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Qs: Gas Fireplace Insert Drafty

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  • Jan 18th, 2011 2:03 pm
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[OP]
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Jan 18, 2004
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Qs: Gas Fireplace Insert Drafty

Our wood burning brick fireplace was retrofitted (last owner) with a gas fireplace insert. It is drafty. I tried taking it apart to inspect it prior to winter but could not completely pull the unit out for a detailed inspection.

As far as I can tell, there is no damper to close off the exhaust. Also, the exhaust vent/liner (rigid metal accordian piping) does not appear to be completely sealed with the fireplace. It is mounted above the fireplace exhaust hole and there is a gap between the two similar to how there is a gap between a (non-high-efficiency) gas water heater and the the exhaust vent.

I cannot see a separate intake vent/liner. Its either there and I cannot see it because I haven't been able to completely remove the unit, or its drawing intake from the room. I have read up on vent types in the past. Time to go refresh my memory.

1. Should there be a gap in the exhaust there like the water heater?
2. If yes, why? I'm thinking something to do with vacuum pressure if there wasn't.
3. Is the draft normal? I'm guessing no. It would seem to be too energy inefficient if it were.
4. What to do? (Note: I hate paying for labour and prefer DIY :) )
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9 replies
Deal Guru
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Dec 12, 2009
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Could it be that you have a so called natural vent gas fireplace, meaning combustion air comes from inside the house? I would imagine that these units can be drafty unless there is a way of closing off the exhaust vent. I had my wood burning fireplace converted to gas two years ago. The unit I chose was a valor. It has two pipes going up the chimney, one for combustion air and one for exhaust. I don't have any draft issues at all.
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Feb 16, 2009
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they should have left you the owners/install manual for both the fireplace and the vent kit. Have a look at the pics in there.

The pilot light usually makes enough heat that they aren't drafty.
[OP]
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Yes, I suspect its a natural vent exhaust. If that's the way its supposed to be, then my question would be: WHY even make such a thing? Its just an energy waster.

I don't have the owner's manual and there's no model number to google a manual. I have in the past looked at manuals for other Majestic brand fireplaces, but not much help.

I don't have the pilot light on because we do not use the fireplace - under the assumption that the furnace is a more efficient method of heating than the fireplace.
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Nov 2, 2005
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I've got a Vermont Castings fireplace and the cold air most definately falls down the chimney if the pilot light is not lit.

If you're not using it why not get rid of it and block of the chimney?
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Mr Nobody wrote:
Jan 17th, 2011 12:27 pm
Yes, I suspect its a natural vent exhaust. If that's the way its supposed to be, then my question would be: WHY even make such a thing? Its just an energy waster.

I don't have the owner's manual and there's no model number to google a manual. I have in the past looked at manuals for other Majestic brand fireplaces, but not much help.

I don't have the pilot light on because we do not use the fireplace - under the assumption that the furnace is a more efficient method of heating than the fireplace.
Looking at the upper portion of the firebox, do you see one or two ports? If there is only one port, then it is definitely a natural vent unit. My valor has two ports, one brings in the combustion air and the other is the exhaust. Try removing some of the front panels, there must be some kind of nameplate on the unit that would be visible.
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dirtmover wrote:
Jan 17th, 2011 5:13 pm
I've got a Vermont Castings fireplace and the cold air most definately falls down the chimney if the pilot light is not lit.

If you're not using it why not get rid of it and block of the chimney?

Do you think it would be more economical and energy efficient to keep the pilot light on if it eliminates the draft?

We don't use it because I believe its less efficient than the furnace, if someone can tell me otherwise, I may consider using it.

Ultimately, I'd love to have a wood burning insert: free wood = free heat, but I don't think we would recoup the cost of the unit in fuel savings.

Removing the unit would leave an ugly bare brick chimney. I guess we could put a screen over it. Any resale value in a 10-20 year old fireplace? I would look into removing the unit myself, something to discuss with the Mrs.
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[OP]
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will888 wrote:
Jan 17th, 2011 8:37 pm
Looking at the upper portion of the firebox, do you see one or two ports? If there is only one port, then it is definitely a natural vent unit. My valor has two ports, one brings in the combustion air and the other is the exhaust. Try removing some of the front panels, there must be some kind of nameplate on the unit that would be visible.

I had the entire front panel off, and the unit was sliding out a bit but would not move anymore until I remove the ducting. No visible model number, just Majestic brand. I could not figure out how to remove the ducting, winter came, so I put everything back together.

It appears to only have one ducting go up the chimney, I cannot see anything else, but there could be something behind and I would not know. My biggest concern is the ducting hovers over the exhaust hole in the furnace, like how an old water heater is. This is the norm for natural vent? Seems inefficient to have a big hole in the house for heat to escape.
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Every indication is you have a natural vent fireplace. As inefficient as it looks, that is how a natural vent unit works - hot air rises. If you home is air tight, having a hole in the chimney by itself does not mean a lot of air movement out the hole. You still need a driving force. Heating the air (fire place on) provides provides driving force to evacuate the combustion byproducts. Sometimes high winds outside can create a negative pressure effect near your chimney. That can also provide a driving force for air movement.
[OP]
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Thanks for the info. I think its still a big hole that would affect the air sealing test of the energy audit. I will attempt to seal it up before my 2nd audit, and decide what to do long term later.
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