Gas Fireplace Diagnostics and Troubleshooting

Follow these steps for diagnosing and troubleshooting Gas Fireplaces repairs.

For the average DIYer, this may seem intimidating, depending on the problem; however, there are some basic symptoms, cause, and remedies you can troubleshoot on your own without too much trouble.

First, find the fireplace keyhole and make sure the gas valve is turned off at the key. This is always located right next to your fireplace.

Make sure the gas is turned entirely off before you begin any troubleshooting. If the gas has been on recently, open a window and wait a few minutes.

The following tasks are to troubleshoot your fireplace with remedies and repairs on some basic problems.

No Pilot Light, Pilot will light but goes out when the button is released
Main burner is slow to come or doesn't start sometimes
Black soot inside the fireplace and the chimney

No Pilot Light, Pilot will light but goes out when the button is released

Cause: Draft Spill Switch open.

Remedy: Your gas fireplace may be equipped with a draft switch. These can be a manual reset or auto reset. Check the vent cap for damage or bent to one side. A bent cap can cause a down draft

Cause: Draft Spill Switch open.

Remedy: There should be a least a 10' Radius clear around the vent termination. Any obstruction located around the chimney opening can create a positive pressure. Force wind to push down the chimney.

Cause: Weak Thermopile Generator

Remedy: The original Thermopile that comes with most gas fireplace will fail in the first 3-5 years. Disconnect the leads from the generator and test with a voltmeter. There should be at least 500 millivolts 0.5 VDC Any less indicates a weak generator, replace generator.

Main burner is slow to come or doesn't start sometimes

Cause: Low voltage to the gas valve

Remedy: Weak Thermopile Generator. Generator output is less than 500 mv.

Poor connection on the wiring, a dirty or loose connection will cause an excessive voltage drop, stealing power from the gas valve. Any wiring connections with marettes should be soldered, crimped with proper connectors, or tightened on a connection block or screw terminal board.

Black soot inside the fireplace and the chimney

Cause: Poor Air gas ratio, flame is burning too rich

Remedy: Flame is burning too rich increase primary air.

In order to keep the flame as attractive as possible, the primary air is kept to a minimum. Dirt build up around the air intake, dirty burners or operation at high altitude 2000 ft ++ can cause sooting. Increase primary air by locating the burner inlet and opening the shutter.

It might be a fix inlet with no adjustment and will require gas adjustment or changes to the manifold. Combustion testing equipment is required to make any changes in the gas manifold.