Propane and natural gas fireplace repair in MetroWest

Direct vent, B-vent or a log set

Three quite different gas appliances can sit behind a fireplace opening, and each is serviced to its own instructions. A sealed front, a draft hood and an open firebox fail in different ways, so a check that fits one can mislead on another.

One direct vent manual puts the difference plainly. Its units draw all of their combustion air from outside through the vent pipe, while the natural vent units in a companion manual must be installed with the draft hood in the same air pressure zone as their combustion air inlet.

At the start of a visit in MetroWest, the appliance type is the first thing named on the estimate. Vent-free units are routed to our ventless gas fireplace service, and the three types this repair service covers are these.

• A direct vent unit with a sealed glass front
• A natural vent, or B-vent, unit with a draft hood
• A decorative gas log set in a fireplace built for wood

When the pilot burns but the burner stays off

A steady pilot with no main flame means the pilot safety is holding and the fault sits further along, between the call for heat and the burner valve. On millivolt units, one maker's charts work through it in a set order.

The thermopile reading settles the last question. Low output means the pilot assembly, while adequate output with the switch on and still no burner means the valve. A pilot flame that sits too far from the thermopile is adjusted before either part is condemned.

Each result goes on the estimate, so a valve is not quoted when a loose switch wire was the real cause. Our technician runs these checks in order at your MetroWest home.

• The wall switch or remote and its connections
• The wiring between the switch and the valve
• How far the pilot flame reaches onto the thermopile
• The thermopile's output, read at the valve terminals

The burner orifice and its size

The main burner orifice, which some manuals call the injector, is a fitting with a precisely sized hole. That size sets how much gas the burner receives. The rating plate lists it, and the maker's service parts list names the right one for each model and gas.

Two things can go wrong. Soot, dirt, lint or corrosion can partly block it, and a wrong orifice can end up in the unit after earlier work or a conversion. A yearly checklist from one manufacturer covers both, asking the technician to inspect the orifice for soot, dirt and corrosion and to confirm its size against the parts list, and other manuals add clearing lint from around the injector.

During a repair in MetroWest, the orifice is checked against the plate and the parts list. A dirty one is cleaned as the manual allows, and a wrong or damaged one is replaced with the listed part and shown on the estimate as its own line.

Leak checks on the appliance connections

A yearly service list we follow includes a leak check of every accessible gas-carrying tube, connection and fitting. The fuel gas code allows leaks to be located with an approved gas detector, a noncorrosive leak detection fluid or another approved method, and the fireplace manuals add that an open flame is never used.

One natural vent manual also warns against spraying solution onto the control body, and notes that excess pipe compound can set off an electronic detector. A leak on the appliance's own valve, pilot or burner joints is part of the fireplace repair, while one on the connector or the supply piping is referred to the plumber or gas installer who works on house piping.

Any fitting disturbed during a repair is checked before the fireplace is lit again, as the installation manuals direct. On repair and service visits in MetroWest, our technician uses that manual's list of points as a guide.

• The pipe from the supply connection to the gas valve
• Every joint on the valve and control body
• The burner and pilot connections
• Field-made and factory-made joints alike