Pilot)