Wood boiler not exchanging heat

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Burnbabe

New Member
Nov 4, 2020
13
Ferrum va
Have a oak tree 150 gal wood boiler been working on for sometime now. I ran about 80ft of 1 pex to the house which is down hill from the stove then back up the hill so total of 160ft. the supply coming in the house goes up about 4ft to my water to water plate exchanger then goes back down 4 ft and over about 20 ft to my furnace with a 15x15 heat exchanger then back the 20ft to the return for the boiler. The pump that came with the boiler is a taco 07 pump. I hooked everything up and purged air out of the lines many of times just making sure there wasn’t anymore air pockets. The pump is circulating water but maybe not fast enough . My stove is set 175 and it barley cuts on . I’m not pulling any warm air through my air exchanger the line coming in on it is hot and the one going out is much cooler but my 10plate water exchanger is working great.

20E0B23F-C93A-4234-B528-C4F141D50C29.jpeg 0FA1651B-FFA9-4AE7-B035-B15FE185D9E2.jpeg
 
When I say my stove is set on 175 I’m not seeing much temperature drop so the stove doesn’t fire up often. I’m not transferring heat somehow it seems? I would love some advice before I go buy another pump
 
I ran about 80ft of 1 pex to the house which is down hill from the stove then back up the hill so total of 160ft.
Is the pipe in the ground insulated ?

Any idea what your inlet and outlet temps are ?
 
Yes they are insulated I put the pipe in the ground say a month ago
No I wish I had somthing handy to measure the temperature. I will have to go get me somthing will a infrared thermometer work I’m open to suggestions ?
 
Yes they are insulated I put the pipe in the ground say a month ago
No I wish I had somthing handy to measure the temperature. I will have to go get me somthing will a infrared thermometer work I’m open to suggestions ?

Insulated how?
 
I’m not seeing much temperature drop so the stove doesn’t fire up often
Insulated how?
Must be insulated well enough if the boiler hardly has a call for heat.
My guess is there is still air in that HX loop...depending on how its routed it can be really hard to get the air pockets out of some spots!
Have pics of that part of the system?
 
I will have to take some in the morning I have a boiler drain in the line I purged air out of then I have another boiler drain right before the return valve on the stove I hooked a water hose up (with the boiler return valve closed and the supply side open with pump off) and pumped water through got some air out earlier. My water is plate is heating great . I need to get something to measure the temperature coming in and out of each heat exchanger.
 
007 is a low head circulator if I recall. Elbows add up pretty quick when it comes to head loss. Try to add up all your 90's and total length of pipe and come up with a head loss calculation. Anything much more than 9-10 and I think you will struggle with that circulator. If it's right on the edge it will make it difficult to purge the air also
 
I agree, the 007 taco is not an ideal circulator, the low head design doesn't work well.
I use a lot of Grundfos 15-58 and occasionally a 2696.
A 10 plate heat exchanger is a bit of a choke point too, a 20 would flow a lot better.
I'd like to see pictures of how the coil is mounted in the ductwork.
 
  • Like
Reactions: sloeffle
Get one of these at each end, easily hooks into your phone to keep tabs on water temps..
 

Attachments

  • A8AAE556-F6A1-4D0B-BDDD-A8A35308A258.jpeg
    A8AAE556-F6A1-4D0B-BDDD-A8A35308A258.jpeg
    110.9 KB · Views: 196
I agree, the 007 taco is not an ideal circulator, the low head design doesn't work well.
I use a lot of Grundfos 15-58 and occasionally a 2696.
A 10 plate heat exchanger is a bit of a choke point too, a 20 would flow a lot better.
I'd like to see pictures of how the coil is mounted in the ductwork.
This was a rough in pic when it was done

i may be able to get a updated picture of the coil later this evening when I get back home. This is what the guymade me from outside heating his name is Edward he bent a couple pieces of metel for me where my plenum is not ideal size
supply for the coil is coming in the bottom port and out of the top tho. The furnace is down I’m my crawl space

2AB89F13-C194-418F-BCF1-47585ABBEBC8.jpeg 5C380BC2-CC5A-464B-A3BD-B6EFB791475C.jpeg 16BD8DBA-CF33-41A2-8785-43E4F1DD8BCD.jpeg
 
Last edited:
What is it called ? Where do I find them at

I get them on Amazon regrettably, they are BBQ sensor probes, there are two probes included, I have one set up for incoming water, the other for outgoing. They offer remote wireless bases, or WiFi enabled that has an app for the phone..
 

Attachments

  • image.jpg
    image.jpg
    152.5 KB · Views: 156
Thanks for all you guys feed back!! I’ve done a lot of searching and trying to make sure the air is out of the lines and nothing was really doing any changes I made sure the pump was actually pushing the water. Today a long day of climbing trees /rigging (tree removal)every piece over a house on the lake I was up there thinking If the pump somehow was clogged or the lines . I got home probably hour ago came out to the stove. I filled The stove up at 7o’clock this morning just got home around 6:30 this evening and the stove had barely burned any wood so for the heck of it I took the pump apart and looked at the cartridge and half of the plastic propeller I was gone somehow? Luckily I had another cartridge the guy gave me when I bought the stove threw it in started it up house is pulling heat Water is hot and the stove recycling like it should. I did buy this would boiler used . I know I’m getting a little age on me now when I’m excited about a woodstove LOL I’ve been working on this project a while glad everything turned out thanks again