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Brewroom Ventilation

I am building a vent hood over my induction brewery in my basement utility room. In the same room I have my furnace and a gas powered hot water heater. There is a 4" duct coming in the provide make up air for the hot water heater. I plan on venting with a 350 cfm fan with 6" ducting. I’m wondering if I should replace the 4" duct with a 6" duct to provide enough make up air. Do we have any HVAC experts out there that can help, also is this safe? :cheers:

If you’re talking about the PVC running from the top of you water heater, it’s probably connected to a small electric motor/fan. That’s a power vent to evacuate the CO out of your home. If it was installed by a licensed plumber it’s likely sized correctly and you really shouldn’t mess with it.

I’m a contractor, not an HVAC expert, but Danny’s right. That vent was probably installed to meet the needs of what is there and no more. And if it IS a power vent and not just a pipe coming through the wall to let in air, you DEFINITELY don’t want to alter that in any way.

The size of the room will be a big factor also. If the room is, say, the size of a small bathroom, you’d probably want to go ahead and add a separate 6" intake vent from the outside. And preferably on the same side of the room as your new vent. If the room is bigger, say, 16’x16’ or so, just leaving the door open to the rest of the basement might work (unless you basement is super airtight.) The goal is to not allow your new vent to draw air (or CO) away from your water heater and furnace. Might even help to put a wall of some sort between your brew area and furnace/water heater area to mitigate any draw the new vent might have on the existing equipment.

Bottom line, if you have any reservations, I would definitely contact someone certified to do gas and vent work. Would be money well spent I think.


Thanks for the responses. Yes the water heater does have a fan powered vent that is pvc. There is also a 4" line that just goes to the outside of the house, and just drops open ended in the middle of the room. I was told this provided make up air since the water heater was pulling air and pushing fumes out. I guess without it may create a vacuum and the fumes would not flow out. I can’t see how it works anyway the vent cap on the exterior will only allow air to escape, not pull air in. I guess I’ll just have to call the plumbers. :cheers:

You said induction… So this is an electric setup?? Why would you need more make up air for an electric setup as there is no combustion??


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My concern is more about the gas water heater. If I have a 400cfm fan drawing air out on a 6" duct am I going to need to put a bigger make up air vent in as well? I’ve read a few things and I’m confused, it might just be easier to call the plumbers that put the water heater in.

Check with your area but 400 CFM typically does not require make up air. Usually it is 401 and up that requires make up air.

Hey there! When I was building a commercial property, then I was also confused with the HVAC system model and installation, then one of my friends recommended me to seek professional help from hvac service old bridge contractor about the planning and designing of HVAC system. I also suggest you to seek professional help in this case.

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