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6. Electronically Supervised Intermittent Ignition
(EP/EP-CSD-1) Sequence of Operation
a. Normal Operation
i. Thermostat or operating control calls for
heat.
ii. Terminal #6 of RM7890A Burner Control
is energized, initiating a microcomputer
monitored circuit test.
iii. The pilot valve (terminal 8) and ignition
transformer (terminal 10) are energized.
The pilot valve opens and the ignition
electrode sparks, igniting the pilot.
iv. After the pilot ame is proven, the ignition
terminal (10) is de-energized and the main
valve terminal (9) is energized, allowing
main gas ow and ignition of main burners.
“Main” gas light will be illuminated.
v. When the call for heat ends, terminal #6
is de-energized, extinguishing the pilot
and main ames. “Main” gas light is de-
energized.
b. Safety Shutdown
i. 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. Normal operation
resumes when water temperature falls below
set point.
ii. Blocked Vent Switch: Automatically
interrupts main burner operation when
excessive ue gas spillage occurs.
Circulator continues to operate with call for
heat. If blocked vent switch is activated,
do not attempt to place boiler in operation.
Correct cause of spillage and reset blocked
vent switch.
iii. Flame Roll-out Switch: Automatically
interrupts main burner operation when
ames or excessive heat are present in
vestibule. Circulator continues to operate
with call for heat. Control is single use
device. If ame roll-out switch is activated,
do not attempt to place boiler in operation.
Correct cause of spillage and replace ame
roll-out switch.
iv. RM7890A Burner Control: Automatically
interrupts main burner operation if a pilot
ame is not detected during the four or ten
second pilot ame establishing period. The
RM7890A will lockout or recycle based
on jumper settings. “Alarm” light will be
illuminated. Refer to instructions supplied
with RM7890A for additional control
information.