Bryant 340MAV Component Test, II. Prime Condensate Trap with Water, III. Purge GAS Lines

Control initiates a 90-sec blower only on period before starting another heat pump cycle if there is a power interruption. Anytime control senses false flame, control locks out of heating mode. This reaction occurs because control ignores W input due to false flame signal and, as a result, sees only Y input and goes into cooling mode blower off delay. All other control functions remain in standard format.

NOTE: EAC-1 terminal is energized whenever blower operates. HUM terminal is only energized when gas valve is energized.

V. COMPONENT TEST

NOTE: The furnace control component test allows all compo- nents to run for a short time; except the gas valve and humidifier terminal HUM are not energized for safety reasons. The EAC-1 terminal is energized when the blower is energized. This feature helps diagnose a system problem in case of a component failure. The component test feature will not operate if any thermostat signal is present ant the control and not until all time delays are completed.

NOTE: Record the status code BEFORE opening the blower access door and before shutting off power to the furnace. Opening the blower access door will open the blower door switch and shut off power within the furnace. When power to the furnace is shut off by either method, the status code will be lost because the code is not stored while power is removed for any reason.

To Begin Component Self-Test:

WARNING: Blower access panel door switch opens 115-v power to control center. No component operation can occur. Caution must be taken when manually closing this switch for service purposes. Failure to follow this warning could result in electrical shock, personal injury, or death.

1.Remove blower access door.

2.Disconnect the thermostat R lead from furnace control.

3.Manually close blower door switch.

4.For approximately 2 sec, short (jumper) the COM-24v terminal on control to the TEST/TWIN 3/16-inch quick- connect terminal on control until the LED goes out. Remover jumper from terminals. (See Fig. 31.)

NOTE: If TEST/TWIN and COM-24v terminals are jumpered longer than 2 sec, LED will flash rapidly and ignore component test request.

Component test sequence is as follows:

a.LED will display previous status code 4 times.

b.Inducer motor starts and continues to run until Step f of component test sequence.

c.After 7 seconds the hot surface igniter is energized for 15 sec, then off.

d.Blower motor operates on HEAT speed for 10 sec.

e.Blower motor operates on COOL speed for 10 sec.

NOTE: Proper polarity must be maintained for 115-v wiring. If polarity is incorrect, control center LED status light will flash rapidly and furnace will not operate.

2.Thermostat wire connections at terminals R, W, G, and Y must be made at 24-v terminal block on furnace control.

3.Natural gas service pressure must not exceed 0.5 psig (14-in. wc), but must be no less than 0.16 psig (4.5-in. wc).

4.Blower access panel must be in place to complete 115-v electrical circuit to furnace.

→CAUTION: These furnaces are equipped with a manual reset limit switch in burner box. This switch will open

and shut off power to gas control if an overheat condition (flame rollout) occurs in burner enclosure. Correct inad- equate combustion-air supply or improper venting condi- tion and reset switch. DO NOT jumper this switch. Failure to follow this caution will result in intermittent unit operation or performance satisfaction.

Before operating furnace, check flame rollout manual reset switch for continuity. If necessary, press button to reset switch.

II.PRIME CONDENSATE TRAP WITH WATER

→CAUTION: Condensate trap must be PRIMED or proper draining may not occur. The condensate trap has 2

internal chambers which can ONLY be primed by pour- ing water into the inducer drain side of condensate trap. Failure to follow this caution will result in intermittent unit operation or performance satisfaction.

1.Remove upper inducer housing drain connection cap. (See Fig. 48)

2.Connect field-supplied 1/2-in. ID tube to upper inducer housing drain connection.

3.Insert field-supplied funnel into tube.

4.Pour 1 quart of water into funnel/tube. Water should run through inducer housing, overfill condensate trap, and flow into open field drain. (See Fig. 49.)

5.Remove funnel and tube from inducer housing and replace drain connection cap and clamp.

III.PURGE GAS LINES

WARNING: Never purge a gas line into a combustion chamber. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections. Failure to follow this warning could result in fire, explosion, personal injury, or death.

f. Inducer motor stops.

5.Reconnect R lead to furnace control, remove tape from blower door switch, and re-install blower door.

6.Operate furnace per instruction on outer door.

7.Verify furnace shut down by lowering thermostat setting below room temperature.

8.Verify that furnace restarts by raising thermostat setting above room temperature.

START-UP PROCEDURES

I.GENERAL

1.Furnace must have a 115-v power supply properly con- nected and grounded. Proper polarity must be maintained for correct operation.

—36—

If not previously done, purge lines after all connections have been made and check for leaks.

IV. ADJUSTMENTS

A. Set Gas Input Rate

Furnace gas input rate on rating plate is for installations at altitudes up to 2000 ft.

In the U.S.A., the input ratings for altitudes above 2000 ft must be reduced by 2 percent for each 1000 ft above sea level.

In Canada, the input ratings must be derated by 5 percent for altitudes of 2000 ft to 4500 ft above sea level.

Furnace input rate must be within ±2 percent of input on furnace rating plate adjusted for altitude.