Bryant 312AAV - Manual (Page 28)

2. Check draft safeguard switch.
The purpose of this control is to permit the safe shutdown of the
furnace during certain blocked vent conditions.
a. Disconnect power to furnace and remove vent connector
from furnace vent elbow. Be sure to allow time for vent
pipe to cool down before removing.
b. Restore power to furnace and set room thermostat above
room temperature.
c. After normal start-up, allow furnace to operate for 2
minutes, then block vent elbow in furnace 100 percent.
Furnace should cycle off within 2 minutes.
d. Remove blockage and reconnect vent pipe to furnace
vent elbow.
e. Switch will auto-reset when it cools.
3. Check Pressure Switch
This control proves operation of the draft inducer blower.
a. Turn off 115-v power to furnace.
b. Remove outer door and 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. Determine reason pressure switch did not
function properly and correct condition.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace outer door, and
turn on 115-v power.
VI. CHECKLIST
1. Put away tools and instruments. Clean up debris.
2. Check that switches for LHT and OFF-DLY are selected as
desired.
3. Verify that blower and burner access doors are properly
installed.
4. Cycle test furnace with room thermostat.
5. Check operation of accessories per manufacturer’s instruc-
tions.
6. Review User’s Guide with owner.
7. Leave literature packet near furnace.
Fig. 35–Amp Draw Check With Ammeter
A96316
R Y W G
10 TURNS
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)
HOOK-AROUND
AMMETER
EXAMPLE: 5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS
= 0.5 AMPS FOR THERMOSTAT
ANTICIPATOR SETTING
FROM UNIT 24-V
CONTROL TERMINALS
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