Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: right2bear on January 11, 2015, 08:38:20 AM
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Have you temped your baseboards to see what kind of heat your getting?
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What is your water temp coming in the house? That's alot of 90s, I think they say 1-90 equals ten feet of pipe. Is everything run through your sidearm?
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Check water temperature leaving the boiler and water temperature entering the house. Also check water temperature entering the water/water HX and water temperature exiting it too.
Your water/water HX is rated at 300,000 BTU and you've already stated that you can only get half of that amount with your maximum flow. It's also possible that you won't be able to achieve 15 GPM through 1" PEX. I don't remember the numbers on flow vs size, but 15 GPM seems high for 1" PEX. I'm sure someone will chime in on that.
Another possible cause is that you're heating your domestic water prior to heating your house and that might be sucking away too much heat from the wood boiler's water to leave you enough to heat your house. If it's not too difficult, I'd reverse the order and see what your system is capable of at that point. It looks like you used a good deal of shark bite fittings, so switching things around should be simple.
Also, verify that your water/water HX isn't plugged up with something like a chunk of plastic or anything else during installation.
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3/4 copper can move about 7 gpm and with the grucfos pump you mention it likely is
if I am right and see 3/4 pex in the home that is only rated at about 4.6 gpm and the 1 pex is rated at 7.5
with the mix of 1 and 3/4 (if I am seeing what I think I am seeing) and your Honeywell circulator, I would put your OWB flow at about 3 to 3 1/2 gpm
as suggested you need to verify temps at all 4 ports on the water to water exchanger when the house is using heat.
you may be able to (again if I am seeing right) change all piping to 1 inch pex indoors (or 3/4 copper) and get away with the pump you have and get your delivery to 7 gpm. that will be nowhere near what yourplate exchanger is capable of but I don't think you need near that to heat your home
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guess my eyes are getting bad..ok so if you have all 1 inch pex we can say your Honeywell may be doing 6 gpm
now you say you have mostly 1 inch or larger copper until it splits (I take it that means at least 2 lines if not more) to feed your baseboards
so 1 1/4 inch copper can move 16 gpm 1 inch can move 10 and each 3/4 line can move 6.5
you still need to verify all temps at all ports when using heat to get an idea of what is happening
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This shouldn't be hard to figure out. Yes first off we will need the temperature readings into and leaving the flat plate on the owb side and also both readings for the indoor furnace side. Next how is the indoor boiler side plumbed into the system? Does it flow through the flat plate on the way back from the house before it enters the boiler or does it flow through the flat plate when it leaves the boiler to head to the zones of the house? What does the temp gauge read on the house boiler? Have you tried running the indoor house boiler and making sure that everything heats right up in the house like it should?
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I think you have a flow problem somewhere through your zones. Probably a big air bubble somewhere that was introduced into the system when you opened the system up to add the flat plate. I would start off by bleeding all of your bleeders in your system. Then I would take temp measurements on each zone leaving to head to the slant fin and temp when it returns.
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I have re-read your original post and would like to point out that there is a huge btu difference is what you may be deliviering to your rooms.....
you stated the boiler (indoor boiler) was set to 200 degrees...now you show your water temp leaving the plate exchanger going to the baseboards is now 176
lets say with the boiler at 200 you are averageing ten less, 190 and lest say now you are averaging 170
now
3/4 inch single tube slant fin will give off about 675 btu per per foot at 190 degrees
the same slant fin will only give off about 535 btu per foot per hour at 170 degrees
so if you have an 8 foot fin tube you are now putting out over 1000 btu per hour less
this could have quite an impact on keeping your house warm at times
if you measure your home boiler side of the water to water heat exchanger and verify that your delta is less than 20 degrees you could add more baseboard to get more btu in the home
if your delta is less than 20 you need to get more water from the OWB
most boilers in the home run about 180, when you said yours was at 200...that may point to a problem of not enough baseboards a while back and to compensate the boiler temp was increased?
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aslo in your original post you say when you used propane you could heat the house to any temp you liked....so, go look at the propane burner and find out how many btu per hour output it is rated at and you will have an idea of how many you may be asking of your OWB?
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I think you bring up some excellent points as well. You certainly may have a lack of slant fin in the house that they were compensating for by bumping the system to 200 degrees. I missed that you said you had bumped the owb to 200 degrees. Looks like you are losing 15 degrees from the boiler to the house! That is wayyyyyyy much. Second thing is you should be able to match the temp or close to it on the flat plate but looks like it's 10 degrees under the owb which I am not sure why that isn't bringing the water all the way up.
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Sounds like things are getting better. I would certainly say that you don't have enough slant fin because if the fact that you need to run iit at 200. Second thing is that you will probably be able to make it through this season with whatever pipe that you put in the ground but you will need to fix/replace it next season. 7 degree loss from the boiler to the house and 7 back to the boiler is Huge. Before moving that water slower you lost 30 degrees just pumping the loop!!!!! You are going to go through twice as much wood and have short burn times if those temps are accurate. 2 degrees each way for every 100 ft is about max on the acceptable level.
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If I understand it correctly, his first thermometer inside of the house is just before the flatplate exchanger, which is after his sidearm exchanger. So he's losing 7 degrees total with the underground lines and the sidearm and not just 7 degrees in the lines underground.
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You are correct but I bet he loses only 1-2 degrees through the sidearm when the tank is cold. When it's hot he will lose very little. He was losing 15 degrees moving the water slower through the system.
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Gotcha. That makes sense. Perhaps he can give us temps prior to and after the sidearm to verify.
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From what I can see from the one pic there is at least one elbow you can eliminate from the system. Turn the pipe from the sidearm to the plate exchanger 45 degrees and remove the bottom elbow.
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agreed,theres alot of 90s there
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193 entering exchanger from OWB after passing though side arm (good)
189 going to fin fans from exchanger (good)
160 to 165 returning from fin fans to exchanger to be reheated (acceptable)
all important temp not shown....return temps going back to OWB. this number will tell if you are moving more water than the indoor boiler and if you have room to add more baseboard if you think you need it
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So I'm curious have u figured out the problem yet?
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Me too. This inspired me to look at my system and I can see where some improvements can be made this off season.