Gas log installation and replacement in North Quarter

Minimum firebox size for each burner

Every burner has a smallest fireplace it can go into. In one maker's table, the 18/20 inch burner calls for a firebox no narrower than 26 inches across the front and 20 across the back, at least 15 inches deep and 17 inches tall.

Its 24 inch burner needs 30 inches at the front and 24 at the back, and its 30 inch burner 36 and 29, with the same depth and height. Our crew measures all four dimensions in your firebox and compares them with the table for the set you want.

• Front width
• Rear width, measured at the burner's depth
• Depth from the opening
• Height of the opening

Ventilation air and mildew

Moisture has to go somewhere. One vent-free manual warns that installing the heater in a room without enough ventilation air may cause mildew to form from too much moisture.

The same manual sends the installer to its section on air for combustion and ventilation, which works out whether a space counts as confined. Our crew does that calculation for your room and explains the result, since a room that passes the volume rule can still need more air.

Running a vent-free set with the damper open

Some vent-free sets can also be run as vented appliances. One manual says that in that case the damper must always be open, a damper clamp accessory is installed and the thermostat function is prohibited, so the set is operated manually.

Running vented also removes the need for noncombustible facing above the opening in that manual. Our specialists explain when this configuration makes sense for your fireplace and set it up so nobody closes the damper by mistake.

A kinked connector and a low flame

The flexible connector between the valve and the burner can kink if it is bent too tightly when the pan is set in place. One maker lists a blockage or kink in the connector, the plumbing or the burner orifice as a cause of low flame height and says a kinked connector must be replaced.

Our crew routes the connector with gentle bends, checks it after the pan is seated and replaces any connector that has been crushed or folded.

When the log set pilot keeps dropping out

When a log set pilot lights and then drops out, one maker's troubleshooting table points to several parts. Our technicians check each one before recommending a repair.

Pilot parts are specific to the valve, so replacements come from the set's own parts list.

• A valve that will not hold
• A pilot hood bent away from the thermocouple
• A bent or kinked pilot line
• A loose, cracked or worn thermocouple
• Excessive downdraft in the chimney