Carrier 59MN7B Installation, Start-Up, Operating And Service And Maintenance Instructions page 71

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
Fig. 63 - - Amp. Draw Check with Ammeter
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.
HOOK-AROUND
AMMETER
= 0.5 AMPS FOR THERMOSTAT
ANTICIPATOR SETTING
A96316
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
pressure switch is functioning properly, hot surface igniter
should NOT glow and control diagnostic light flashes a
status code 32 . If hot surface igniter glows when inducer
motor is disconnected, shut down furnace immediately.
e. Determine reason pressure switch did not function proper-
ly and correct condition.
f. Turn off 115- -v power to furnace.
g. Reconnect inducer motor wires, replace blower 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 switches SW1- -1 and SW1- -6 are OFF and other
setup switches are set as desired. Verify that switches
SW1- -7 and SW1- -8 for the blower OFF DELAY are set as
desired per Table 17.
3. Verify that blower and control doors are properly installed.
4. Verify that there are no unsealed openings in the blower
shelf or casing.
5. Cycle test furnace with room thermostat.
6. Check operation of accessories per manufacturer's instruc-
tions.
7. Review Owner's Manual with owner.
8. Attach literature packet to furnace.
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