Gas Fireplace Valve Replacement in Sioux Falls

A gas fireplace valve is replaced when testing shows it is the part that has failed, and in Sioux Falls that typically runs $500 to $1,000 installed. The diagnostic call before it typically runs $150 to $300. We test before we condemn a valve, because a weak thermocouple, thermopile, wire run or low supply pressure can make a good valve look dead, and those fixes usually cost less.

Testing before replacing

A valve is the most expensive common part on a gas fireplace, so we prove it first:

• Inlet pressure. A manometer on the inlet test port. Napoleon’s GD33 manual says it should read 7 inches water column (minimum 4.5) for natural gas, or 13 inches (minimum 11) for propane.
• Outlet pressure. Napoleon gives 3.5 inches water column for natural gas and 10 inches for propane. Other makes have their own figures on the rating plate or in the manual.
• The circuit. On a millivolt valve we read the thermocouple and thermopile output and the wall switch loop. On an electronic valve we test the board’s signal to the valve.

Good inlet, good circuit, wrong outlet: that is usually a valve.

Supply problems that look like a valve

Sometimes the fireplace is fine and the gas supply is short. Napoleon’s troubleshooting list says that when the pilot goes out on its own, gas piping may be undersized: turn on all gas appliances and see if the pilot flame flutters, diminishes or goes out, especially when the main burner ignites. A low inlet reading with the furnace and water heater running points at the piping, not the valve.

The City of Sioux Falls homeowner guide also warns that some homes have gas supplied at 2 PSI, which it says is about five times higher than the operating range of most appliance valves. Those systems use a regulator ahead of the appliances, so a valve that keeps failing in that kind of house is a reason to read the supply first.

Natural gas or propane

Natural gas and propane valves are not interchangeable without the right conversion parts for that model. We order from the rating plate.

Reconnecting the gas line

When a valve is replaced the gas connection is opened and made up again. The City of Sioux Falls homeowner guide says reconnecting a gas line for an appliance replacement does not need an air pressure test, but those joints must be checked for leaks with a gas detector or soap bubbles. It also says every appliance needs its own dedicated shutoff with a union fitting or listed flexible connector, and a drip leg or sediment trap at each appliance.

Two connector checks matter while the connection is open. MidAmerican Energy says uncoated brass connectors no longer meet modern safety standards and tells customers not to replace them themselves. And if your home has corrugated stainless steel tubing (CSST), common in homes built after 1990, MidAmerican says to contact a licensed electrician to confirm a bonding device is installed.

Who does the work

Inside Sioux Falls, the city says anyone paid for mechanical work must be employed by a city-licensed mechanical contractor, and it licenses fireplace contractors separately. South Dakota’s plumbing statute defines plumbing as water, drainage, venting and sewer work and does not mention gas, so the state plumbing licence does not by itself answer who may do gas work. Ask which city licence covers the valve and gas connection, and who is pulling any permit. Outside the city, check with the town’s building office.

If you smell gas, leave the house and call MidAmerican Energy, or Crooks Municipal Gas in Crooks and Renner, and 911 from outside before anyone touches the valve. Related: pilot and ignition repair, smell of gas, pricing, and the Crooks and Renner page.