Haier GE APPLIANCES NF96US Service Manual page 10

RED LED
RECALL BUTTON
Figure 3. Integrated Control
(Automatic Hot Surface Ignition System)
Electronic Ignition
On a call for heat the integrated control monitors the
combustion air inducer pressure switch. The control board
will not begin the heating cycle if the pressure switch is
closed (by-passed). Once the pressure switch is determined
to be open, the combustion air inducer is energized. When
the differential in the pressure switch is great enough, the
pressure switch closes and a 15-second pre-purge begins.
If the pressure switch is not proven within 2-1/2 minutes,
the integrated control goes into Watchguard-Pressure
Switch mode for a 5-minute re-set period.
After the 15-second pre-purge period, the ignitor warms
up for 20 seconds during which the gas valve opens at
19 seconds for a 4-second trial for ignition. The ignitor
remains energized for the first 3 seconds during the 4
second trial. If ignition is not proved during the 4-second
period, the integrated control will try four more times with
an inter purge and warm-up time between trials of 35
seconds. After a total of five trials for ignition (including the
initial trial), the integrated control goes into Watchguard-
Flame Failure mode. After a 60-minute reset period, the
integrated control will begin the ignition sequence again.
Fan Time Control
Heating Fan On Time
The fan on time of 30 seconds is not adjustable.
BLOWER OFF DELAY
Page 10
Heating Fan Off Time
Fan off time (time that the blower operates after the heat
demand has been satisfied) can be adjusted by moving
the jumper to a different setting. The unit is shipped with
a factory fan off setting of 90 seconds. For customized
comfort, monitor the supply air temperature once the heat
demand is satisfied. Note the supply air temperature at the
instant the blower is de-energized.
Adjust the fan-off delay to achieve a supply air temperature
between 90° - 110° at the instant the blower is de-energized.
(Longer delay times allow for lower air temperature, shorter
delay times allow for higher air temperature). See Figure 4.
Cooling Fan On Time
The fan on time is 2 seconds and is not adjustable.
Cooling Fan Off Time
The control has a 45 second fan off delay after cooling
demand has been met. This delay is factory set and not
adjustable.
JUMPER POSITION
PIN1 PIN2
PIN2 PIN3
PIN3 PIN4
PIN4 PIN5
NO JUMPER
To adjust fan-off timing, reposition jumper across pins to
achieve desired setting.
60 Second 90 Second
off time off time
Figure 4. Heat Fan-Off Time in Seconds
Heating Components
Combustion air inducer (B6), primary limit control (S10),
ignitor, burners, flame rollout switch (S47), gas valve
(GV1), combustion air pressure switch (S18), and heat
exchangers are located in the heating compartment. The
heating compartment can be accessed by removing the
outer access panel.
Ignitor (Figure 5)
NF96US units use a nitride ignitor made from a proprietary
ceramic material. To check ignitor, measure its resistance
and voltage. A value of 39 to 70 ohms indicates a good
ignitor. Voltage to the ignitor should be 102 - 132VAC. See
Figure 9 for resistance and voltage checks.
HEAT OFF DELAY
60
90
120
180
180
120 Second 180 Second
off time off time
31-5000728 Rev. 0