Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: muffin on September 22, 2011, 10:33:17 AM
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Just fired up my CB 6048 for the first time. I installed a temperature sensor on the return line for fun. I have the thermostatic valve installed in the main lines, so I guess the return can never really get below 150 F. With nothing running, what would be expected or normal for the return temperature? Is there a good way to read the temperature at locations along the pex/fittings to find heat loss problems?
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Heat loss in the house will be different for every house. It just depends on how the pipes are run, etc.
If it isn't making any part of your house too hot I wouldn't worry about it. It is not wasting any heat if it is inside the house and actually may save a little since it might keep the blower from running quite as much.
If a area is getting warmer than you want, just put pipe insulation on the pipes.
The most loss will be at the heat exchangers. There will be some thermal convection going on. It is usually only a problem when it is warm outside and the house gets hotter than the thermostat is set.
The only way to avoid this is with a zone valve to bypass the heat exchanger when it isn't needed.
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muffin, I am interested in this also. What type of temp sensor did you install?
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i agree with RSi. heat loss from a pipe in the house should not really be counted. anything lost to the house does not need to be generated by any of your "appliances" unless it is making an area of your home "too hot" and not controlable i would not worry about it. to get your true heat loss you would need to just measure your temp difference at the point it leaves your OWB and where it enters your home. If your burried pipes are below the frost line you will know your heat loss now as the ground temp below frost line changes very little. if your pipes are not below the frost line then your heat loss between the OWB and the home will be forever changing. heat loss will change with with the ground tempature.
there are many things that contribute to heat loss but in teh world of OWB i think most of those are controlled all but one..ground temps. we have (basically) constant supply flow (GPM) and constant pipe temps. the only thing we don't control is the earths temp or water volume (both of which can change heat loss data) most (i think) of the major underground pipe suppliers for OWB will tell you anywhere from less than one degree loss up to about 3 degrees loss per 100 feet of pipe
another thing to consider is if you don't burry your pipe below frost you might, by leaving it laying on the surface (if out of the wind) actually have less heat loss than in the ground above the frost line.
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muffin, I am interested in this also. What type of temp sensor did you install?
It is just a simple gage I got with all my other pex stuff:
http://www.outdoorfurnacesupply.com/gauges/2-1-2-tridicator-1-4-cbm.html (http://www.outdoorfurnacesupply.com/gauges/2-1-2-tridicator-1-4-cbm.html)