Heating

Dallas Fort Worth Furance HVAC

Possible Causes

Thermostat set too low and not calling for heat

Thermostat not workingFurnace Repair keller

Circuit breaker or fuse controlling the furnace is tripped or blown

Natural gas or propane control valve is closed

Pilot light is out

Possible Repairs

Check that thermostat is in heat mode and has appropriate temperature setting

Try moving dial setting up or down a few degrees

Clean contacts in thermostat if it is a non-digital type

Reset tripped circuit breaker

Replace blown fuse

Relight pilot light

Gas Furnace Does Not Produce Enough Heat

Possible Causes

Dirty furnace air filter

Gas burners may be dirty or need adjustmentAir-Conditioning and Heating Installation

Possible Repairs

Replace dirty air filter

Call furnace service technician to have burners adjusted.

Gas Furnace Comes On and Off Too Frequently

Possible Causes

Dirty furnace air filter

Blower motor problem

Thermostat problem (heat anticipator)

HVAC RepairPossible Repairs

Adjust thermostat heat anticipator

See also Troubleshooting a Thermostat

Replace dirty air filter

Oil blower motor lubrication ports (usually at each end of shaft) with light weight oil

Check for proper belt tension. Belt should depress about 1″ at center of span.

If too loose, tighten belt.

Replace frayed belt.

Blower Does Not Turn Off – Always Running

Possible Causes

Thermostat set to fan continuous

Faulty fan limit control switch on furnace (if thermostat has no fan setting)

Possible Repairs

Change thermostat fan setting

Reset or replace furnace fan limit control switch

Gas Furnace Has Noisy Operation

Possible Causes

Higher pitched “squealing” sound may be caused by slipping blower belt or motor or shaft bearings in need of oiling

Lower pitched “rumble” sound may be caused by a poorly adjusted pilot light if this problem occurs with the burners off.

Lower pitched “rumble” sound may be caused by dirty gas burners if the problem occurs with the burners on.

Possible Repairs

Oil blower motor lubrication ports (usually at each end of shaft) with light weight oil

Check for proper belt tension. Belt should depress about 1″ at center of span.

If too loose, tighten belt.

Replace frayed belt.

Adjust pilot light

Call furnace service technician to have burners adjusted or cleaned.

Lighting a Gas Furnace Pilot

Possible Causes

A pilot can go out due to a strong draft, dirty orifice or dirt in the gas tube.

The thermocouple may also be faulty and is shutting off the gas supply.

Possible Repairs

For an overview on the gas furnace pilot and how to troubleshoot, repair and relight it, please see Gas Furnace Pilot and Thermocouple. Also see the tutorial How to Replace a Thermocouple.

Electronic Ignition Furnace Problems

Newer furnaces do not rely on a standing pilot to ignite the gas burners. Electronic ignition occurs typically in one of two ways:

Intermittent Pilot, or

Hot Surface Ignition

The intermittent pilot system uses an electronically controlled high voltage electrical spark to ignite the gas pilot and then subsequently the main burners, when the thermostat calls for heat.

The hot surface ignition system uses an electronically controlled resistance heating element not unlike a light bulb filament (and shown in the photo above), to ignite the gas burner.

See the Tutorial Overview and Repair of the Electronic Ignition Furnace for troubleshooting repair tips for electronic ignition furnaces.

Mismatching the Furnace and Thermostat:

Furnaces and thermostats are not mix and match appliances. Using the wrong type of thermostat with a furnace will cause operating problems and can be dangerous. Although thermostats look similar they are designed vary differently.

There are numerous types of heating systems and thermostat systems and they need to be coordinated for safe and proper operation.

Review the tutorial Thermostat and Furnace Compatibility to understand the three types of thermostat systems used today:

Millivoltage

Low Voltage

Line Voltage

Thermostat Troubleshooting and Repair

Some common symptoms exhibited by the furnace may actually be due to a faulty thermostat. After you have confirmed that the furnace is not the problem, you’ll want to check the thermostat.

Thermostat problems can show up as a furnace that produces no heat, wild temperature swings or cycling on and off too often. As described in the previous section Thermostat and Furnace Compatibility, you need to determine what type of thermostat you have for your furnace.

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200 S Main St, keller tx