Bryant GAMA 331JAV - Manual (Page 20)

17. The thermostat anticipator should NOT be in this
circuit while measuring current. If thermostat has no
subbase, thermostat MUST be disconnected from R and
W/W1 wires during current measurement. Return SW-2
to final desired location after completing reading. See
thermostat manufacturer’s instructions for adjusting heat
anticipator and for varying heating cycle length.
b. When using an electronic thermostat, set cycle rate for 3
cycles per hr.
E. Check Safety Controls
The flame sensor, gas valve, and pressure switches were all
checked in the Start-Up section as part of normal operation.
1. Check primary limit control.
This control shuts off combustion control system and
energizes circulating-air blower motor if furnace overheats.
The preferred method of checking limit control is to
gradually block off return air after furnace has been
operating for a period of at least 5 minutes. As soon as limit
has shut off burners, return-air opening should be un-
blocked. By using this method to check limit control, it can
be established that the limit is functioning properly and will
operate if there is a motor failure.
2. Check draft safeguard switch.
The purpose of this control is to permit safe shutdown of he
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
connector 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 connector to
furnace flue collar.
e. Wait 5 minutes and then reset draft safeguard switch.
3. Check flow-sensing pressure switches.
This control proves operation of draft inducer blower.
a. Turn off 115-v power to furnace.
b. Remove gas 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 hot surface ignitor does not glow within several
minutes and control flashes code 32, pressure switches
are functioning properly.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace gas control door,
and turn on 115-v power to furnace.
4. 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 low 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 limit
switch(es).
h. Turn off 115-v power to furnace.
i. Remove blower access door.
j. Reconnect red motor lead, reset switch, and replace door.
k. Turn on 115-v power to furnace.
F. Checklist
1. Put away tools and instruments, and clean up debris.
2. Check SW-1 through SW-4 after completing installation to
ensure desired settings for thermostat type (SW-1 and
SW-2) and blower off delay (SW-3 and SW-4). Refer to
Tables 6 and 7.
3. Verify manual reset switches have continuity.
4. Ensure blower and gas control access doors are properly
installed.
5. Cycle test furnace with room thermostat.
6. Check operation of accessories per manufacturer’s instruc-
tions.
7. Review User’s Manual with owner.
8. Leave literature packet near furnace.
TABLE 11—SPEED SELECTION
COLOR SPEED AS SHIPPED‡
White Common C
OM
Black High Cool
Orange† Med SPARE or Capped
Yellow Med-High SPARE
Blue Med-Low High-Gas-Heat
Red Low* Low-Gas-Heat
* Continuous fan speed.
† Available on 5-speed blowers only.
‡ Terminal on control center.
CAUTION: Recheck temperature rise. It must be within
limits specified on unit rating plate. Recommended op-
eration is at midpoint of rise range or above.
Fig. 17—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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