SYSTEM OPERATION
27
Continous Fan
1. When the thermostat calls for continuous fan (G) with
out a call for heat or cooling, the indoor the fan has a
7 second delay on make and energizes the “HEAT”
speed. The fan remains energized as long as the call
for fan remains without a call for heat or cooling. The fan
call “G” has a 60 second delay on break.
Note:
When
the Configuration tab is broken, the continuous fan
mode “G” will have a 7 second delay on make and a 60
second delay on break and the “COOL” speed tap will
be energized.
2.
If a call for cool (Y) occurs during continuous fan, the
blower will switch over to “COOL” speed.
3.
If a call for heat (W) occurs during continuous fan, the
blower will remain energized through the heat cycle or
until “G” is de-energized.
4.
The continuous fan operation will function while the
control is in heat mode lockout.
Cool Mode
1.
When the thermostat calls for cooling (“Y”), the control
energizes the cooling speed fan after a 7 second on
delay. The control provides a 3 minute anti-short cycle
protection for the compressor. If the compressor has
been off for 3 or more minutes, the compressor imme-
diately energizes when the thermostat calls for cool. If
the compressor has not been off for at least 3 minutes
when a call for cool occurs, the control waits until 3
minutes has elapsed from the time the compressor
was last de-energized before re-energizing the com-
pressor.
2.
When the thermostat removes the call for cooling (“Y”)
the compressor is deenergized and the control
deenergizes the cooling speed fan after a cooling off
delay period of 60 seconds.
Note:
A call for cooling has priority over continuous fan. If
G is energized while Y is energized, during the cooling fan
on delay, the fan will remain off until the delay is over.
Note:
The cooling fan operation will continue to function
while the control is in heat lockout.
Note:
If a call for heat exist with a call for cooling, the call
for heat shall proceed as normal except the fan remains
energized on cool speed.
Heat Mode
1.
CALL FOR HEAT - The thermostat calls for heat by
energizing the “W” terminal. The control checks to see
if the end switch is open. If the end switch is closed, the
control will flash code “3” on the LED and wait indefi-
nitely for the end switch to open. The control will
lockout the call for heat if the end switch is closed
before the induced draft motor is energized.
2.
PRE-PURGE - The control energizes the induced draft
motor, flashes code “2” on LED, and waits for the
pressure switch to close. When the pressure switch
has closed, the control stops flashing the LED and
begins timing the 15 second pre-purge period. (
Note:
Under normal operation, the LED will not flash if the
pressure switch closes immediately after energizing
the induced draft motor.)
3.
IGNITION - The control energizes the gas valve and
spark. If flame is not established within 7 seconds, the
gas valve and spark is de-energized and the control
goes to an inter-purge. If flame is established, the
spark is de-energized and the control goes to heat
blower on delay.
4.
Heat Blower On Delay - The control waits for 30 second
heat fan on delay and then energizes the indoor blower
heat speed. If the blower is already energized by a call
for cooling or continuous fan, or in a blower off delay
period, the on delay is skipped and control goes to
steady heat.
5.
STEADY HEAT - Control inputs are continuously
monitored to ensure limit and pressure switches are
closed, flame is established, and the thermostat call
for heat remains.
6.
POST PURGE - When the thermostat demand for heat
is satisfied, the control immediately deenergizes the
gas valve. The inducer output remains on for a 29
second post-purge period.
7.
Heat Blower Off Delay - The indoor blower motor is de-
energized after the selected blower off delay time.
Blower timing begins when the thermostat is satisfied.
A/GPG13
PCBAG123 IGNITION CONTROL SEQUENCE OF OPERATION
3
2
1
6
5
4
9
8
7
12
11
10
L2
L2
L2
L2
COOL
HEAT
UNUSED
L1
L1
D1
FS
D
iag
n
o
st
ic
L
E
D
Blower Off Delay Settings
Transformer
speed up
