3
SECTION 1: OPERATION
AMBER Part of 115V ON-OFF rocker switch
LIGHT (SW1). Side of electric box (AM-100 and
AM-150). Front top of boiler (AM-300). Lit
when switch is on.
RED Top of electric box (AM-100 and AM-150).
LIGHT Front top of boiler (AM-300). Lit when
all operational controls are calling for heat
and 24V is supplied to the GC-4A ignition
control.
GREEN Top of electric box (AM-100 and 150).
LIGHT Front top of boiler (AM-300). Lit when
gas valve is energized (24V).
BOILER OPERATING LIGHTS
GC-4A On GC-4A ignition control - visible thru a
LIGHT cutout in control cover near the 6-pin
Molex connector. OFF when no 24V to
control (no call for heat). Lit when boiler is
running,GC-4Aisinignitionsequenceoron
“hold” - refer to operating sequence.
“Blinking” when GC-4A is in “lockout” or in
the middle of a retrial period.
LAMP Red and green bulbs can be checked with
CHECK Volt/ohm meter: disconnect the lamp from
the circuit and check across the leads for
continuity. Replace any burned out lights
or loose wiring.
SEQUENCE OF OPERATION (WITH LIGHTS)
1. GasOn/PowerOn. WithRockerswitchSW1(On/Off
switch) closed (amber light is ON) 115/24V
transformer is powered. Refer to figure 1, 2 or 3
for boiler wiring diagrams.
2. Boilerthermostatcallsforheat;“T-T”contactsCLOSE;
and circulator relay R1 (AM-100 and AM-150 only)
is energized. The circulator relay contacts
(C1R1) close starting the circulator pump
(AM-100/-150).
3. 24 volts is also supplied to the high limit. If the
limit (automatic reset type) is “OPEN” (Red Light
OFF) due to high water temperature, the ignition
controlwaits until limitcloses. When thelimit closes
(Red Light ON), the GC-4A ignition control is
energized (GC-4A Light ON) and checks the
position of the Combustion Prove Switch (PS1)
contacts (N.O.- NORMALLY OPEN). On AM-150,
the blocked inlet switch (PS3) contacts
(N.C.-NORMALLY CLOSED) are also checked. If
the(PS1) contacts areOPEN and the(PS3)contacts
(AM-150 only) are “CLOSED”, the GC-4A control
will begin the timed ignition sequence. If either or
bothof the pressure switchcontactsis inanincorrect
position, the GC-4A goes on “HOLD” (Red Light
“ON”; GC-4A Light “ON”) unti switch position is
corrected.
4. With the above condition satisfied, the GC-4A
control will begin a timed pre-purge sequence
(35-seconds); start the fan; and check the fan
Prove Switch (PS2) contact position. This switch
contact (N.O.), must close proving blower operation
before any gas ignition will occur. If the Fan Prove
Switch (PS2) contacts are “CLOSED” after the
initial 35-second pre-purge, the control will continue
with an attempt for gas ignition. If the (PS2)
contacts remain “OPEN” there will be no attempt
for ignition (no spark or gas valve will energize)
but, the fan will continue to run. After an additional
26-seconds, the control will recheck the contacts
on (PS2). If the contacts remain open, again
there will be no attempt for ignition and the fan will
continue to run. The control will check the contact
on switch (PS2) three more times at 26-second
intervals. If the contacts remain open, there will
be no attempt at ignition. After the fifth check of
the contacts, the fan will remain energized for a
30-secondpost-purgeperiod,afterwhichtheignition
sequence will end and the GC-4A light will begin to
blink (Red Light ON) indicating “LOCKOUT”
(temporary). This ignition sequence will have
taken 2 min. 45 seconds. Fifteen minutes later, the
control will automatically begin a second ignition
sequence attempt. If the condition remains
uncorrected the retry sequence above will be
repeated up to 10 times before a 100% system-
lockout occurs. See “AUTOMATIC RESTART
FEATURE” section.
