Troubleshooting: Cooling Sequence of Operation

COOLING SEQUENCE OF OPERATION

NORMAL COOLING MODE

 

 

ABNORMAL COOLING MODE

 

 

 

 

 

 

 

 

 

 

 

 

POWER ON

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IGNITION CONTROL MAIN POWER ON.

 

 

 

 

 

 

 

 

 

 

NO

 

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

 

CONTROL SELF DIAGNOSTIC CHECK.

 

INDOOR BLOWER OFF WITH NORMAL DELAY.

 

IS CONTROL OPERATING NORMALLY?

 

 

SIGNAL CIRCUIT BOARD FAILURE AT LED.

 

 

 

YES

 

 

 

 

INTERRUPT MAIN POWER TO RESET CONTROL.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

LED FLASHES CODE 2 IMPROPER GROUND

 

IS THERE A PROPER GROUND?

 

 

CONTROL WILL CONTINUE TO CALL FOR COOLING

 

 

 

YES

 

 

 

 

IN THIS CONDITION.

 

 

 

 

NO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LED FLASHES CODE 1 POLARITY REVERSED

 

 

 

 

 

 

 

 

 

IS POLARITY CORRECT?

 

CONTROL WILL CONTINUE TO CALL FOR COOLING IN

 

 

 

 

 

 

YES

 

 

 

 

THIS CONDITION.

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

IS VOLTAGE

 

 

 

LED FLASHES CODE 13 LOW VOLTAGE. CONTROL

 

 

 

 

 

 

 

 

 

ABOVE 70 VOLTS?

 

 

 

WILL CONTINUE TO CALL FOR COOLING

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

IN THIS CONDITION.

 

 

 

 

 

 

 

 

 

 

 

NO

 

LED FLASHES CODE 8 ROLLOUT SWITCH OPEN. GAS

 

 

 

 

 

 

 

 

 

 

 

 

VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR

ROLLOUT SWITCH MONITORED CONTINUOUSLY.

 

 

 

 

BLOWER ON. SEQUENCE HOLDS UNTIL ROLLOUT SWITCH

IS ROLLOUT SWITCH CLOSED?

 

 

 

CLOSES AND MAIN POWER IS INTERRUPTED OR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THERMOSTAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LED: SLOW FLASH RATE REMAINS UNCHANGED

THROUGHOUT COOLING CYCLE.

THERMOSTAT CALLS FOR COOLING.

COMPRESSOR CONTACTOR AND SYSTEM FAN

ENERGIZED WITH 2-SECOND DELAY

(COOLING SPEED). EAC TERM. ENERGIZED.

THERMOSTAT OPENS.

COMPRESSOR OFF.

SYSTEM FAN AND EAC TERM. OFF

WITH 45-SECOND DELAY.

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Lenox Lennox Merit Series Gas Furnace Upflow/Horizontal air discharge, ML180UHE Cooling Sequence of Operation

Lennox Merit Series Gas Furnace Upflow/Horizontal air discharge, ML180UHE specifications

The Lenox ML180UHE is a reliable and efficient gas furnace that falls within the Lennox Merit Series. This model is designed for upflow or horizontal air discharge, making it versatile for various installation requirements. With its robust construction and advanced technology, the ML180UHE is ideal for homeowners seeking a dependable heating solution that combines comfort and efficiency.

One of the main features of the ML180UHE is its impressive 80% Annual Fuel Utilization Efficiency (AFUE) rating. This efficiency means that 80 cents of every dollar spent on fuel is used to heat your home while minimizing waste. This furnace is equipped with a multi-speed blower motor that enhances the overall air circulation in your home, providing consistent temperatures and improved comfort.

The ML180UHE features a durable heat exchanger made of high-quality materials, which ensures longevity and reliable performance. The design of the heat exchanger maximizes heat transfer efficiency, allowing the furnace to quickly warm your home while also maintaining optimal efficiency levels throughout its lifespan.

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