Does the 10-ft rule apply here and/or is there a minimum that a return duct should be from a ventless gas fireplace? Return was in a big open room including the dining room, living room, and kitchen. TIA.
The ‘Rule’ in Minnesota is that Ventless Gas Fireplaces are illegal, so that would make this situation an easy call!
Considering that Ohio is a northern, cold climate state, I’m surprised they do not have similar restrictions as most northern states do.
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There are only a handful of states and municipalities that have banned ventless gas fireplaces citing the same concerns that gas stoves pose. I don’t believe that Ohio is one of them.
I found this interesting in a generic install manual but did not answer your question. Something an inspector may consider. If you lit the fireplace, turned on the ceiling fan and the central heating/cooling system, you might be able to observe a potential problem.
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I do not believe it does. After all the ventless fireplaces is already letting any fuel byproducts into the living space. So I don’t feel it would make much difference pulling this air into the ventilation system.
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I tell my clients to read the operating instructions and to be sure to open windows when operating a ventless fireplace.
The Debate Continues… Are Ventless Fireplaces Safe? (chimneychampions.com)
According to the International Association of Certified Home Inspectors (InterNACHI), “To mitigate CO dangers, manufacturers instruct customers to keep a window open while ventless gas fireplaces are in operation –- advice that is easy to ignore, as an open window allows the entry of cold air, defeating the efforts of the fireplace to warm the living space. Many manufacturers also install an oxygen-detection sensor (ODS) in their ventless fireplaces that will automatically shut down the appliance if oxygen levels in the home become dangerously low. Critics point out that this sensor is typically located at the lower part of the unit near the floor, where it detects cool, fresh, oxygen-filled air and misses hot combustion gasses as they rise and pool toward the ceiling. And if the sensor fails, any CO-producing abnormality experienced by the fireplace will continue unnoticed and potentially harm building occupants.”
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A standard notation I put in all my reports when I come across ventless fireplaces.
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Like @jjonas , I can justify just calling out that the ventless fireplace should be removed because they are not allowed in MN. In your case though, if they are allowed in living areas, I don’t think I’d mention the return duct in my report. There’s maybe some grey area there, but what do you foresee happening differently with the duct removed/blocked? If anything, having it operational might dilute the exhaust gasses and make it less likely there will be a high concentration in any one area?
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On side note, anytime I come across a ventless fireplace, I recommend carbon monoxide detectors in the rooms that they are located in. In a situation like this, probably combo units in bedrooms. CYA even if it may not be a potential of a threat.
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they are quite common here , but tend to cause excessive moisture if not properly sized for the room they are in…
Do either of you guys have the source for this in MN? Citing some code or whatever will make my job easier when I see these units. I assume it applies to ventless propane wall heaters, because I see ventless propane wall heaters in cabins now and then.
I do call them out as a serious CO safety issue and refer clients to the operation instructions in the manufacturer user manual. I usually include a photo of my CO meter with the finding.
They should be banned, IMO.
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We need to stop making stuff up and trying to apply a requirement that does not apply to the situation.
The 10ft Rule is about a furnace. This is not a furnace.
Why is there a 10ft Rule for a furnace?
Not because of that CO Gas you’re probably thinking about. It’s because the return will pull the flame out of the burner compartment into the furnace and house (if the rollout safety does not function).
Will that floor return pull the fire out of the fireplace? If you determined through testing that it is, then you should be jumping up and down, not standing there scratching your head.
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Didn’t make anything up. Was simply asking a question.
Draft hoods also.