Burnham 805B, Installation, Operating And Servicing Instructions, Page: 41 / 100

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2. Electronically Supervised Standing Pilot (OP)
Sequence of Operation
a. Normal Operation
i . Thermostat or operating control calls for
heat.
ii . Terminal #6 of RM7890C Burner Control is
energized, initiating a microcomputer
monitored circuit test.
iii . Pilot Flame Establishing Period (PFEP)
begins.
iv . After pilot flame is proven, terminal #9 of
RM7890C is energized, allowing main gas
flow and ignition of main burners. "Main"
gas light will be illuminated.
v . Call for heat ends. Terminal #6 of RM7890C
is de-energized, in turn de-energizing gas
valves and extinguishing main flame.
"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 . RM7890C 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
RM7890C will lockout or recycle based on
jumper settings. "Alarm" light will be
illuminated. Refer to instructions supplied
with RM7890C for additional control
information.
3. Electronically Supervised Standing Pilot (OP-CSD-1)
Sequence of Operation
a. Normal Operation
i . Thermostat or operating control calls for
heat.
ii . Terminal #6 of RM7890C Burner Control is
energized, initiating a microcomputer
monitored circuit test.
iii . Pilot Flame Establishing Period (PFEP)
begins.
iv . After pilot flame is proven, terminal #9 of
RM7890C is energized, allowing main gas
flow and ignition of main burners. "Main"
gas light will be illuminated.
v . Call for heat ends. Terminal #6 of RM7890C
is de-energized, in turn de-energizing gas
valves and extinguishing main flame.
"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 . RM7890C 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
RM7890C will lockout or recycle based on
jumper settings. "Alarm" light will be
illuminated. Refer to instructions supplied
with RM7890C for additional control
information.
v. Pilot Safety Switch: Automatically de-
energizes main gas valve and interrupts pilot
gas supply if pilot flame is not detected at
any time.