S
EQUENCE OF OPERATION FOR SENTRY BOILERS
EQUIPPED WITH CONTINUOUS BURNING PILOTS
F
OR DIAGRAMS SHOWN ON PAGE 14.
13
Sentr y
LIGHTED PILOT HEATS THERMOCOUPLE AND KEEPS PILOTSTAT OPEN.
THERMOSTAT CALLS FOR HEAT
HIGH LIMIT CONTACTS CLOSED?
LOW WATER CUT-OFF (WHEN USED)
CONTACTS CLOSED?
VENT DAMPER RELAY ENERGIZED.
VENT DAMPER MOTOR OPENS VENT DAMPER.
END SWITCH CLOSES.
MAIN VALVE OPERATOR OPENS.
LIGHTED PILOT IGNITES MAIN BURNERS.
IF PILOT SHOULD BLOW OUT, THERMOCOUPLE
WILL SHUT OFF MAIN BURNER.
WHEN THERMOSTAT IS SATISFIED, OR WHEN HIGH LIMIT
OR LOW WATER CUT-OFF CONTACTS ARE OPEN, MAIN
VALVE OPERATOR CLOSES.
VENT DAMPER CLOSES. CIRCULATOR OFF.
SYSTEM GOES TO STANDBY WITH LIGHTED PILOT.
CIRCULATOR ENERGIZED
(IF COMBINATION AQUASTAT
CONTROL USED)
NO FURTHER
A
CTION
SEQUENCE OF OPERATION FOR SENTRY BOILERS EQUIPPED WITH HONEYWELL INTERMITTENT
IGNITION SYSTEM (IID) FOR DIAGRAMS SHOWN ON PAGE 15.
THERMOST
A
T CALLS FOR HEA
T
HIGH LIMIT CONTACTS CLOSED?
LO
W
W
A
TER CUT
-OFF (WHEN USED)
CONTACTS CLOSED?
VENT DAMPER RELAY ENERGIZED.
VENT DAMPER MOTOR OPENS VENT DAMPER.
END SWITCH CLOSES.
IGNITION CONTROL ENERGIZED
THE PILOT FLAME ESTABLISHED ?
SPARK GENERATOR OFF. MAIN VALVE
OPERATOR OPENS. MODULE MONITORS
PILO
T FLAME.
WHEN THERMOSTAT IS SATISFIED OR WHEN HIGH LIMIT OR LOW WATER CUT-OFF CONTACTS ARE OPEN, VALVE OPERA-
TORS CLOSE. PILOT & MAIN BURNERS OFF. VENT DAMPER CLOSES. CIRCULATOR OFF. SYSTEM GOES TO STANDBY.
SPARK GENERATOR MODULE POWERED.
S8600F OR S8600M: IGNITION SPARK STARTS AND PILOT VALVE OPERATOR OPENS.
S8670E: IGNITION SPARK AND PILOT VALVE OPERATOR DELAYED FOR 30-70 SECONDS.
L.P.PROPANE GAS (S8600M & S8670E)
IGNITION TRIAL CONTINUES FOR 90 SEC-
ONDS. AFTER TRIAL FOR IGNITION, SYS-
TEM SHUTS OFF. AFTER 5 MINUTES MOD-
ULE RE-INSTATES TRIAL FOR IGNITION. IF
PILOT FLAME NO
T ESTABLISHED, IGNI-
TION TRIAL, SYSTEM SHUT-OFF AND 5
MINUTES WAIT SEQUENCE REPEATS
CONTINUOUSL
Y.
NA
TURAL GAS (S8600F) IGNI
-
TION SPARK CONTINUES.
PILO
T VALVE REMAINS OPEN
UNTIL SYSTEM IS RESET.
CIRCULATOR ENERGIZED
(IF COMBINA
TION A
Q
U
AST
A
T
CONTROL USED)
NO FURTHER
ACTION
NO
YES
NO
YES
NONO
YES