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 outlet collar. Be sure to allow time for vent
pipe to cool down before removing.
b. Set room thermostat above room temperature and restore
power to furnace.
c. After normal startup, allow furnace to operate for 2
minutes, then block flue outlet (50 percent). Furnace
should cycle off within 3 minutes.
d. Remove blockage and reconnect vent pipe to furnace
outlet collar.
e. Wait 5 minutes and then reset draft safeguard switch.
4. Check pressure switch.
This control proves operation of draft inducer blower.
a. Turn off 115-v power to furnace.
b. Remove control door and disconnect inducer motor lead
wires from wire harness.
c. Turn on 115-v power to furnace.
d. Close thermostat switch as if making normal furnace
start. If the burners do not light, the pressure switch is
functioning properly.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace control door, and
turn on 115-v power.
5. Check auxiliary limits.
a. Turn off 115-v power to furnace.
b. Remove blower access door.
c. Disconnect red motor lead at blower speed selector.
Mark terminal for proper reconnection.
d. Replace blower access door.
e. Turn on 115-v power to furnace. Be sure room thermo-
stat is "calling for heat".
f. Allow furnace to operate until auxiliary limit activates,
but DO NOT operate furnace longer than 4 minutes.
g. If furnace operates for 4 minutes, check/replace auxiliary
limit switch.
h. Turn off 115-v power to furnace.
i. Remove blower access door.
j. Reconnect red motor lead and replace door.
k. Turn on 115-v power to furnace.
F.
Checklist
1. Put away tools and instruments, and clean up debris.
2. Verify manual reset switches have continuity.
3. Ensure blower and control access doors are properly in-
stalled.
4. Cycletest furnace with room thermostat.
5. Check operation of accessories per manufacturer’s instruc-
tions.
6. Review User’s Manual with owner.
7. Leave literature packet near furnace.
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