Adams Condensing Oil-Fired Furnace Xii. Normal Sequence Of Operation, Heating Mode, Fan Only Mode

Circulator Blower Speeds

Low	Red
Medium	Blue
Hiah	Black
Common/Neutral	White

XII. NORMAL SEQUENCE OF

OPERATION

POWER UP MODE

The normal power up sequence is as follows:

•115 VAC power applied to furnace

•Furnace awaits call from thermostat

HEATING MODE

The normal operational sequence in heating mode is as follows:

•Rand W thermostat contacts close, initiating a call for heat

Closure of the thermostat switch through relay #1 energizes primary control on the burner. Primary control goes in the pre-purge cycle, runs for 15 seconds and then goes into ignition sequence, burner ignites.

Blower operation is controlled by Blower Delay "On-Oft" Control Relay, mounted in control panel face of blower.

With factory setting (DELAY ON MAKE) of (30 sec), approximately 30 seconds after burner ignites, blower relay energizes to run comfort blower in the heating speed mode.

NOTE:

Blower speed (heating) is factory set on high speed.

THERMOSTAT SATISFIED

When the thermostat satisfied, heat contact opens through relay No.1, primary control relay drops out, which de-energizes the primary control. Burner goes into post-purge cycle, and then shuts off. With factory setting (DELAY ON BREAK) of 600 seconds, comfort blower continues to run for approximately 390-600 seconds after burner is satisfied.

FAN ONLY MODE

The normal operational sequence in fan only mode is as follows:

•Rand G thermostat contacts close, initiating a call for fan

•Circulator blower is energized

•Circulator blower runs

•Rand G thermostat contacts open, completing the call for fan

•Circulator blower is de-energized

•Furnace awaits next call from thermostat

COOLING MODE

When the heat-cool switch is in the cool position, and the thermostat calls for cooling, 24 volts AC at C and Y will complete the circuit to contactor in condensing unit.

XIII. TROUBLESHOOTING

IMPORTANT:

DUE TO THE POTENTIAL HAZARD OF LINE VOLTAGE, ONLY A TRAINED, EXPERIENCED SERVICE TECHNICIAN SHOULD PERFORM THE TROUBLESHOOTING PROCEDURE.

PRELIMINARY STEPS:

Check the diagnostic light for indications of burner condition. Refer to R7184 LED Diagnostic Light section for details.

CAUTION!

When simulating a call for heat at the R7184, disconnect at least one thermostat lead wire from the T - T/3 terminals to prevent damage to the thermostat. Neglecting this procedure may burn out the heat anticipator of a standard 24 VAC thermostat, or cause harm to components of a micro­ electronic thermostat.

19