Detailed Sequence Of Operation - UTICA BOILERS UB90 125 Installation Manual And Operating Instructions

XV. DETAILED SEQUENCE OF OPERATION
POWER ON
STAND BY
THERMOSTAT
CALLS FOR HEAT
CIRCULATOR
ENERGIZES THRU
2K1 CONTACTS
IBC SELF CHECK OF
INTERNAL CIRCUITRY
1-2 SEC
IBC
CHECKS
N.O. AIR
PRESSURE
SWITCH
CONTACTS
OPEN
DRAFT INDUCER
ENERGIZES THRU
1K1 CONTACTS
IBC
WAITS FOR
UP TO 5 MINUTES
CLOSED FOR AIR PRESSURE
SWITCH CONTACTS TO CLOSE
INDICATING FAN
SUCTION
PRESENT
OPEN
CONTROL LOCKOUT. PURGE LIGHT
BLINKS. MANUAL RESET IS REQUIRED OR
CONTROL WILL AUTOMATICALLY RESET
AFTER 15 MINUTES. CIRCULATOR
REMAINS ENERGIZED AS LONG AS
THERMOSTAT CONTINURES TO CALL FOR
HEAT
PURGE LIGHT IS ON. AIRFLOW PROVED.
DRAFT INDUCER RUNS FOR 15 SEC. PREPURGE
FALSE
POSITIVES
PROOF OF
CLOSED
AIRFLOW. IBC WAITS
FOR 45 SEC
FOR AIR PRESSURE
SWITCH CONTACTS
TO OPEN
DURING THE LAST 2 SEC OF THE 5 SEC IGNITION
TRIAL, MAIN BURNER FLAME IS PROVED BY FLAME
RECTIFICATION. A FLAME SIGNAL TO IBC. GAS VALVE
IS TURNED OFF TO THE HOT SURFACE IGNITER.
IGNITION. BLUE ORANGE GLOW OF THE BURNER
PURGE LIGHT GOES OUT. HOT SURFACE IGNITER
ORANGE GLOW OF THE HOT SURFACE IGNITER
28
IF MAIN BURNER DOES NOT PROVE
FLAME IN 3 TRIALS, CONTROL
LOCKOUT. VALVE/FLAME LIGHT BLINKS.
MANUAL RESET IS REQUIRED OR CONTROL
WILL AUTOMATICALLY RESET AFTER 1 HOUR.
THIS PROBLEM IS A RESULT OF NOT
ESTABLISHING FLAME SIGNAL.
CONTROL WILL ATTEMPT 2
ADDITTIONAL IGNITION SEQUENCES.
STARTING WITH PREPURGE.
CLOSED
FLAME WITHIN INITIAL
OPEN
REMAINS ENERGIZED. BOILER RUNS.
2 SEC INTO THE 6 SEC IGNITION TRIAL POWER
IGNITER LIGHT IS OFF.
GAS VALVE OPENS FOR 6 SEC. TRIAL FOR
CAN BE SEEN THRU OBSERVATION PORT.
GAS VALVE ENERGIZED THRU 3K1 AND 4K1
CONTACTS. VALVE LIGHT IS ON.
POWERED THRU 5K1 5K2 CONTACTS FOR 20
SEC. IGNITER WARMUP. BRIGHT YELLOW
CAN BE OBSERVED THRU THE OBSERVATION
PORT IN FRONT OF BOILER SECTION JUST
ABOVE IGNITER. IGNITOR LIGHT IS ON
NO
DOES
MAIN
BURNER PROVE
YES
NORMAL
OPERATION
TRIAL FOR
IGNITION
PERIOD?