I know the answer may be "well, it's model-specific" or something like that, but I'm hoping it's more general than that.

This house is about 25 years old, gas logs in the living room. There's a switch on the wall, next to the mantel. When the logs are lit, changing that switch essentially changes from "pilot only" (in the off/down position) to "pilot and flame, gimme some heat" (on/up).

My parents just bought a house -- new construction -- haven't gotten fully moved in yet. Similarly, there's a switch on the wall next to the mantel. I haven't toyed with it yet.

Mom's just about convinced that the gas logs won't work without electricity, because there's a switch on the wall. Given the way the setup in my house works, I'm not sure she's correct. But her concern is that the logs won't work right if there's a power outage.

I can see some of the wire that comes off the back of my insert, and it appears to head in the direction of the switch on my wall. I don't see any other electrical-looking wires going to the insert. I can't see the back of their setup at all.

So. Am I correct in thinking the switch is simply a "mode" switch for the logs? Perhaps so as to set the system to pilot-only while out for the day, for instance? Or am I totally off-base, and gas logs need electricity to operate a solenoid to control gas flow? Or am I even more wrong than that?

My setup uses batteries to turn flame on when it’s on the automatic thermostat function.
Manual setting does not require electrical power but you have to turn knobs to adjust heat.

Works without electric unless there's a setup that works differently than mine (about 15 years old).

If you want to know for sure, turn off the main power to the house and try it.

My gas logs will operate without power; that's when I appreciate them the most - when there's a power outage on a really cold day.
I have an 'on /off' rocker switch on the wall for the logs.
The only thing I need power for is the blower fan.

If the fireplace has a standing pilot (flame) for ignition then you don't need power to operate the fireplace. The pilot in addition to lighting the fireplace, is heating a thermocouple generating a small electrical charge to allow the gas valve to function. See Seebeck effect. Flipping the switch completes another circuit to actuate the gas valve.

Might be for a blower . Can't hurt to try it .

quote:

Originally posted by 686Owner:
If you want to know for sure, turn off the main power to the house and try it.

Yep, that's on my Saturday list.

quote:

Originally posted by Expat:
If the fireplace has a standing pilot (flame) for ignition then you don't need power to operate the fireplace. The pilot in addition to lighting the fireplace, is heating a thermocouple generating a small electrical charge to allow the gas valve to function. See Seebeck effect. Flipping the switch completes another circuit to actuate the gas valve.

That's the way I was thinking it works. And thank you for the Seebek reference.

quote:

Originally posted by selogic:
Might be for a blower . Can't hurt to try it .

No blower on mine. It'd be a nice thing, though, so as to spread the heat instead of just heating up the brick surround, haha.


Thanks, all!

quote:

Originally posted by Expat:
If the fireplace has a standing pilot (flame) for ignition then you don't need power to operate the fireplace. The pilot in addition to lighting the fireplace, is heating a thermocouple generating a small electrical charge to allow the gas valve to function. See Seebeck effect. Flipping the switch completes another circuit to actuate the gas valve.

Exactly right.

Not being able to use it during a power outage was my concern when I bought my new house with a similar setup, and that is what I discovered when I researched it.

So you can reassure her that no external electricity is required for the logs to function. The switch is just completing a circuit for the gas logs' self-generated milliamps, and that works even if the power is off to the house.


On a side note: My last house's gas log setup didn't have a wall switch to toggle between pilot and on, but my new one does. I don't really see the point of using the switch to put it in pilot-only... I'd rather just turn the gas logs all the way off when I'm done or I'm leaving, and turn them all the way back on again when I want to fire it back up, just like I did before.

I guess if you're the kind of person who turns the logs on and off multiple times over a short period, it might save a little wear on the starter? Other than that, doesn't seem to have a whole lot of uses.

The wire may be for the spark igniter that’s next to the pilot light.

50/50

But I'd bet on it requiring electricity.

There are two types of gas logs (not counting the ones with a manual valve), ones in which the pilot light is normally on, and ones that light the pilot light before turning on the gas valve.

In the first one, the pilot light is lit by ignitor when the gas valve knob is in the pilot position. After the pilot light is on long enough for the thermocouple to generate sufficient voltage to keep the pilot light on, the gas valve knob is turned to the on position. At that point a contact closure switch (either a rocker switch near the gas valve or a wall switch) is used to turn the logs on or off.

The second type is an electronic ignition gas fireplace, in that case voltage from the house is used to light the pilot light when the wall switch is turned on and after the pilot light flame is proven that gas valve turns on to light the logs. It normally has a place for batteries to operate the sparker when power is out.

I had a 2008 built house that had a gas fireplace with fake logs. To turn it on, I flip the switch close by. To turn off the flames, I flip the switch down. It would have had to operate by a solenoid controlling the gas line. I don't think it had a pilot light; it had a spark generator and that may have been controlled by a thermocouple.

quote:

Originally posted by bwl5:
There are two types of gas logs (not counting the ones with a manual valve), ones in which the pilot light is normally on, and ones that light the pilot light before turning on the gas valve.

In the first one, the pilot light is lit by ignitor when the gas valve knob is in the pilot position. After the pilot light is on long enough for the thermocouple to generate sufficient voltage to keep the pilot light on, the gas valve knob is turned to the on position. At that point a contact closure switch (either a rocker switch near the gas valve or a wall switch) is used to turn the logs on or off.

The second type is an electronic ignition gas fireplace, in that case voltage from the house is used to light the pilot light when the wall switch is turned on and after the pilot light flame is proven that gas valve turns on to light the logs. It normally has a place for batteries to operate the sparker when power is out.

Thank you for that description. Mine is like the first case you listed; I'm not sure whether their pilot stays lit or not. I do know now what to look for when I visit there next.

We have gas logs installed in our fireplace many years ago for backup heat, along with a gas heater in the basement.

No switch on the wall, but a rotary knob on the log front which both required to light the pilot, and adjust the flame once lit.

All moot now, since we installed a Generac this year.

Expat nailed it. If there’s a pilot it requires NO electricity. Sometimes there’s a second switch for a fan which the fan will obviously need power. These things are great in power outages. My wife wouldn’t believe me either. It wasn’t until the guy servicing it explained it exactly the way I did that she kinda believed it. Lol

Our gas logs have a constant pilot light. We have a battery operated remote that fires the logs. Our switch on the wall of the fireplace is for the fan only.

As stated in another post, great during power outages.