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Control initiates a 90-sec blower only on period before starting
another heat pump cycle if there is a power interruption. Anytime
control senses false flame, control locks out of heating mode. This
reaction occurs because control ignores W input due to false flame
signal and, as a result, sees only Y input and goes into cooling
mode blower off delay. All other control functions remain in
standard format.
NOTE: EAC-1 terminal is energized whenever blower operates.
HUM terminal is only energized when gas valve is energized.
V. COMPONENT TEST
NOTE: The furnace control component test allows all compo-
nents to run for a short time; except the gas valve and humidifier
terminal HUM are not energized for safety reasons. The EAC-1
terminal is energized when the blower is energized. This feature
helps diagnose a system problem in case of a component failure.
The component test feature will not operate if any thermostat
signal is present ant the control and not until all time delays are
completed.
NOTE: Record the status code BEFORE opening the blower
access door and before shutting off power to the furnace. Opening
the blower access door will open the blower door switch and shut
off power within the furnace. When power to the furnace is shut
off by either method, the status code will be lost because the code
is not stored while power is removed for any reason.
To Begin Component Self-Test:
WARNING: Blower access panel door switch opens
115-v power to control center. No component operation
can occur. Caution must be taken when manually closing
this switch for service purposes. Failure to follow this
warning could result in electrical shock, personal injury,
or death.
1. Remove blower access door.
2. Disconnect the thermostat R lead from furnace control.
3. Manually close blower door switch.
4. For approximately 2 sec, short (jumper) the C
OM-24v
terminal on control to the TEST/TWIN 3/16-inch quick-
connect terminal on control until the LED goes out.
Remover jumper from terminals. (See Fig. 31.)
NOTE: If TEST/TWIN and C
OM-24v terminals are jumpered
longer than 2 sec, LED will flash rapidly and ignore component
test request.
Component test sequence is as follows:
a. LED will display previous status code 4 times.
b. Inducer motor starts and continues to run until Step f of
component test sequence.
c. After 7 seconds the hot surface igniter is energized for 15
sec, then off.
d. Blower motor operates on HEAT speed for 10 sec.
e. Blower motor operates on COOL speed for 10 sec.
f. Inducer motor stops.
5. Reconnect R lead to furnace control, remove tape from
blower door switch, and re-install blower door.
6. Operate furnace per instruction on outer door.
7. Verify furnace shut down by lowering thermostat setting
below room temperature.
8. Verify that furnace restarts by raising thermostat setting
above room temperature.
START-UP PROCEDURES
I. GENERAL
1. Furnace must have a 115-v power supply properly con-
nected and grounded. Proper polarity must be maintained
for correct operation.
NOTE: Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, control center LED status light will flash
rapidly and furnace will not operate.
2. Thermostat wire connections at terminals R, W, G, and Y
must be made at 24-v terminal block on furnace control.
3. Natural gas service pressure must not exceed 0.5 psig
(14-in. wc), but must be no less than 0.16 psig (4.5-in. wc).
4. Blower access panel must be in place to complete 115-v
electrical circuit to furnace.
CAUTION: These furnaces are equipped with a manual
reset limit switch in burner box. This switch will open
and shut off power to gas control if an overheat condition
(flame rollout) occurs in burner enclosure. Correct inad-
equate combustion-air supply or improper venting condi-
tion and reset switch. DO NOT jumper this switch.
Failure to follow this caution will result in intermittent
unit operation or performance satisfaction.
Before operating furnace, check flame rollout manual reset switch
for continuity. If necessary, press button to reset switch.
II. PRIME CONDENSATE TRAP WITH WATER
CAUTION: Condensate trap must be PRIMED or
proper draining may not occur. The condensate trap has 2
internal chambers which can ONLY be primed by pour-
ing water into the inducer drain side of condensate trap.
Failure to follow this caution will result in intermittent
unit operation or performance satisfaction.
1. Remove upper inducer housing drain connection cap. (See
Fig. 48)
2. Connect field-supplied 1/2-in. ID tube to upper inducer
housing drain connection.
3. Insert field-supplied funnel into tube.
4. Pour 1 quart of water into funnel/tube. Water should run
through inducer housing, overfill condensate trap, and flow
into open field drain. (See Fig. 49.)
5. Remove funnel and tube from inducer housing and replace
drain connection cap and clamp.
III. PURGE GAS LINES
WARNING: Never purge a gas line into a combustion
chamber. Never test for gas leaks with an open flame. Use
a commercially available soap solution made specifically
for the detection of leaks to check all connections. Failure
to follow this warning could result in fire, explosion,
personal injury, or death.
If not previously done, purge lines after all connections have been
made and check for leaks.
IV. ADJUSTMENTS
A. Set Gas Input Rate
Furnace gas input rate on rating plate is for installations at altitudes
up to 2000 ft.
In the U.S.A., the input ratings for altitudes above 2000 ft must be
reduced by 2 percent for each 1000 ft above sea level.
In Canada, the input ratings must be derated by 5 percent for
altitudes of 2000 ft to 4500 ft above sea level.
Furnace input rate must be within ±2 percent of input on furnace
rating plate adjusted for altitude.
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