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Natural flow gas furnace in the same room as the return air vent for the air conditioner

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We are looking to rent a house. while we were looking at the house the owners pointed out that they have just had a new central airconditioning installed in the house. I noticed that they had a natural flow gas furnace in the same room as the return air vent for the air conditioner. my concern is this: Will the return cause a vacume in the fluepipe and suck the exaust gases into the house instead of letting the flow naturally out the pipe? ifso how can this problem be fixed?
asked in Heating and AC by darekrudy (21,730 points)
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1 Answer

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Hi Gerald,
Go over this article – http://checkthishouse.com/14/air-return-in-forced-air-heating-ac-systems.html and if that doesn’t answer your questions please let me know. If this room that contains the furnace (or any other gas burning appliances) is large enough or properly ventilated to provide sufficient amount of combustion air (http://checkthishouse.com/3518/chicago-condo-inspection-combustion-air-requirements.html – it applies to all places, not only the Chicago condo) for the burning process and if the return is not less than 10' from the combustion chamber, everything should be fine.
I’m assuming that this AC system is using the same air ducts as the heating system. If it’s less than 10' between the combustion chamber – return, and / or there’s not enough combustion air in this room you’d need to hire an HVAC professional. It’s difficult for me to give you some kind of a solution because I can’t see this area, furnace installation, and I don’t have its technical data. You’d have to provide a few pictures and a lot of details that would be critical in answering it.
Start from reading those two articles, maybe they will provide enough help. Let me know.
answered by darekrudy (21,730 points)