Burnham 805B, Installation, Operating And Servicing Instructions, Page: 54 / 100

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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 flame is proven, the ignition
terminal (10) is de-energized and the main
valve terminal (9) is energized, allowing main
gas flow 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 flames. "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 flue 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 flames
or excessive heat are present in vestibule.
Circulator continues to operate with call for
heat. Control is single use device. If flame
roll-out switch is activated, do not attempt to
place boiler in operation. Correct cause of
spillage and replace flame roll-out switch.
iv . RM7890A Burner Control: Automatically
interrupts main burner operation if a pilot
flame is not detected during the four or ten
second pilot flame 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.