24
CASTING TEMPERATURE SAFETY SWITCH
CONTACTS WILL OPEN BREAKING 24 VOLT POWER
TO IBC. POWER INDICATOR LIGHT GOES OUT.
REQUIRES MANUAL RESET TO RE-CLOSE
CONTACTS
POWER LIGHT GOES OUT.
IF BOILER WATER TEMPERATURE REACHES
HI LIMIT (AQUASTAT) SETPOINT, HI LIMIT
N.C. CONTACTS OPEN IMMEDIATELY,
CLOSING GAS VALVE. (VALVE LIGHT GOES OUT)
IF AN ESTABLISHED FLAME SIGNAL IS LOST
WHILE CONTROL EXPECTS THAT THE BURNER
IS OPERATING, CONTROL WILL IMMEDIATELY
DE-ENERGIZE GAS VALVE. (VALVE LIGHT GOES OUT)
IF COMBUSTION AIRFLOW IS LOST WHILE BURNER
IS FIRING ( DIFFERENTIAL AIR PRESSURE
SWITCH CONTACTS OPEN) GAS VALVE WILL
BE DE-ENERGIZED. (VALVE LIGHT GOES OUT)
IF AIRFLOW DOES NOT RE-ESTABLISH, CONTROL WILL
LOCKOUT - PROBLEM WITH COMBUSTION AIRFLOW.
PURGE LIGHT BLINKS. CONTROL WILL AUTOMATICALLY
RESET AFTER 15 MINUTES
LOSS OF FLAME SIGNAL
DRAFT INDUCER RUNS THRU 30 SECOND POST
PURGE
LOSS OF COMBUSTION AIRFLOW
CONTROL WILL ATTEMPT TO RE-LIGHT BOILER
3 TIMES. IF FLAME IS NOT PROVEN. CONTROL
LOCKOUT - PROBLEM ESTABLISHING A FLAME
SIGNAL. VALVE LIGHT IS BLINKING.
DRAFT INDUCER RUNS THRU 30 SECOND POST
PURGE
IF CALL FOR HEAT REMAINS, IBC WAITS
5 MINUTES FOR AIRFLOW TO BE RE-ESTABLISHED
HI LIMIT CONTROL
DRAFT INDUCER CONTINUES TO RUN FOR 30
SECOND POST PURGE AND SWITCH OFF.
CIRCULATOR RUNS AS LONG AS THERMOSTAT
CALLS FOR HEAT.
WHEN HI LIMIT CONTACTS REMAKE BEFORE END
OF CALL FOR HEAT - CONTROL GOES INTO
A NORMAL LIGHT OFF SEQUENCE
CIRCULATOR PUMP
CIRCULATOR WILL BE ENERGIZED AS LONG AS
THERMOSTAT CALLS FOR HEAT DURING LOCKOUT
RECOVERY FROM ANY LOCKOUT REQUIRES RESET
WHICH IS ACCOMPLISHED BY REMOVING AND
REAPPLYING THE THERMOSTAT CALL FOR HEAT
OR POWER TO CONTROL
IF BURNER OPERATES WHEN BOILER HAS NO
WATER, ALUMINUM BOILER SECTIONS
HEAT UP RAPIDLY.
CASTING TEMPERATURE SAFETY SWITCH
A06102
Fig. 22
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Safety Sequences During Operation
