Understanding HOW Your Furnace Works

WARNING

Never store anything combustible near or on your furnace. These include brooms, dustmops, vacuum cleaners, other cleaning tools or items, plastic or plaxtic containers, paper bags or other paper products. A fire could occur resulting in damage, injury or death.

2.3. ALTERATION OF FURNACE CONTROLS

WARNING

Do not alter any gas or electrical controls (gas control, pilot or safety controls) in any manner. Altering them could cause furnace to operate unsafely resulting in damage, injury or death.

SECTION 3 • UNDERSTANDING HOW YOUR FURNACE WORKS

Your installer should have given you a detailed explanation of how the furnace operates. Shown below are the basic operation characteristics and sequence of operation. If you have any questions consult your installer and/or service agency.

* * IMPORTANT * *

There are many types of thermostats compatible with this furnace. Make sure you understand the specific type installed. Ask installer for detailed explanation, and retain thermostat instruction manual for reference.

This furnace is equipped with a vent shut-off system which monitors the combustion air into the burners by means of a pressure sensing device. When the vent becomes blocked, this device turns off the gas valve circuit to prevent flue products from entering the structure. In the event that this occurs, shut off furnace and contact a qualified service agency.

3.1BASIC OPERATION – HEATING CYCLE

This furnace is operated by an Electronic Blower Control (EBC) and a gas control system which controls all functions of the furnace.

On a call for heat from the thermostat, the EBC first turns on the inducer motor. The pressure switch then closes signaling the ignition control to proceed with ignition function.

The ignition system consists of an intermittent pilot with a hot surface igniter to light pilot burner, senses flame, and then main gas valve opens with pilot flame lighting main burners.

There is a 60 second delay after main burner is on until the comfort air blower starts on heating (low) speed. After the thermostat is satisfied, the burners will go off as gas valve closes. The inducer will continue to run for 5 seconds, and the comfort air blower will continue to run for two minutes.

3.2BASIC OPERATION – COOLING CYCLE

On a call for cool the compressor and condenser fan will start immediately, and the comfort air blower will start 6 seconds later on cooling (high) speed. When the thermostat is satisfied the compressor and condenser fan will stop, and the comfort air blower will continue to operate for 60 seconds.

3.2.1COMPRESSOR LOCKOUT (CANADIAN UNITS ONLY)

The units built for Canadian use are equipped with high and low pressure controls. These controls protect the compressor from extreme conditions such as high refrigerant pressure or a loss of charge. When this happens the compressor is held off line by a lock out relay. To reset the lock out relay, the thermostat must be set to the “OFF” position and then returned to the normal operating position. The compressor is now allowed to function. If the compressor continues to lock out, service personnel should be called to check the unit.

3.3MANUAL FAN (CONTINUOUS AIRFLOW) OPERATION

If wall thermostat is set to MANUAL (ON) position to operate comfort air blower continuously to provide air circulation throughout the building, the blower will operate on the heating speed rather than the cooling as is typical with most systems. This permits the air to circulate as desired but helps keep the operating noise level down as well as conserving energy.

During a call for cooling, the blower automatically shifts up to cooling speed, and remains there until 60 seconds

after thermostat is satisfied then drops back to heating speed.

Manual 2100-279 Page 3

43506 specifications

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