Bryant 350MAV user manual Speed Selection, III. Cleaning Burners

1.Turn off electrical supply to furnace.

2.Remove main furnace door and blower access panel.

3.Disconnect blower motor wires from furnace control. Field thermostat connections may need to be disconnected depending on their length and routing.

4.Remove control box mounting screws, and position control box, transformer, and door switch assembly to right side of furnace casing.

5.If condensate trap is located in left- or right-hand side of furnace casing, proceed to item 6, otherwise remove trap and tubing as described below (see Fig. 8, top left):

a.Disconnect field drain connection from condensate trap.

b.Disconnect drain and relief port tubes from condensate trap.

c.Remove condensate trap from blower shelf.

6.Remove screws securing blower assembly to blower shelf and slide blower assembly out of furnace.

7.Clean blower wheel and motor by using a vacuum with soft brush attachment. Be careful not to disturb balance weights (clips) on blower wheel vanes. Do not bend wheel or blades as balance will be affected.

8.If greasy residue is present on blower wheel, remove wheel from the blower housing and wash it with an appropriate degreaser. To remove wheel:

a.Mark blower wheel location on shaft before disassembly to ensure proper reassembly.

b.Loosen setscrew holding blower wheel on motor shaft.

NOTE: Mark blower mounting arms and blower housing so each arm is positioned at the same hole location during reassembly.

c.Mark blower wheel orientation and cutoff plate location to ensure proper reassembly.

d.Remove screws securing cutoff plate and remove cutoff plate from housing.

e.Remove bolts holding motor mounts to blower housing and slide motor and mounts out of housing. Disconnect capacitor and ground wire attached to blower housing before removing motor. Motor mounts need not be removed from motor.

f.Remove blower wheel from housing.

CAUTION: The blower wheel should not be dropped or betn as balance will be affected.

g. Clean wheel per instructions on degreaser cleaner. Do not get degreaser in motor.

9.Reassemble motor and blower wheel by reversing items 8b through 8f. Ensure wheel is positioned for proper rotation. Be sure to attach ground wire. Tighten set-screw to 140 to 160 in.-lb torque.

10.Reinstall blower assembly in furnace.

11.Reinstall control box, transformer, and door switch assem- bly on blower shelf.

12.Reinstall condensate trap and tubing if previously removed.

a.Reinstall condensate trap in hole in blower shelf.

b.Connect condensate trap drain tubes. See Fig. 8 or tubing diagram on main furnace door for proper tube location.

NOTE: Ensure tubes are not kinked or pinched, as this will affect operation.

(1.) Connect 1 tube (blue or blue and white striped) from collector box.

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(2.) Connect 1 tube (violet or unmarked) from inducer housing.

(3.) Connect 1 tube (relief port, green or pink) from collector box.

c. Connect field drain to condensate trap.

13.Reconnect wires.

Refer to furnace wiring diagram and connect thermostat leads if previously disconnected. (See Fig. 15.)

NOTE: Refer to Table 1 for motor speed lead reconnection if leads were not identified before disconnection.

CAUTION: Heating speed selection MUST be adjusted to provide proper temperature rise as specified on the rating table. Failure to adjust the heating speed may shorten heat exchanger life.

TABLE 1—SPEED SELECTION

COLOR	SPEED	FACTORY
		ATTACHED TO
Black	High	Cool
Yellow (When Present)	Medium High	Spare
Blue	Medium Low	Heat
Red	Low	Spare
White	Common	Com

14.Turn on electrical supply. Manually close blower access door switch. Use a piece of tape to hold switch closed. Check for proper rotation and speed changes by perroming a componenet self-test as shown at the bottom of Service Label. (See Fig. 17.)

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

15.If furnace is operating properly, release blower access door switch, replace blower access door, and replace main furnace door.

III.CLEANING BURNERS

The following items should be performed by a qualified service technician. If the burners develop an accumulation of light dirt or dust, they may be cleaned by using the following procedure:

1.Turn off gas and electrical supplies to furnace.

2.Remove main furnace door.

3.Remove burner box cover.

4.Using backup wrench, disconnect gas supply pipe from furnace gas control valve.

CAUTION: Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation.

5.Remove wires from gas valve. Note location for reassem- bly.

6.Remove burner box pressure tube from gas valve regulator fitting.