# negative pressure problems



## sagstove (Feb 2, 2013)

I have installed two DIRECT VENT gas fireplaces, one upstairs and one downstairs in a new home. The upstairs fireplace runs fine. The fireplace downstairs has had some issues. When I light the fireplace it runs for a few seconds and then the flames ghost out and the unit shuts off. The only way I can keep the unit running is by opening a door to the outside about two inches. Is this caused by negative pressure in the newly constructed house?


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## begreen (Feb 2, 2013)

Sounds like this could be the issue. By opening the window you are providing makeup air. The lower fireplace needs an outside air kit or perhaps the house needs an HRV to improve the lower floor air quality and quantity?

http://en.wikipedia.org/wiki/Heat_recovery_ventilation


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## Heatsource (Feb 2, 2013)

Direct vent units should not be affected by indoor pressure situations, as they are completely sealed systems.

i'd check the vent restrictor settings first, and go from there.

ps, make model of fireplace?
describe the venting set up in detail?


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## DAKSY (Feb 3, 2013)

A1Stoves.com said:


> Direct vent units should not be affected by indoor pressure situations, as they are completely sealed systems.
> 
> i'd check the vent restrictor settings first, and go from there.
> 
> ...


 
What Dave said. The combustion chamber is totally isolated ( or is SUPPOSED to be) from the indoor environment. It's not a pressure problem, it's an oxygen issue.


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## mygasfireplacerepair (Mar 14, 2013)

Was the fireplace installed within its venting limits?  Also check to make sure there is nothing blocking the intake (outer wall of the pipe).  Some units can either be top or rear vent and require removing a metal basket or insulation from the fireplace itself. Is it possible this was not removed?


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