Need help getting this to work
The house I just bought has a basement that is uninsulated. There is a fireplace down there that I would like to try to use to provide some heat the the upstairs of the house. There is a stairwell near the wood burner and I can get the basement up to 80 degrees, but I can't get the heat to circulate upstairs. Eventually, I'm going to put some cold-air return registers in the far corner of the upstairs to help to circulate the air, but I don't want to do that until I get the exterior basement walls insulated so I'm not losing alot of my heat through the cinder blocks.
So in the near-term, I built this sheet-metal shroud to retain the heat that is coming off of the firebox. I then boxed the end off with a round 6" aluminum duct and then ran the duct in the rafters to a register that I cut in the floor upstairs. You can see the shroud and ducting here:
Some heat trickled up through the ducting, but not enough to make a difference in the temperature upstairs. Additionally, the shroud was getting very hot which means there was a lot more heat that could be harvested. So I bought a 300cfm inline fan and put it on the "downstream" side of the shroud blowing towards the register. The inlet side was drawing the hot air from under the shroud and pushing it through the ducting to the upstairs. I drew a picture so you can see what I'm talking about. (the fan is depicted in green):
This worked GREAT as I was able to feel heat blowing like crazy out of the register and I was able to get the upstairs up to 77 degrees if I really burned hot in the fireplace. I ran into a problem however in that the air on the downstream side of the shroud must have gotten too hot for the fan, and it tripped the thermal protector switch and killed the motor.
So I purchased another inline fan (this one 400cfm) and figured I would put it on the upstream side of the shroud and have the fan pull cold air from the basement, and push it through the shroud and up the ducting. You can see a picture of this here:
I bought the bigger fan because I thought that the extra "oomph" it provided would be enough to push enough volume of air through the open space of the shroud and still have decent velocity coming out of the register. That didn't seem to work though because the shroud isn't completely sealed and it was barely moving any air out of the register so that isn't going to work for me.
So, I need to somehow have the fan not be exposed to the heat on the downstream side of the shroud, but still be effective at moving the hot air from under the shroud into the ducting. I am thinking about putting a "T" on the downstream side of the shroud and connecting the fan to push straight up the ducting and having the 90-degree opening attached to the shroud to hopefully have the airflow create a vacuum that would suck the hot air into the ducting with the air that will be moving from the fan running. What do you guys think of that approach? Here is an example of what I'm talking about:
If the air being blown by the fan wanted to back-feed into the shroud instead of going up the ducting, I was thinking about fabricating a small piece of metal that would block the opening back into the shroud but would still allow air from the shroud to enter the duct, kind of like this (yellow would be the diverter):
So that's where I'm at, and I'm open to any/all suggestions for how I can get this to work like it did when I had the fan directly on the downstream side of the fan, but I can't have the fan exposed to that much heat. Thanks a lot everyone!
Make sure you've paid up your life and fire insurance
Keep the fire inside the fireplace.
Illegal & dangerous! You won't find anyone around here willing to help you on this. Trying to duct an appliance not specifically designed for it can be deadly for a variety of reasons. Is it worth losing your house or your life to save a couple of bucks?
BTW, don't bother with the fire insurance. As soon as an inspector/adjuster sees that it will be cancelled immediately.
Where are you? Are you done yet? I got ONE more call for you.....
I just showed my better half the pictures and shaking our heads wondering why would someone do this. Buddy if you have kids be responsible and shut this system down and never put it on, call a fireplace shop and save your family from death....
^^^ what he said, flue gasses aren't the best thing to breathe!
Originally Posted by gasguy
OK then. I apologize for asking.
The shroud is collecting heat from a sealed unit and diverting it to a register upstairs that has a CO detector located adjacent to it. There is no exposure to spark or open flames. Again, sorry.
You're messing with a lot more than what you've already posted. As mentioned ^ you are risking your life and property, I doubt your insurance will cover anything once they see your rigged up fireplace.
Originally Posted by xpauliber
If you consider yourself to be responsible, you'll undue everything you've done and hire a professional to address your needs.
These responses are blunt because of how dangerous the situation is.
To the OP: you yourself described how hot the duct got. Ok-how much is too much? Clearance to combustibles? What is the maximum service rating for that ducting? Is it listed for that application? Where does the mfr. show this hood in their listed instructions for heat capture?
A carbon monoxide alarm alerts just prior to CO death--it does nothing to protect against CO poisoning and they are very unreliable. Do you have a dual sensor smoke and fire alarm on each floor and in both the stove room and the room where this heart discharges and are those alarms regularly maintained and less than 10 yrs old? What safeguards are there to protect against thermal burns from this duct or the discharge? What sort of grille or register prevents entry of items down this hot duct?
Is that stove listed to UL 1482? Does it have a full length chimney liner listed to UL 1777 with the maximum insulation required for a 2,100F rating? You do not have a min. 16" noncombustible hearth extension visible in front of the stove.
Keep the fire inside the fireplace.
I appreciate the input although I think it could have been given in a much less derogatory, non-condescending tone but online forums are notorious for that type of behavior so I shouldn't be surprised. I'm not some demented person that has no concern about the well-being of his family or home. I'm just a young guy with some ambition who just purchased his first home and was trying to find a solution to a problem. After the valuable input that I received from the experts on this site, I've decided to scrap the whole plan and try to force heat upstairs by putting some cold-air returns from the upstairs down into the basement and try to get some air circulating in that fashion irregardless of not having the exterior walls insulated.
Thank you all again. I truly do appreciate it. God Bless.
Moderator: If possible, please delete my account from the hvac-talk forums. Thank you.
Originally Posted by xpauliber
The intent of our posts was to inform you of the dangers, not to demean you in any way. Simply put you do not have the knowledge and experience to perform the task you are trying to perform. Adding returns in the basement COULD cause the fireplace to backdraft by creating a negative pressure in that zone in your house. Please contact a professional for safties sake. God Bless and be safe.
I would like say the op was right in his assessment of the replies, they were degrading and over the top. with replies like you all gave there is little chance in them doing the right thing(we got lucky with this guy). You guys had the right idea in informing him it is highly dangerous situation, but you didn't need to insult him. Some people who didn't grow up around hearth products don't realize the dangers of how heat can saturate through materials and cause fire hazards. I don't want to sound like your mother but you aren't helping when you just insult.
Edit: To the OP if your are still around, they do make registers with fans in them, so after removing the ducting you could try that.
The only insult I saw was from isuredo. Not even a terrible one but okay, it was an insult.
Originally Posted by darthvader
Everything else was blunt but reasonable and important for him to understand why he should not be experimenting.
In the next post he made a decision to remove his contraption and open up cold returns in the basement, again without consulting a professional, which can be equally as dangerous.
DIY can be tragic when done without the proper education.
I'd rather hurt someones feelings than not get that message across.