Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: Maxnchej on November 19, 2014, 05:10:43 PM
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I have a two story home, 11 years old so it is insulated well. Main floor is 1300 SQ feet, up stairs is 1100 sq feet and basement is 1300 sq feet and is unfinished and most heat vents are off. Since we have started using our new OWB the main floor of the house is very warm and upstairs is cooler. Something we didn't notice before when we heated with propane. Have others experienced this?
The vents on the main floor of the house feel warm when the furnace is not running, I figured than the heat from the air exchanger is raising and keeping the main floor warmer causing the thermostat to turn the furnace fan on less, anyone have thoughts?
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I would think heat would come off the exchanger even when the fan is off. I have not personally noticed this for my house, but it certainly works this way for the shop. I gain at least 10 degrees in temperature with the fan off and heat radiating from the HX. Only when I am in there working do I turn the fan on and crank the heat up.
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I had a neighbor that had a fireplace insert and his upstairs stayed cold. He put in a open floor vent in the upstairs just above the insert and it evened out the temps from upstairs to downstairs. This may work for you. You may could even put a fan with a thermostat in it.
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Circulation between floors is great BUT, please allow me to enlighten you a bit, vents between floors are illegal because in the event of a fire, they become a chimney and allow the fire to spread much faster. I know, there are hundreds of thousands of grandfathered systems like this BUT, if your house burns and the insurance company determines that you added that vent, don't expect that they will pay off the claim. NFPA-211
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Why not just turn the furnace fan all the time, to help keep the air moving thru out the house??
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I wouldnt be able to say for sure but it sounds like a balance issue, heat coming from the heat exchanger is probably a lot warmer than that if the propane was supplying the heat and so your thermostat is being satisfied quicker than before, what I'd do is play with the registers and close them halfway or some of them halfway and leave the upstair registers open. Cold spots in a house with a forced air furnace is almost always a balance issue weather it be a poorly designed system or HVAC guys doing hack work (example: lots of flex round pipe)
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Circulation between floors is great BUT, please allow me to enlighten you a bit, vents between floors are illegal because in the event of a fire, they become a chimney and allow the fire to spread much faster. I know, there are hundreds of thousands of grandfathered systems like this BUT, if your house burns and the insurance company determines that you added that vent, don't expect that they will pay off the claim. NFPA-211
Thanks SlimJim, I agree and this is something that I will not being doing. There is no way that I'm going to risk an insurance issue to save a little on heat.
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Why not just turn the furnace fan all the time, to help keep the air moving thru out the house??
Thanks LittleJohn,
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Why not just turn the furnace fan all the time, to help keep the air moving thru out the house??
Thanks, but I don't want to run it all of the time, house would be to hot and it would burn to much hydro, thanks for the input.
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I wouldnt be able to say for sure but it sounds like a balance issue, heat coming from the heat exchanger is probably a lot warmer than that if the propane was supplying the heat and so your thermostat is being satisfied quicker than before, what I'd do is play with the registers and close them halfway or some of them halfway and leave the upstair registers open. Cold spots in a house with a forced air furnace is almost always a balance issue weather it be a poorly designed system or HVAC guys doing hack work (example: lots of flex round pipe)
Thanks for the tip, I think I'm going to give that a try. I know when I build the house they had a hard time since we are running max spans on the Joice and they are running multiple directions.
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We simply close either the dampers or the vents on the main floor to force more heat upstairs.
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I'm a little surprised nobody has mentioned this,...........but as I read it, it sounds like your HX is hot all the time?? That would cause a constant radiation of heat to the main floor for sure. I've got a total of 6 water to air HX's with blowers set up. Each of them are set up with a 3-way zone valve at the HX to stop the flow of hot water to the HX when there is no call for heat. At the time I set it up I didn't know any better. My dealer suggested I set it up with the zone valve. Said it would save wood. The first night I lit the furnace (back in 2008) I did not have the wiring finished in the house so I left the zone valve open to allow the hot water to flow. With temps outside in the 40's overnight, my house was over 80 just from the radiant heat that night. I'd never run without the 3-way zone valve. I would think if you installed a zone valve, the main floor would be allowed to cool at the same rate or closer rate to the upstairs so as to maintain a more consistent temperature throughout the house.
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What kind of flow can you expect thru a zone valve?
Can't remember the project I was woking on, but had a zone valve with one inch sweat fittings, the ports in it weren't any bigger than the one that was 1/2" sweat fittings.
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Mlappin and Downeast , both great points, I had missed that as well, this is another reason I like a primary secondary piping system as water only flows from the main loop to the heat exchanger on a call for heat.
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I don't have any way of knowing what the flow rate is. My math skills are not that good. But, I've been running this way since 2008. My house is never as comfortable while running the oil burner. First off, it's a more consistent heat temp coming out the vents. Oil burners get very hot so you get hotter air coming out at first. Then you get the cool down cycles. The air temp always seems to be changing. They way I am set up with the 1" zone valve and 1" Pex fed by 009 Taco pump is much more consistent. The zone valve is wired in between the thermostat and the fan center relay switch. The way it works is good in that when the thermostat calls for heat it opens the valve first for a few seconds to allow the hot water to preheat the HX before engaging the blower. So the only cool air I get is just what's in the pipes on startup.
For reference also, my other 5 HXs are in greenhouses. Very high demand for heat in a greenhouse (oh, I do run 2 OWBs during the greenhouse season). All of those heat exchangers are fed by 007 pumps using 3/4" pex and 3/4" zone valves. All 6 HXs are rated at approx. 140k btu (roughly 19"x20" I think)