24
5. When the thermostat is satisfied, the
G
,
O
and
Y
terminals on the control board are de-energized
opening the compressor contactor, and de-energizing
the reversing valve.
6. The circulating air blower will operate at 1/2 of the
selected speed for 60 seconds, and de-energize.
Fan Mode
1. On a call for fan operation, the thermostat applies 24
VAC to the
G
terminal on the furnace control board.
2. The circulating air blower ramps to 1/2 of the selected
airflow.
EQUIPMENT MAINTENANCE
WARNING:
To avoid risk of electrical shock, personal injury,
or death, disconnect all electrical power to the unit
before performing any maintenance or service.
The unit may have more than one electrical supply.
Label all wires prior to disconnection when
servicing the unit. Wiring errors can cause
improper and dangerous operation
CAUTION:
Use care when removing parts from this unit.
Personal injury can result from sharp metal
edges present in all equipment of sheet metal
construction.
Proper maintenance is important to achieve optimum
performance from the heat pump. The ability to properly
perform maintenance on this equipment requires certain
mechanical skills and tools. If you do not possess these
skills, contact your dealer for maintenance. Consult your
local dealer about the availability of maintenance contracts.
Routine maintenance should include the following:
CAUTION:
The unit should never be operated without a
filter in the return air system. Replace disposable
filters with the same type and size.
• Inspect and clean or replace air filters at the beginning
of each heating and cooling season, or more frequently
if required.
• Inspect the condensate drain and outdoor coil at the
beginning of each cooling season. Remove any debris.
Clean the outdoor coil and louvers as necessary using
a mild detergent and water. Rinse thoroughly with water.
• Inspect the electrical connections for tightness at the
beginning of each heating and cooling season. Service
as necessary.
• The blower compartment should be cleaned monthly
during the heating and cooling seasons to remove
After Initial Power up:
The control has a programmed
adaptive ignition feature which varies the warm-up
period as follows: If ignition is successful the warm-up
is
reduced
by 3-seconds on each subsequent call for
heat until ignition failure occurs. Upon ignition failure,
the warm-up is
increased
by 3-seconds on the next try.
If successful, the timing remains fixed at this level. In
general, whenever ignition failure occurs the warm-up
interval is increased by 3-seconds on the next try. And
if successful, it remains there. Minimum and maximum
warm-up time limits are set at 6 and 54 seconds.
7. The furnace control must prove flame via the flame
sensor 5 seconds after the gas valves open. If flame
is sensed, burners are on and the igniter cools off. If
no flame is sensed, the gas valve closes immediately
and the inducer continues to run. A second trial for
ignition (step 6) begins. If no flame is sensed on the
fifth try for ignition, the furnace control is locked and the
red LED will blink 4 times repetitively. The thermostat
must be opened for at least ten seconds to reset the
furnace control after a lock out. Otherwise, the furnace
will attempt another ignition sequence in 1 hour.
8. The furnace control energizes the circulating air blower
at a very low speed. After 30 seconds, the blower will
ramp to the airflow selected for heating.
9. If the unit is wired for two stage operation, only the
low-fire burners will fire. If the need for stage 2 occurs,
the gas valve will open further, firing the remaining
burners. At this time the circulating air blower will ramp
up to the high-fire airflow.
10. When the thermostat has been satisfied, gas valve is
de-energized.
11. The inducer is de-energized after a 30 second
postpurge.
12. The circulating air blower remains on for 120 seconds.
13. Abnormal conditions: If a limit opens during operation,
the inducer blower continues to operate. The gas
valve is de-energized immediately. The inducer blower
continues to operate until the limit closes, then is de-
energized.
2-Stage Cooling Mode
1. On a call for cooling the thermostat closes, applying
24 VAC to the
G
,
O
and
Y1
terminals on the control.
This closes the compressor contactor, energizes the
reversing valve, and the compressor operates on 1st
stage.
2. The control energizes the circulating blower to 1/3 of
the selected airflow for approximately 30 seconds.
3. The circulating blower will then ramp to approximately
3/4 of the selected airflow for another 30 seconds before
adjusting to full airflow until the thermostat is satisfied.
4. If the thermostat is not satisfied in the required time,
based on the operation of the two-stage cooling
thermostat,
Y2
will energize and the compressor will
run at second stage. Refer to the thermostat installation
instructions for the cooling profile.
