Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: MrUPS on January 31, 2013, 06:45:12 PM
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New to the site and just want to say that it seems like there are some great people here and i have really enjoyed looking around.
Now for my situation. I just bought a home that had an old OWS. I bought a new CB 1400 to replace it and have it hooked up but I'm having some problems. The old wood stove was hooked up directly through the boiler system in the house. I wanted to keep the systems separate so I plumed in a shell and tube hx on the return side of the boiler. I want to keep the propane boiler as backup. Do I just need to install a aquastat with high and low cut off on the boiler instead of the one that is on there now that just has the high cut off? If I turn the low setting down below what the OWS water is will that allow the circulating pump on the boiler to run without turning on the propane? Next question. The lines from the house to the OWS are 3/4. (30 or 40 foot run) Is that to small for the system to run efficiently? I only ask because when I had the OWS running the other night I kicked on the boiler in the house to see how hot the water would get in the boiler with the water running through the exchanger and it never got above 140. The OWS is 185. I'm not sure if the 3/4 lines are to small or if the taco 007 that I'm running is to small or if I'm doing something else that I shouldn't be. :bash:
I'm sorry this is so long guys but I'm just having a hard time getting over these couple problems and wanted to give as much info as possible. If you need more info please ask. Thanks in advance for taking the time to help! :thumbup:
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Wow, sounds like numerous issues going on
007's and 3/4" aren't a good combo
Why the shell and tube exchanger?
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Thanks for all the views guys! Scott, the shell and tube is what was sent to me from the dealer. If I could do it over i would go plate style. I wish I'd found this site sooner. I have a taco 009 that just needs a new insert. would that be a better combo or do I need to do something about the 3/4 lines? Any other thoughts?
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Thanks for all the views guys! Scott, the shell and tube is what was sent to me from the dealer. If I could do it over i would go plate style. I wish I'd found this site sooner. I have a taco 009 that just needs a new insert. would that be a better combo or do I need to do something about the 3/4 lines? Any other thoughts?
Got all kinds of thoughts, just kinda thinking about some possibilities
I'd hate to see ur return temps with 007 and a shell exchanger
U ever checked?
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never checked. I'm guessing these shell exchangers are no good?
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i would say the shell and tube exchanger is ok...the pump is undersized (i think)
the 3/4 lines in that short of a distance will work (bigger would have been better)
i would say a pump equivlent to the taco 0014 on the OWB to the shell exchanger, that will take care of any flow problem you have..then add a tee in your return line from the indoor boiler from this tee to your 07 pump and then into the shell exchanger..then out from the shell exchanger to a tee into the "hot out" from the in home boiler and this tee should be before the in home boiler pump suction side
what you want to be doing on the home boiler side of the exchanger is pulling water from the return side of the homes system..pushing it through the shell exchanger where it will be heated and then pushed back into the boiler's hot outlet (or into the homes feed line if the homes pump is running)
charts i find on teh net say you can push 7 toi 8 gpm through 3/4 pex and you want to be near this max so you are delivering the most btu to that shell exchanger as you can.. both pumps must run 24/7 in order to keep your in home boiler water as hot as possable. i would say run your OWB from about 165 or 168 to 178 or 180 and if you need to you might be able to lower your indoor boiler's kick on temp a little (you will need to ask others on that idea, i know nothing of indoor boilers) jsut my thought..the real pros will have better ones likley
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Thanks for the reply willie. I'm going to have to look into the possibly of adding the loop pump i guess. I was hoping that I wouldn't have to run two pumps 24/7.
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Did I miss it or was the size of the heat exchanger mentioned?
Is the return water to the OWB as cold as the indoor boiler? If it is way hotter then the first issue to fix is getting a large enough heat exchanger.
If the return temp is close to that of the indoor boiler then you need to start with a larger pump.
Instead of going with a 0014 you could put another 007 in series and it would be almost the same flow.
If go with a larger pump I would go for something like a Grundfos UPS26-99
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if i read your set up right it appears you have one pump (and i think to small) circulating water from your OWB to the shell exchanger and back to the OWB. you have no pump in the loop of the pipe between the return and feed of your boiler, this would mean you have no flow of the boiler water through this loop unless your indoor pump was running (and this would mean you are using heat) and likely then you would only be pulling part of the water through the exchanger?
by putting a small pump in the exchanger loop of the boiler you would be heating the water in the indoor boiler 24/7 and would always have the indoor water temps as highas your OWB (or close dpending on the exchange rate of your shell exchanger)
RSI is right about the size of the shell exchanger, i was taking for granted it would be of sufficient size as it was supplied by the dealer.... and he may be right on the larger pump for your OWB i was just figuring on about 7 or 8 gmp as that is the recomended max flow for 3/4 pex, perhaps a larger pump would move more water but it will cause more friction as gpm increase. I know only what i read on the pex pipe sites and they say going over the number of gpm in the charts will cause enough friction for premature wearout of the pipes and fittings? true or false i really don't know
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Anytime your going through something like a 60-100 plate or a pool exchanger, I always use at least 1" and often times strongly encourage folks to go with pex al pex for it's larger diameter or 1 1/4" pex. Most plates over 50 are 1 1/4" fittings on them.. I also team that up with a pump that has some good flow numbers... Kinda opposite how this one was done
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bigger linew would sure be better but he has the 3/4 now..a shell and tube exchanger are (i have heard) less restirctive than a plate of the same btu output (?)
before i changed my underground pipe i would try the two pumps and turning the OWB low setting up as high as you could risk..maybe 170 or 175 (?)
i think he said he was only 40 feet away so the head loss shouldn't be too bad...i think he could still get 7 or 8 gpm. it is not the ideal set up but it is there and i would spend a littl etime on it before i gave up and did anything too drastic(?)
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New to the site and just want to say that it seems like there are some great people here and i have really enjoyed looking around.
Now for my situation. I just bought a home that had an old OWS. I bought a new CB 1400 to replace it and have it hooked up but I'm having some problems. The old wood stove was hooked up directly through the boiler system in the house. I wanted to keep the systems separate so I plumed in a shell and tube hx on the return side of the boiler.
Ayuh,.... How Big of a heat exchanger,..?? Btu's,..??
(personally, donno why ya split 'em)
I want to keep the propane boiler as backup. Do I just need to install a aquastat with high and low cut off on the boiler instead of the one that is on there now that just has the high cut off? If I turn the low setting down below what the OWS water is will that allow the circulating pump on the boiler to run without turning on the propane?
This depends on how the burner control aqua-stat controls the burner, pump(pumps?) 'n how the T-stat controls what....
Ya might need to divorce some of the functions to other controls...
Lotsa ways to do it, but We'll have to know what yer startin' with,...
Pictures help,... Alot...
Next question. The lines from the house to the OWS are 3/4. (30 or 40 foot run) Is that to small for the system to run efficiently? I only ask because when I had the OWS running the other night I kicked on the boiler in the house to see how hot the water would get in the boiler with the water running through the exchanger and it never got above 140. The OWS is 185. I'm not sure if the 3/4 lines are to small or if the taco 007 that I'm running is to small or if I'm doing something else that I shouldn't be. :bash:
I'm sorry this is so long guys but I'm just having a hard time getting over these couple problems and wanted to give as much info as possible. If you need more info please ask. Thanks in advance for taking the time to help! :thumbup:
That's another point,... pictures will help, How do ya have this thing plumbed up,..??
How are ya move the heat,..?? zone pumps, or zone valves,..??
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Going with BTU ratings on the heat exchangers probably won't be of much use if it was a pool heat exchanger. The btu rating on a pool heat exchanger will be for around 70 degree water entering it. (maybe even lower)
On your indoor boiler you are only raising the temp a little under load.
A tube in shell heat exchanger large enough would probably be around 5 or 6 inches in diameter and 2 or 3 feet long.
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I think we can stack this whole scenario up as why a dealer is important, or a good dealer I should say
System design is nothing short of essential
The way it is now, it's a patch job to get it working alright, it would have been cheaper and much better to do it right the first time
Once we know more, we can help more
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My dealer or ex dealer sold me 1 1/4'' pex for my 5036. The fitting on the boiler is 3/4''.Im not sure if im getting the fill effect of the 1 1/4'' pex or not but it seems to me that I could have saved money by running 1'' or 3/4'' pex.
That dealer was in N.H. in Colebrook. Has been useless.
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Sorry for the delay guys. I was trying to get some pictures on last night but that just wasnt in the cards. The shipping business is relentless. I did how ever make a disappointing discovery. The boiler system is set up to pull the water through the system SO....I have the hx plumed into the hot side coming out of the boiler, not the cold(return) :bash:
I did measure the hx its 48" x 3". I had been happen with my dealer up until last night when I got the bill for my hx. I had called 3 weeks ago and told them what I was doing and that I needed a hx for my system. Was told that was no problem and they would ship on out to me. I get the bill yesterday and its $760! That included shipping but holy smokes! Does that sound like a fair price to you guys selling this stuff? I will work more on some pictures tonight, thanks for the continued help here guys :thumbup:
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My dealer or ex dealer sold me 1 1/4'' pex for my 5036. The fitting on the boiler is 3/4''.Im not sure if im getting the fill effect of the 1 1/4'' pex or not but it seems to me that I could have saved money by running 1'' or 3/4'' pex.
That dealer was in N.H. in Colebrook. Has been useless.
probably did you a favor
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My dealer or ex dealer sold me 1 1/4'' pex for my 5036. The fitting on the boiler is 3/4''.Im not sure if im getting the fill effect of the 1 1/4'' pex or not but it seems to me that I could have saved money by running 1'' or 3/4'' pex.
That dealer was in N.H. in Colebrook. Has been useless.
How long is it? The fitting at the boiler has little to do with the required pex size.
The larger pex will save money in the long run if you have a properly sized pump.
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Sorry for the delay guys. I was trying to get some pictures on last night but that just wasnt in the cards. The shipping business is relentless. I did how ever make a disappointing discovery. The boiler system is set up to pull the water through the system SO....I have the hx plumed into the hot side coming out of the boiler, not the cold(return) :bash:
I did measure the hx its 48" x 3". I had been happen with my dealer up until last night when I got the bill for my hx. I had called 3 weeks ago and told them what I was doing and that I needed a hx for my system. Was told that was no problem and they would ship on out to me. I get the bill yesterday and its $760! That included shipping but holy smokes! Does that sound like a fair price to you guys selling this stuff? I will work more on some pictures tonight, thanks for the continued help here guys :thumbup:
Considering that a plate heat exchanger would have been about $350 for a 60 plate I would say that is a lot.
Is it stainless steel or copper tubes inside it?
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U got hosed, wrong heat exchanger and double the cost to what you needed
It's crazy that he thought you needed one of those
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How long is it? The fitting at the boiler has little to do with the required pex size.
The larger pex will save money in the long run if you have a properly sized pump.
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The run is about 50' and the pump is a Grundfos 3 speed.I think on par with a 007 taco. And I have been runing the pump at the slowest setting.
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It's probably a 15-58
It's more pump than an 007 but i would def be running it on high, everything will work better, stove better protected and all that for an extra buck or two of electric
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What would that protect the stove from?
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Higher flow rates reduce delta t, being the difference between supply and return temps
If the delta t is to large you'll have condensation in the firebox, that leads to early death. That's why central boiler now requires boiler protection systems as well as empyre. They use thermostatic valves to make sure return temps are over 140-150 at all times
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Hey, thanks alot.
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Sorry for the delay guys. I was trying to get some pictures on last night but that just wasnt in the cards. The shipping business is relentless. I did how ever make a disappointing discovery. The boiler system is set up to pull the water through the system SO....I have the hx plumed into the hot side coming out of the boiler, not the cold(return) :bash:
I did measure the hx its 48" x 3". I had been happen with my dealer up until last night when I got the bill for my hx. I had called 3 weeks ago and told them what I was doing and that I needed a hx for my system. Was told that was no problem and they would ship on out to me. I get the bill yesterday and its $760! That included shipping but holy smokes! Does that sound like a fair price to you guys selling this stuff? I will work more on some pictures tonight, thanks for the continued help here guys :thumbup:
Ayuh,... Dependin' on how the system it plumbed up, that may not be that bad,...
If yer tryin' to move the heat to the house, it don't matter so much...
If yer tryin' to use the gas boiler as the distribution block, Ya, that's Bad, as the hot water would need to go through the house 1st, loosin' all it's heat...
I still say, if the OWboiler is capable of bein' a pressure boiler, I'd go back to the way ya found it...
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How long is it? The fitting at the boiler has little to do with the required pex size.
The larger pex will save money in the long run if you have a properly sized pump.
The run is about 50' and the pump is a Grundfos 3 speed.I think on par with a 007 taco. And I have been runing the pump at the slowest setting.
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If you had 1" pex then the pump would have to be on high to be close to the same flow rate. If 3/4" was used then a larger pump probably would have been needed.
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Just going by measurements of HX is guesswork, need specs, is it like this? Just guessing by cost and dimension.
http://www.altheatsupply.com/shop-by-needs/heat-exchanger/pool-heat-exchangers/stainless-steal-tube-and-shell-heat-exchanger-350k-btu.html (http://www.altheatsupply.com/shop-by-needs/heat-exchanger/pool-heat-exchangers/stainless-steal-tube-and-shell-heat-exchanger-350k-btu.html)
It looks kinda like that. Its copper though, inner piping and outer. Has female bungs on the top, bottom, and two on the side, one towards the top and the other towards the bottom. I will work on getting up some pictures tonight so you guys can see what I'm dealing with. Im still beside myself at what I was charged buy the dealer for my hx. Thanks again for the continued help.
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Oh bondo, I don't think I can run it as a pressurized OWB. Thanks for the thought though. :thumbup:
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Oh bondo, I don't think I can run it as a pressurized OWB. Thanks for the thought though. :thumbup:
Most def not, they are open systems
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Just going by measurements of HX is guesswork, need specs, is it like this? Just guessing by cost and dimension.
http://www.altheatsupply.com/shop-by-needs/heat-exchanger/pool-heat-exchangers/stainless-steal-tube-and-shell-heat-exchanger-350k-btu.html (http://www.altheatsupply.com/shop-by-needs/heat-exchanger/pool-heat-exchangers/stainless-steal-tube-and-shell-heat-exchanger-350k-btu.html)
It looks kinda like that. Its copper though, inner piping and outer. Has female bungs on the top, bottom, and two on the side, one towards the top and the other towards the bottom. I will work on getting up some pictures tonight so you guys can see what I'm dealing with. Im still beside myself at what I was charged buy the dealer for my hx. Thanks again for the continued help.
The size and being copper explains why it cost so much. I wonder if he had a reason to sell that instead of a plate.
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yeah I'm wondering the same thing. I could have gotten one heck of a plate style hx for that money ::) I'm gonna call on Monday and share my "concern" with there choice and price!
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Ok, So I finally got a pic. If I understand correctly. In order to fix my multiple problems, what I need is. A larger pump at the OWB, a circulating loop with a pump at the boiler and I need to get the hx on the cold side instead of the hot side :-[ . Does it sound like I'm on the right track here? Do you guys see anything in the pic that looks off? I called today about the price of the hx and I was told "thats the price" I asked why they use that style and not a plate style. Was told that the plate style require more maintenance and cleaning. Not sure I'm buying that one but it is what it is and I'm stuck with what I got. LESSON LEARNED! Thanks again for all the help guys. I really appreciate it.
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What size are the internal tubes in the heat exchanger?
Sound like a good plan you have. Should make a huge difference.
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Can someone explain to me where this extra pump is going and what it's going to be doing? I'm confused
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Can someone explain to me where this extra pump is going and what it's going to be doing? I'm confused
I think he plans on having it circulate the water from the indoor boiler through heat exchanger to keep the indoor boiler hot. Otherwise it will cool down when the house isn't calling for heat. Then when the house does call for heat it would start pumping the cold water out of the indoor boiler through the house as it re-heats the boiler.
It might work fairly well without the pump but it would depend on how much the indoor boiler cools down when the indoor pumps are off.
If adding the extra pump, I would control it with an aquastat. No reason to have it run 24/7.
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Yea a ranco would work well on that, I assumed the other boiler already had a pump running through it all the time. It would def work much much better circulating that water through it
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Scott this is my plan with the circulating pump. http://www.centralboiler.com/Tech/C220.pdf (http://www.centralboiler.com/Tech/C220.pdf) I'm hoping that by circulating the water through the hx and into the boiler 24/7 than when the house calls for heat the boiler will just kick on the house circulating pump and not fire the propane. I'm not sure what a ranco is though....is that a type of pump? I have have a taco 007 on the OWS now, I now know that is to small so I could use that as the pump or I have two Groundfos UPS 15 58 fc. I could use one of those??
RSI I'm not sure how using the aquastat is going to work? I'm not doubting your suggestion. I just need it explained to me. :-[ Wouldn't the aquastat let the water in the boiler cool down thus kicking on the propane to heat the water in the boiler? Also I didn't look real close at the tubes in the hx but I would say they are about the size of a pencil and there where 10 or so of them in there.
intheoaks I dont know enough about this stuff to say for sure whats better or worse but for the money I payed for this over sized piece of copper it had better work! :o If I could do it over I would have got a plate style but were past that...
You guys are awesome. Thanks again :thumbup:
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You could use the 007 to circulate through the plate, a ranco is an aquastat. It's basically a switch control by temp, for example if your boiler temp was 175, you could set it so that "that" particular pump would t run til it cooled down to a certain degree.
One of those 15-58 would be better on the stove than the 007 but still a bit small i think
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I was thinking the same thing about the 15-58. I think I might put it on the OWS just to see how much difference it makes. I should run it on high I assume? Still have the other "big" problems to fix too. I'll have to look into the aquastat. I think I understand whats going on there but I wouldn't know were to hook up the thermostat wires (i'm assuming thats what gets hooked to it) My very steep learning curve continues. haha.
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The ranco would or could use it as a strap on, sensor would strap onto a pipe. The wires from the pump could go into the ranco, to be powered on and off
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I'm not sure how using the aquastat is going to work? I'm not doubting your suggestion. I just need it explained to me. Wouldn't the aquastat let the water in the boiler cool down thus kicking on the propane to heat the water in the boiler?
Ayuh,.... If there's another port in the propane boiler, you could put an aqua-stat in it to control the H/E pump...
The pump would be the only thing hooked to the aqua-stat...
When the boiler drops below yer set-point, the pump would come on, reheatin' the boiler to the high set-point, then shut off, til the propane boiler calls for heat again...
The propane fire controls will need to be set lower, or by-passed...