Adjust Blower Off Delay (Heat Mode); Adjust Cooling Airflow; Adjust Thermostat Heat Anticipator; Check Safety Controls - International comfort products N9MSE0401410A Service And Technical Support Manual

SERVICE AND TECHNICAL SUPPORT MANUAL
Change these settings as required to maintain proper
temperature rise for Heating and Cooling, as described, above.
To change blower motor speed selections for heating mode,
remove blower motor lead from control HEAT terminal. (See
Figure 4) Select desired blower motor speed lead from one of
the other motor leads and relocate it to HEAT terminal.
(Reconnect original lead on SPARE terminal.

Adjust Blower Off Delay (Heat Mode)

The blower off delay has four adjustable settings from 90 sec to
180 sec. (See Table 4) The blower off delay jumpers are
located on the furnace control (See Figure 4) To change the
blower off delay setting, move the jumper from one set of pins
on the control to the pins used for the desired blower off delay.
Factory blower off delay setting is 120 sec.
Table 4 Blower Off Delay Jumper Positions
PINS 1 AND 2
Time (in sec.) 90

Adjust Cooling Airflow

The cooling airflow can be set from the remaining blower speed
taps. Refer to the Air Delivery Tables in these instructions.

Adjust Thermostat Heat Anticipator

When using a non−electronic thermostat, the thermostat heat
anticipator must be set to match the amp draw of the electrical
components in R−W circuit. Accurate amp draw readings can
be obtained at the thermostat subbase terminals R and W.
Figure 5 illustrates the easy method of obtaining actual amp
draw. The amp reading should be taken after blower motor has
started and furnace is heating. Connect ammeter wires as
shown in Figure 5. The thermostat anticipator should not be in
the circuit while measuring current.
subbase, the thermostat must be disconnected from R and W
wires during current measurement.
manufacturer's instructions for adjusting heat anticipator and for
varying heating cycle length. For an electronic thermostat, set
cycle rate for 3 cycles per hour.
Figure 5 Amp. Draw Check with Ammeter
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
R Y W G
10 TURNS
FROM UNIT 24−V
CONTROL TERMINALS
5.0 AMPS ON AMMETER
EXAMPLE:
10 TURNS AROUND JAWS
10
2 AND 3 3 AND 4 4 AND 5
120 150 180
If thermostat has no
See thermostat
HOOK−AROUND
AMMETER
=
A96316
Specifications subject to change without notice.

Check Safety Controls

The flame sensor, gas valve, and pressure switch were all
checked in the Start−up procedure section as part of normal
operation.
1. Check Main Limit Switch
This control shuts off combustion system and energizes
air−circulating blower motor, if furnace overheats. By
using this method to check limit control, it can be
established that limit is functioning properly and will
operate if there is a restricted return−air supply or motor
failure. If limit control does not function during this test,
cause must be determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of
cardboard or sheet metal until the limit trips.
c. Unblock return air to permit normal circulation.
d. Burners will re−light when furnace cools down.
2. Check Pressure Switch(es)
This control proves operation of the draft inducer blower.
a. Turn off 115−v power to furnace.
b. Disconnect inducer motor lead wires from wire
harness.
c. Turn on 115−v power to furnace.
d. Set thermostat to "call for heat" and wait 1 minute.
When low pressure switch is functioning properly, hot
surface igniter should NOT glow and control
diagnostic light flashes a status code 3. If hot surface
igniter glows when inducer motor is disconnected,
shut down furnace immediately.
e. Determine reason low pressure switch did not
function properly and correct condition.
f. Turn off 115−v power to furnace.
g. Reconnect inducer motor wires, replace door, and
turn on 115−v power.
h. Blower will run for 90 seconds before beginning the
call for heat again.
i. Furnace should ignite normally.

Checklist

1. Put away tools and instruments. Clean up debris.
2. Verify that the jumper is removed from the TEST/TWIN
terminal. Verify that there is nothing plugged into the PLT
connector.
NOTE: If there is a jumper connector plugged into PLT, remove
it and discard. (See Figure 4)
3. Verify that the Heat Off Delay jumpers are set as desired.
(See Figure 4)
4. Verify that the blower and control ("Main") doors are
properly installed.
5. Verify that the Status LED glows. If not, check that the
power supply is energized and that the blower door is
secure. (See Figure 14) to interpret diagnostic codes
6. Cycle test furnace with room thermostat to be sure that it
operates properly with the room thermostat. Check all
modes including Heat, Cool and Fan.
7. Check operation of accessories per manufacturer's
instructions.
8. Review Home Owner's Information with owner.
9. Attach entire literature packet to furnace.
Gas Furnace: N9MSE
.
440 04 4401 00