Symptom

Cause

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

Draft Spill Switch open.

Pilot Light blown out from down draft in the chimney.

Weak Thermopile Generator

Your gas fireplace maybe 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

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.

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

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.

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.