Carrier 48VT(N) Limit Switch, Burner Ignition, Induced Draft combustion air Blower Assembly

Fan Partition	Flue
Mounting	Collector	Inducer
Bracket	Box
		Blower
		Housing

Integrated Gas Unit Controller (IGC)

Auto Transformer

fuses used on 460

volt units only.

(Hidden)

Interface Fan Board (IFB)

Induced Draft

Motor

Rollout

Burner Mounting Switch

Rack Screw

directions in the Induced Draft Blower Assembly section.

2.Remove the 11 screws holding the flue collector box cover (See Fig. 18) to the heat exchanger assembly. Inspect the heat exchangers.

3.Clean all surfaces, as required, using a wire brush.

Limit Switch

Remove blower access panel (see Fig. 19). Limit switch is located on the fan partition.

Burner Ignition

Unit is equipped with a direct spark ignition 100 percent lockout system. Ignition module (IGC) is located in the control box (See Fig. 18). Module contains a self-diagnostic LED. During servicing, refer to label diagram or Table 5 in these instructions for

48VT-- A

A09199

Fig. 18 - Blower Housing and Flue Collector Box

		Control
	Blower	Access
		Panel
Compressor	Access
Access Panel	Panel

A09210

Fig. 19 - Unit Access Panels

Induced Draft (combustion air) Blower Assembly

The induced-draft blower assembly consists of the inducer motor, the blower housing, and the induced-draft blower wheel.

Clean periodically to assure proper airflow and heating efficiency. Inspect blower wheel every fall and periodically during the heating season. For the first heating season, inspect blower wheel bimonthly to determine proper cleaning frequency.

To inspect blower wheel, remove draft hood assembly. Shine a flashlight into opening to inspect wheel. If cleaning is required, remove induced-draft blower assembly as follows:

1.Remove control access panel (See Fig. 19).

2.Remove the 5 screws that attach induced-draft blower as- sembly to the flue collector box cover.

3.Slide the assembly out of the unit. (See Fig. 20). Clean the blower wheel. If additional cleaning is required, continue with Steps 4 and 5.

4.To remove blower wheel, remove 2 setscrews.

5.To remove inducer motor, remove screws that hold the inducer motor to the blower housing.

6.To reinstall, reverse the procedure outlined above.

Flue Gas Passageways

To inspect the flue collector box and upper areas of the heat exchanger:

1. Remove the induced draft blower assembly according to

LED interpretation.

If lockout occurs, unit may be reset by either momentarily interrupting power supply to unit or by turning selector switch to OFF position at the thermostat.

Main Burners

At the beginning of each heating season, inspect for deterioration or blockage due to corrosion or other causes. Observe the main burner flames and adjust, if necessary.

Removal of Gas Train

To remove the gas train for servicing:

1.Shut off main gas valve.

2.Shut off power to unit and install lockout tag.

3.Remove control access panel (See Fig. 19).

4.Disconnect gas piping at unit gas valve.

5.Remove fan partition mounting bracket (2 screws located on the left side of control compartment on the fan partition panel). Slide bracket forward, bottom first to remove. (See Fig. 18).

6.Remove wires connected to gas valve. Mark each wire.

7.Remove ignitor and sensor wires at the ignitor module.

8.Remove the mounting screw that attaches the burner rack to the unit base (See Fig. 18).

9.Slide the burner rack out of the unit (See Fig. 18 and 21).

10.To reinstall, reverse the procedure outlined above.

Outdoor Coil, Indoor Coil, and Condensate Drain Pan

Inspect the outdoor coil, indoor coil, and condensate drain pan at least once each year. The coils are easily cleaned when dry; therefore, inspect and clean the coils either before or after each cooling season. Remove all obstructions, including weeds and shrubs, that interfere with the airflow through the condenser coil.

Straighten bent fins with a fin comb. If coated with dirt or lint, clean the coils with a vacuum cleaner, using the soft brush attachment. Be careful not to bend the fins. If coated with oil or grease, clean the coils with a mild detergent-and-water solution. Rinse coils with clear water, using a garden hose. Be careful not to splash water on motors, insulation, wiring, or air filter(s). For best results, spray outdoor coil fins from inside to outside the unit. On units with an outer and inner condenser coil, be sure to clean between the coils. Be sure to flush all dirt and debris from the unit base.

Inspect the drain pan and condensate drain line when inspecting the coils. Clean the drain pan and condensate drain by removing all foreign matter from the pan. Flush the pan and drain tube with clear water. Do not splash water on the insulation, motor, wiring, or air filter(s). If the drain tube is restricted, clear it with a “plumbers snake” or similar probe device. Ensure that the auxiliary drain port above the drain tube is also clear.

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