beautypg.com

Caution – Bryant 313AAV User Manual

Page 39

background image

39

Table 11 – Speed Selection

COLOR

SPEED

AS SHIPPED

Gray

5

COOL

Yellow

4

SPARE

Blue

3

HEAT

Orange

2

SPARE

Red

1*

CONT FAN

* Continuous---blower speed---as shipped default

FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace

life.
Recheck temperature rise. It must be within limits specified

on the rating plate.

Recommended operation is at the

mid--point of rise range or slightly above.

CAUTION

!

6. Set thermostat heat anticipator.

a. Mechanical thermostat -- Set thermostat heat anticipator

to match the amp. draw of the electrical components in
the R--W circuit. Accurate amp. draw readings can be

obtained at the wires normally connected to thermostat
subbase terminals, R and W. The thermostat anticipator

should NOT be in the circuit while measuring current.

(1.) Remove thermostat from subbase or from wall.
(2.) Connect an amp. meter as shown in Fig. 54 across

the R and W subbase terminals or R and W wires at
wall.

(3.) Record amp. draw across terminals when furnace is

in heating and after blower starts.

(4.) Set heat anticipator on thermostat per thermostat

instructions and install on subbase or wall.

b. Electronic thermostat: Set cycle rate for 4 cycles per hr.

7. Adjust blower off delay The blower off delay has 4

adjustable settings from 90 sec to 180 sec. The blower off
delay jumpers are located on the furnace control board.

(See Fig. 24.)

To change the blower off delay setting, move the jumper

from one set of pins on the control to the pins used for the
selected blower off delay. Factory off delay setting is 120

sec.

8. Set airflow CFM for cooling

Select the desired blower motor speed lead for cooling

airflow. See Table 5--Air Delivery--CFM (With Filter). See
Table 11 for lead color identification.

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(es)

This control shuts off combustion control 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 duct system 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.

c. Unblock return air to permit normal circulation.

d. Burners will re--light when furnace cools down.

2. Check draft safeguard switch.

The purpose of this control is to cause the safe shutdown
of the furnace during certain blocked vent conditions.

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

A96316

Fig. 54 -- Amp. Draw Check with Ammeter

a. Verify vent pipe is cool to the touch.

b. Disconnect power to furnace and remove vent connector

from furnace vent elbow.

c. Restore power to furnace and set room thermostat above

room temperature.

d. After normal start--up, allow furnace to operate for 2

minutes, then block vent elbow in furnace 80 percent of
vent area with a piece of flat sheet metal.

e. Furnace should cycle off within 2 minutes. If gas does not

shut off within 2 minutes, determine reason draft

safeguard switch did not function properly and correct
condition.

f. Remove blockage from furnace vent elbow.

g. Switch will auto--reset when it cools.
h. Re--install vent connector.

NOTE: Should switch remain open longer than 3 minutes,
furnace control board will lockout the furnace for 3 hours. To
reset furnace control board, turn thermostat below room
temperature or from HEAT to OFF and turn 115v power OFF,
then back ON.

3. Check Pressure Switch

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

properly and correct condition.

f. Turn off 115--v power to furnace.

g. Reconnect inducer motor wires, replace outer door, and

turn on 115--v power.

h. Blower will run for 90 sec before beginning the call

forheat again.

i. Furnace should ignite normally.

313A