The preferred method of checking the limit control is to
gradually block off the return air after the furnace has been
operating for a period of at least 5 minutes. As soon as the
limit has shut off the burners, the return-air opening should
be unblocked. By using this method to check the limit
control, it can be established that the limit functions and
operates properly if there is a motor failure.
2. Check blocked vent safeguard switch.
The purpose of this control is to cause the safe shutdown of
the furnace during certain blocked vent conditions.
a. Disconnect power to furnace and remove vent connector
from furnace flue collar. 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 flue outlet 100 percent. Furnace
should cycle off within 2 minutes.
d. Remove blockage and reconnect vent pipe to furnace
outlet collar.
e. Wait 5 minutes and then reset blocked vent safeguard
switch.
3. 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 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 31. 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 control door, and
turn on 115-v power.
F.
Checklist
1. Put away tools, instruments, and clean up debris.
2. Verify manual reset switches have continuity.
3. Ensure blower and control access doors are properly in-
stalled.
4. Cycle test 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.
→
Fig. 12—Redundant Automatic White Rodgers
Gas Control Valve
A00238
Fig. 13—Burner Flame
A89020
;;
;;
BURNER FLAME
BURNER
MANIFOLD
TABLE 9—SPEED SELECTOR
COLOR
SPEED
FACTORY-
ATTACHED TO
Black
High
Cool
Yellow (When
present)
Medium-High
Spare
Blue
Medium-Low
Heat
Red
Low
Spare
White
Common
L2/COM
Fig. 14—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
—17—
Содержание GAS-FIRED INDUCED-COMBUSTION FURNACES 383KAV
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