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I have a gas fireplace, which I have not used in over 3 years. It starts with an on/off switch on the wall. When I turn it ON, nothing happens. I am kind of scared of trying anything with this as it works with gas and I don't totally understand how it works.

Any tips on checking some basic stuff to see if I can get it started before I call a professional?

  • Very basic questions: is the gas from a tank (like propane) and if so are you sure there's gas in it? – user20127 Nov 19 '14 at 0:01
  • Does the unit have a pilot light, or electronic start? There should be an access panel, have you opened it and looked inside? There will likely be instructions for operating the fireplace, inside the access panel somewhere. If not, or you're still having trouble, posting photos of what you find in the access panel might be helpful. – Tester101 Nov 19 '14 at 12:09
  • No propane tank, its a switch on the wall like a electronic light switch so I am gas is coming from pipe. – Ved Nov 20 '14 at 0:25
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It's difficult to help you troubleshoot a device, without a bit more information about it. Since you're not giving us much, I'll try to give general advice.

Depending on the system, there's a few things that could be wrong.

Gas Valve Closed

This would affect every type of gas fireplace.

Test:

  1. Locate the gas valve.
  2. Turn on the switch.
  3. Listen for the valve to open.

If you hear the valve open (click, clank, clunk, etc.), but don't hear or smell gas. The valve may be off.

Most gas valves are quarter turn ball valves, so you can tell when they're open simply by looking at the knob. The knob should have an arrow, handle, or other linear feature on it. This feature should be aligned with (parallel to) the pipe, when the valve is open.

Solution:

Turn on the gas.

No Gas

If you get your gas from a tank or bottle, you'll want to make sure you have gas.

Test:

Similar to above, except that the valve will be open.

Solution:

Fill the tank.

Bad Switch

Since the system relies on a switch to know when to turn on, a bad switch could be devastating.

Test:

  1. Label and remove the wires from the switch.
  2. Test continuity across the switch, in both positions.

When the switch is toggled on way, you should measure infinity (or not hear a beep). When the switch is toggled the other way, you should get a measurement (or hear a beep).

Solution:

Replace the switch.

Pilot Not Lit

If your system requires a pilot, and it's not lit. You can flip the switch all you want, you'll never make fire.

Test:

  1. Look at the pilot.

If you see a flame, it's lit.

Solution:

Light the pilot.

Bad Flame Sensor

Fireplaces use flame sensors (thermocouples, thermopiles, etc.), to determine if there's a flame. If the sensor goes bad, the system will not hold the gas valve open.

Test:

  1. Disconnect the thermocouple from the system.
  2. Set multimeter to measure DC millivolts (mV).
  3. Connect the black lead to the button of the thermocouple.
  4. Connect the red lead to the copper part of the thermocouple.
  5. Heat the thermocouple with a torch.

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As the thermocouple heats, you should get a reading on the multimeter.

Solution:

Replace the flame sensor.

Bad Gas Valve

If the system is getting all the right signals, but the gas valve is not opening. It could be a bad valve.

Test:

See test for Gas Valve Closed. You won't hear the valve open. You'll have to be sure the valve is getting the signal to open, so make sure all other items check out first.

Solution:

Replace the valve.

Depending on the type of fireplace, the ignition sequence will be a bit different. using the typical sequences below, you might be able to narrow down where the problem is.

Typical Gas Fireplace Ignition Sequence

Pilot

  • Switch is flipped
  • If pilot is lit (checked via a thermocouple or other flame sensor).
    • Open main burner gas valve.
    • Wait (There may be an adjustable timeout, or a hard set timeout).
    • If main burner lit (check via another thermocouple or other flame sensor).
      • Leave main gas valve open.
    • Else
      • Close main gas valve.
      • Purge system (in the case of a fireplace, this is likely a timed wait).
      • Retry ignition (this may happen 0 to many times, depending on the system).
  • Else
    • Do nothing

Electronic Ignition with pilot

  • Switch is flipped
  • Open pilot gas valve.
  • Initiate electronic ignition device (spark gap, hot surface, etc.).
  • Wait.
  • If pilot flame sensed.
    • Open main burner gas valve.
    • Wait.
    • If main burner flame sensed.
      • Hold main gas valve open.
    • Else
      • Close main gas valve.
      • Purge system.
      • Retry ignition.
      • If no ignition after retries
        • Close pilot gas valve.
        • Lockout (this may require something to be physically reset, or a simple timed lockout).
  • Else
    • Close pilot gas valve.
    • Purge system.
    • Retry ignition.
    • If no ignition after retries
      • Close pilot gas valve.
      • Lockout.

Electronic Ignition

  • Switch is flipped
  • Open main burner gas valve.
  • Initiate electronic ignition device.
  • Wait
  • If flame sensed.
    • Hold main gas valve open.
  • Else
    • Close main gas valve.
    • Purge.
    • Retry.
    • Lockout.
  • wow thanks for detailed reply, so far I think my pilot is not lit, I have lot to go over from this info so I will check and get back to you guys...thanks again – Ved Nov 20 '14 at 0:28
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It sounds like the gas was turned off somewhere. Generally, there's a knob next to the fireplace that may require a tool to turn on or off. You may also need to bleed air out of the gas lines, perhaps try the on/off switch over and over a few times and see if anything changes. It's pretty straight forward and you would smell the gas if there were a leak.

  • Some fireplaces have a pilot. Flipping the switch on and off a gajillion times won't do anything, if you don't light the pilot. – Tester101 Nov 19 '14 at 12:12
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Is the pilot lit? The wall switch will not turn the fireplace on if the pilot is not lit. Here is some general information regarding how gas appliances work (the source link below also has some pictures):

Most gas appliance will have a gas valve, a thermocouple, a thermopile, a piezo, and a pilot light. These parts are used to light and control the main burner.

A piezo spark ignition is used to ignite the pilot after the gas knob is turned to the “pilot” position and depressed. Once lit, the pilot light heats up BOTH a thermocouple and a thermopile.

The thermocouple is sometimes called a heat sensor or flame sensor. A thermocouple is a device made of two different metals which creates a small electrical charge (25 to 100 millivolts) when heated at one end by the gas pilot. A millivolt is 1/1000th of a volt. This small charge causes an electromagnet inside the gas valve to open and allow gas to flow to the pilot light. If the pilot light goes out and the thermocouple is no longer heated, it will shut down the gas flow to both the pilot and main burner.

Since the thermocouple must be heated in order to open the gas flow, fireplaces often have a startup mode, during which a pilot knob must be depressed and held for 30 seconds or so after lighting the pilot. At the end of the 30 seconds, the pilot should be generating enough heat so that the thermocouple is generating enough electricity for the gas to keep flowing to the pilot light. At this time, the startup knob can be released and the valve turned to an “on” position for appliance operation. Most fireplaces are designed to have a “standing” pilot light, which means it is always on –year round. Turning a pilot light on and off can shorten the lifespan of the thermocouple. A thermopile is a probe that contains multiple thermocouples; therefore it can produce a larger electrical current.

The thermopile circuit causes a larger electromagnet inside the main gas valve to open and allow gas to flow to the main burner. This second circuit is also powerful enough (300-600 millivolts) to allow the use of a thermostat, wall switch or control switch to operate the main valve. Control of the valve is obtained simply by hooking a pair of wires (from the switch or remote control receiver) to two terminals located on the valve.

Source: Fireplace Warehouse

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After ensuring that the gas supply is not shut, cycle the on/off switch several (maybe numerous) times to free the system of air. You should hear the electric ignitor clicking for a short time after each time you activate the switch.

If you don't hear the ignitor- stop (you may have an electrical issue).

If a strong smell of gas develops- stop (you may have a problem with the gas supply equipment).

In most locales you can call your gas utility supplier and tell them "I smell gas" and they will come and take a look at the appliance for free. If you are lucky the technician will end up giving you a free diagnosis of the problem, if you are really lucky he/she will fix it for free (or for a nominal fee) because the utility wants you to burn gas ($$).

Those units employ an electrically operated valve that opens for a short time to allow the ignitor to light the gas, a thermocouple (bi-metallic strip which generates a small electrical current when heated) sends a signal for the valve to stay open if the burner lights, but allows it to close if no heat is present.

  • Some fireplaces have a pilot. Flipping the switch on and off a gajillion times won't do anything, if you don't light the pilot. – Tester101 Nov 19 '14 at 12:12

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