Lennox International Inc EL180UHE Service, FIGURE Constant Torque Motor, Blower Speeds, Filters

			HEAT FAN‐OFF TIME IN SECONDS
					NO JUMPER
	To adjust fan-off timing, reposition jumper across pins to
					achieve desired setting.
60 Second				90 Second				120 Second				180 Second
off Time				off Time					off Time				off Time
60	90	120	180	60	90	120	180	60	90	120	180	60	90	120	180

FIGURE 32

Constant Torque Motor

EL180UHE units are equipped with a constant torque ECM motor. It has a DC motor coupled to an electronic control module both contained in the same motor housing. The mo­ tor is programmed to provide constant torque at each of the five selectable speeds. The motor has five speed taps. Each tap requires 24 volts to energize.

Input Voltage Requirements

The circuit is designed to be operated with AC voltage. A voltage of 12 to 33VAC is required to energize the motor. Expected current draw will be less than 20mA.

Blower Speeds

Follow the steps below to change the blower speeds.

1 - Turn off electrical power to furnace.

2 - Remove blower access panel.

3 - Disconnect existing speed tap at integrated control speed terminal.

NOTE - Termination of any unused motor leads must be insulated.

4 - Place unused blower speed tap on integrated control “PARK” terminal or insulate.

5 - Refer to blower speed selection chart on unit wiring dia­ gram for desired heating or cooling speed. See Product Specifications manual for blower performance data.

6 - Connect selected speed tap at integrated control speed terminal.

7 - Resecure blower access panel.

8 - Turn on electrical power to furnace.

9 - Recheck temperature rise.

Electronic Ignition

The integrated control has an added feature of an internal Watchguard control. The feature serves as an automatic re­ set device for integrated control lockout caused by ignition failure. This type of lockout is usually due to low gas line

pressure. After one hour of continuous thermostat demand for heat, the Watchguard will re-set and remake thermostat demand to the furnace and automatically reset the inte­ grated control to begin the ignition sequence.

Service

WARNING

ELECTRICAL SHOCK, FIRE,

OR EXPLOSION HAZARD.

Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage.

Improper servicing could result in dangerous opera­ tion, serious injury, death, or property damage. Before servicing, disconnect all electrical power to furnace.

When servicing controls, label all wires prior to dis­ connecting. Take care to reconnect wires correctly. Verify proper operation after servicing.

At the beginning of each heating season, a qualified techni­ cian should check the system as follows:

Blower

Check the blower wheel for debris and clean if necessary. The blower motors are prelubricated for extended bearing life. No further lubrication is needed.

WARNING

The blower access panel must be securely in place when the blower and burners are operating. Gas fumes, which could contain carbon monoxide, can be drawn into living space resulting in personal inju­ ry or death.

Filters

All EL180UHE filters are installed external to the unit. Fil­ ters should be inspected monthly. Clean or replace the fil­ ters when necessary to ensure that the furnace operates properly. Replacement filters must be rated for high veloc­ ity airflow. Table 1 lists recommended filter sizes.

Flue And Chimney

1 - Check flue pipe, chimney and all connections for tight­ ness and to make sure there is no blockage.

2 - Check unit for proper draft.

Electrical

1 - Check all wiring for loose connections.

2 - Check for the correct voltage at the furnace (furnace operating). Correct voltage is 120VAC + 10%.

3 - Check amp-draw on the blower motor with blower ac­ cess panel in place.

Unit Nameplate__________Actual__________

Cleaning the Burners

NOTE - Use papers or protective covering in front of the fur­ nace during cleaning.

1 - Turn off both electrical and gas power supplies to fur­ nace.

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