International comfort products A Series Installation Instructions Manual page 49

NOTE: If the temperature rise is outside this range, first check:
(3.) Gas input for heating operation.
(4.) Return and supply ducts for excessive restrictions
causing static pressures greater than the maximum
heating static listed on the rating plate.
c. Adjust air temperature rise by adjusting blower speed. In-
crease blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise
d. Turn thermostat down below room temperature and re-
move blower access door.
e. To change motor speed selection for heating, remove
blower motor lead from control HEAT terminal - - Wiring
Diagram (Fig. 68) Select desired blower motor speed lead
from one of the other terminals and relocate it to the HEAT
terminal - - lead color identification (Table 11). Reconnect
original lead to SPARE terminal.
f. Repeat steps a through e.
8. Set thermostat heat anticipator.
a. Mechanical thermostat - - Set thermostat heat anticipator to
match the amp. draw of the electrical components in the
R- -W circuit. Accurate amp. draw readings can be obtained
at the wires normally connected to thermostat subbase ter-
minals, R and W. The thermostat anticipator should NOT
be in the circuit while measuring current.
Fig. 61 - - Orifice Hole
WARNING
!
FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve outlet pressure tap must be tightened to prevent
gas leak.
CAUTION
!
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace
life.
Recheck temperature rise. It must be within limits specified
on the rating plate. Recommended operation is at the
mid- -point of rise range or slightly above.
(1.) Remove thermostat from subbase or from wall.
(2.) Connect an amp. meter (Fig. 62) across the R and W
subbase terminals or R and W wires at wall.
440 01 4601 01
EXAMPLE:
b. Electronic thermostat: Set cycle rate for 4 cycles per hr.
9. Adjust Cooling Airflow. The cooling airflow can be set
from the remaining blower speed taps. Refer to the Air
Delivery Tables in these instructions.
10. Adjust blower off delay. The blower off delay has four (4)
adjustable settings from 90 seconds to 180 seconds. The
blower off delay jumpers are located on the furnace control
board - - see wiring diagram (Fig. 68). Position A- -90
seconds, B- -120 seconds, C- -150 seconds, D- -180 seconds.
To change the blower off delay setting, move the jumper
from one set of pins on the control to the pins used for the
selected blower off delay. Factory off delay setting is 120
seconds.
11. Cooling On Delay is fixed at 2 seconds for either jumper
A180238
selection.
Check Safety Controls
1. Check Main Limit Switch(es)
This control shuts off combustion control system and ener-
gizes air- -circulating blower motor, if furnace overheats. By
using this method to check limit control, it can be estab-
lished that limit is functioning properly and will operate if
there is a restricted duct system or motor failure. If limit
control does not function during this test, cause must be de-
termined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of cardboard or
c. Unblock return air to permit normal circulation.
d. Main limit circuit open causes 3 hour lock out.
e. Burners will re- -light when furnace cools down.
Checklist
1. Put away tools and instruments. Clean up debris.
2. Verify that the Blower/Heat Off Delay jumpers are set as
desired. (Fig. 41 and Fig. 68).
3. Verify that there are no unsealed openings in the blower
shelf or casing.
4. Verify that the blower (lower door in upflow position) and
control ("Main" or upper door in upflow position) doors are
properly installed.
Specifications subject to change without notice.
(3.) Record amp. draw across terminals when furnace is
in heating and after blower starts.
(4.) Set heat anticipator on thermostat per thermostat in-
structions and install on subbase or wall.
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
HOOK-AROUND
AMMETER
R Y W G
10 TURNS
FROM UNIT 24-V
CONTROL TERMINALS
0.5 AMPS FOR THERMOSTAT
5.0 AMPS ON AMMETER
=
ANTICIPATOR SETTING
10 TURNS AROUND JAWS
Fig. 62 - - Amp. Draw Check With Ammeter
sheet metal until the limit trips.
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