Goodman GRL SERIES Installation Instructions Manual page 41

f. If flame is established and
maintained during the trial for
ignition period and flame is lost,
the gas valve is de-energized, the
draft inducer stops after a 10-
second post-purge. The blower
motor runs at the high-fire or low-
fire heating speed (depending on
state when flame was lost) until it
completes the blower-off delay.
When the blower-off delay is over,
the control initiates another ignition
trial period by starting the inducer
for the pre-purge. The control will
recycle up to 5 flame losses (4 re-
cycles) within a single call for heat
before going into lockout.
TO SHUT DOWN FURNACE
1. Set the room thermostat to its
lowest setting.
2. Shut off the gas to main burners
by setting the gas control switch to
the "OFF" position, or by turning
the manual gas stop closed.
Sequence of operation with two
stage thermostat
Connect W1 on thermostat to W on
IFC. Connect W2 on thermostat to
W2 on IFC.
Call for 1st stage heat
a. R and W thermostat contacts close
and the IFC runs a self check
routine. After the IFC verifies that
both sets of pressure switch
contacts are open, the induced
draft motor starts on high until both
pressure switch contacts close (a
maximum of 60 seconds).
b. After a 30 second pre-purge the
spark igniter energizes and the gas
valve (high stage) opens, lighting
the burners.
c. After the burners light, the remote
flame sensor must prove ignition. If
the burners do not light or flame
cannot be proven, the system goes
through another ignition sequence.
It does this up to 4 times.
d. Twenty seconds after flame sense,
the main blower energizes on low
speed, the gas valve drops to low
fire, and the inducer drops to low
speed. The furnace continues to
run on low until the call for heat is
satisfied or the second-stage
contacts close. If the first-stage call
for heat is satisfied the gas valve
de-energizes and the induced draft
motor continues running for a 10
second post purge time. The main
blower runs for the user-defined
blower-off delay (this timing is field
adjustable). See Figure 35 for
switch settings.
Call for 2nd stage heat after 1st
stage
R and W2 thermostat contacts close,
calling for 2-stage heat. The induced
draft motor then switches to high
speed and the high pressure switch
contacts will close. The gas valve
switches to high fire and the main
blower switches to high-fire heating
speed.
2nd stage heat satisfied, 1st stage
heat still required.
R and W2 thermostat contacts open
(W1 to R remains closed). The
induced draft motor switches to low
speed, the main blower motor
switches to low-fire heating speed
and the gas valve changes to low.
The furnace continues to run in this
mode until the first-stage heat call is
satisfied. The system will shut down
as noted in "d," under first-stage call
for heat.
Call for second-stage heat with no
other existing heat call present.
a-c. Same operation as call for first-
stage heat
d. Main blower starts on high
speed 20 seconds after gas
valve energizes. The furnace
continues to run on high until
the W2 contacts open. If W2 and
W1 open at the same time (both
high & low stages are satisfied),
the gas valve de-energizes and
the inducer continues to run for a
10-second post-purge. The main
blower runs for the user selected
blower-off delay. See Figure 36
for switch settings.
NOTE: Under certain conditions the
furnace may alternate between low
and high fire continuously. This
operation is based on demand from
the thermostat and is controlled by
the thermostat. This operation is
normal and can be expected at times
to maintain optimum comfort.
SETTING BLOWER TIMING
The UT ELECTRONIC CONTROLS
IFC has four quick connect terminals
for connecting the motor speed leads.
These are:
1. FAN SPEED/LOW — motor runs
on this speed when the
thermostat is in the "FAN ON"
position or when in low-fire
heating speed heat.
2. COOL — connect desired
cooling speed.
3. HEAT — connect desired high-
fire heating speed.
4. HEAT/COOL — connect desired
speed when high heating and
cooling speed are the same.
High fire and low fire blower timing
are the same.
IMPORTANT: Do not connect any
motor speeds to "HEAT" and "COOL"
if you use the "HEAT/COOL" terminal.
FIGURE 35
UT ELECTRONIC CONTROLS 1095-102 &
1095-104 BLOWER OFF TIMING
NOTE: Switch number 4 must be in
"OFF" position for all applications.
SW1 SW2 HEAT
OFF OFF 90
OFF ON 150
ON OFF 120
ON ON 180
COOL
40
30
60
90
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