Caution, Service, 312a – Bryant 2-stage Deluxe Induced-Combustion 4-way Multipurpose 120 User Manual

Page 47

Advertising
background image

47

CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care

and wear appropriate protective clothing, safety glasses and

gloves when handling parts and servicing furnaces.

CAUTION

!

The minimum maintenance on this furnace is as follows:

1. Check and clean air filter each month or more frequently if

required. Replace if torn.

2. Check blower motor and wheel for cleanliness each

heating and cooling season. Clean as necessary.

3. Check electrical connections for tightness and controls for

proper operation each heating season. Service as

necessary.

4. Inspect burner compartment before each heating season

for rust, corrosion, soot or excessive dust. If necessary,

have furnace and burner serviced by a qualified service
agency.

5. Inspect the vent pipe/vent system before each heating

season for rust, corrosion, water leakage, sagging pipes or
broken fittings. Have vent pipes/vent system serviced by a

qualified service agency.

6. Inspect any accessories attached to the furnace such as a

humidifier or electronic air cleaner. Perform any service or
maintenance to the accessories as recommended in the
accessory instructions.

CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2.
CONTINUOUS ON - Control has 24VAC power.
RAPID FLASHING - Line voltage (115VAC) polarity reversed. If twinned, refer to twinning kit instructions.

LED CODE

EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY THE NUMBER OF LONG FLASHES.

STATUS

11 NO PREVIOUS CODE - Stored status code is erased automatically after 72 hours.

On RED LED boards stored status codes can also be erased when power
(115 VAC or 24 VAC) to control is interrupted.

12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC) -Blower runs for the

selected blower off-delay time, if unit is powered up during a call for heat
(R-W/W1 closed) or (R-W/W1) opens during blower on-delay.

13 LIMIT CIRCUIT LOCKOUT - Lockout occurs if a limit, draft safeguard, flame rollout,

or blocked vent switch (if used) is open longer than 3 minutes.

- Control will auto reset after three hours. - Refer to #33.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto reset.

Check for: - Mis-wired gas valve

- Defective control (valve relay)

22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is de-

energized. Inducer will run until fault is cleared. Check for:
- Leaky gas valve - Stuck-open gas valve

23 PRESSURE SWITCH DID NOT OPEN Check for: - Obstructed pressure tubing

- Pressure switch stuck closed

24 SECONDARY VOLTAGE FUSE IS OPEN Check for: - Short circuit in secondary

voltage (24VAC) wiring.

31 HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED

Control relay may be defective, refer to status code #32

If status code recall is needed, briefly remove then reconnect one main limit wire to display last stored status code. On RED LED boards do not remove power or blower door before initiating status code recall.

COMPONENT TEST

327598-101 REV. C

SERVICE

32

LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED - If open longer than
five minutes, inducer shuts off for 15 minutes before retry. If opens during blower on-delay
period, blower will come on for the selected blower off-delay. Check for:
- Excessive wind

- Restricted vent

- Defective inducer motor

- Proper vent sizing

- Defective pressure switch - Low inducer voltage (115 VAC)

- Inadequate combustion air supply - Low inlet gas pressure (if LGPS used)
- Disconnected or obstructed pressure tubing

33 LIMIT CIRCUIT FAULT - Indicates a limit, draft safeguard, flame rollout, or blocked vent

switch (if used) is open. Blower will run for 4 minutes or until open switch remakes
whichever is longer. If open longer than 3 minutes, code changes to lockout #13. If open
less than 3 minutes status code #33 continues to flash until blower shuts off. Flame rollout
switch and BVSS require manual reset. Check for: - Dirty filter or restricted duct system

- Defective blower motor or capacitor - Proper vent sizing

- Restricted vent

- Defective switch or connections - Loose blower wheel

- Excessive wind

- Inadequate combustion air supply (Flame Roll-out Switch open).

34 IGNITION PROVING FAILURE - Control will try three more times before lockout #14 occurs.

If flame signal lost during blower on-delay period, blower will come on for the selected
blower off-delay. Check for: - Oxide buildup on flame sensor (clean with fine steel wool)
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal)
- Manual valve shut-off

- Control ground continuity

- Gas valve defective or gas valve turned off - Low inlet gas pressure
- Inadequate flame carryover or rough ignition - Defective Hot Surface Ignitor
- Flame sensor must not be grounded
- Green/Yellow wire MUST be connected to furnace sheet metal

43 LOW-HEAT PRESSURE SWITCH OPEN WHILE HIGH-HEAT PRESSURE SWITCH IS

CLOSED - Check for:

- Disconnected or obstructed pressure tubing

- Mis-wired pressure switches

- Low-heat pressure switch stuck open

- Low inlet gas pressure (if LGPS used)

45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;

- Gas valve relay stuck open - Flame sense circuit failure

- Software check error

Reset power to clear lockout. Replace control if status code repeats.

To initiate the component test sequence, shut OFF the room thermostat or disconnect the
"R" thermostat lead. Briefly short the TEST/TWIN terminal to the "Com 24V" terminal.
Status LED will flash last status code and then turn ON the inducer motor. The inducer
motor will start in HIGH speed and remain on HIGH speed until the end of the test then
shift to LOW speed for 7 to 15 seconds. The hot surface igniter, blower motor LO HEAT
speed, blower motor HI HEAT speed, and blower motor COOL speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on. When the blower is
turned OFF the inducer will be switched to low-speed for 10 seconds.

A04210

Fig. 57 -- Service Label

312A

Advertising