greenwood boiler

[djblech]

I just fired my greenwood boiler last night for the first time. ( I waited 6 months for the installation kit that included a new and improved manifold) I am running about a 100 ft loop from the furnace to a heat exchanger. From the heat exchanger to my propane boiler is a short loop. My question is this; Everytime my zones call for heat my propane boiler kicks in. I am wondering if I can wire the pump on the propane boiler to run constantly, this will circulate the hot water in the short loop so that the propane boiler won't have to kick in.

 

[2.beans]

can you unplug the propane burner so it cant come on instead of having a pump run all the time?

 

[djblech]

I think my zone valves are all wired in with the boiler. I may need to just disconnect just the propane boiler, but I still want it on line for back-up. I thought of putting an aquastat on the propane boiler that would have it kick in if the temp falls below say 140. I'm not sure how that would work. I had hoped that the hot water from the greenwood would keep the propane from coming on, but that is not working. The main thing I'm woried about is the thermal spike because the propane is back heating the greenwood through the heat exchanger.
Thanks for any suggestions.
djblech

 

[sled_mack]

Check the propane boiler again. My oil boiler has an aquastat that controls the water temp of the boiler. In my original setup, I just adjusted that down to 140 so it would pick up if the wood boiler was not keeping up to that temp. Worst case, you may get a short burn till the loop gets hot, but if it is running periodically, the loop shouldn't cool off that fast.

 

[Hydronics]

Tee into the gas boiler between the zone(s) circulator and the gas boiler, assuming the circ. is on the supply: this where the wood boiler supply should tie in.
Tee in on the gas boiler return and tie the wood return in here.
Flow will be in reverse through gas boiler when no zones are calling. This will maintain temp. for tankless domestic coil.
Install a circ. on the wood boiler return, control it with an aquastat in wood boiler or clamped to supply that makes contact on rise.
Reset gas boiler control to on @ lower temp. for backup.

 

[djblech]

I am putting a call in to my plumber that helped me do the install. If I can turn down the kick-in for the gas boiler that should do the trick. Thanks Sled Mack. Hydronics, I have just what you described in a short loop, no more than 10 ft, to my heat exchanger, using the circulator in the gas boiler to circulate. I put 3 ball valves in 1 on each line and 1 in between so it has to circulate. The gas boiler temp must be set higher than the wood boiler. I am getting 175 -190 on the temp gauges at the wood boiler. I don,t think it is cycling (draft open) long enough for a good burn. Since my return is coming back hot, I don,t think I'm using all the heat potential that my wood boiler is creating. Once I get the gas to quite kicking in, the wood should run even better. Greenwood said I would get condensate out of the bottom of the boiler at start-up, this has been dripping for 24 hours. Is that ok?

Thanks,
djblech

stihl 170 + 360
kioti dk45 and farmi winch
120 acres woods 3 miles from home
Greenwood 100 in garage 50' from house (to end my propane addiction)

 

[henfruit]

it will stop dripping once it cooks all the moisture out of the refractory.

 

[djblech]

I figured out how to turn my gas boiler down after talking to my plumber. The greenwood is working much better now thwt it is burning hotter. It still smells smokey in my garage. Is this a common thing with wood boilers? I figured out that I should only open the door when the damper is open as there is less smoke. I am goining through more wood but that is to be expected as I am heating the Whole (2200 sq ft) house now.
Thanks for the help
djblech

 

[henfruit]

what do you consider a lot of wood? how often are you filling it and how full with what type of wood splits or round?

 

[djblech]

I have been loading the furnace with about 5 or 6 maple rounds, 8" to 14" in diameter. This wood is dry, about 3 years. The furnace is not full, but about 1/4 up the door. This is not quite lasting 8 hrs. When I check at 8 hrs there is some coals and the temp is down to 120. I have 2 radiant heat zones in my house. A 14x22 front porch/family room and a back porch mud room. I think these are sucking alot of heat. The back porch will not catch up. I have a wood stove (Vermont Castings) in the family room that we usually use. I never used the radiant with the gas boiler because it cost to much.
Thanks
Djblech

 

[henfruit]

the radiant should work just fine. if i let mine burn out it will take a good day to get that low. you should get a good 8 to 10 hour burn with the temp at the end of the burn at 140 t0 160.i have forced hot air and have no problem keeping this place warm.

 

[djblech]

I had my draft tested today and it looks like I have to much draft. My draft measured 13 pascals and went up to over 20 when the draft was open. I think my greenwood manual says 12 to 17. I had added 5 ft to the chimney before I fired because I thought that I wouldn't have enough draft. Looks like I can take 2 ft off and try that. That might be why I am using more wood. Looks like -25 tonight. Hope the furnace keeps up.
djblech

Stihl 170 + 360
Kioti dk45 and a Farmi winch
120 acres woods
Greenwood 100

 

[henfruit]

you should be getting .05 to .07 for the proper draft. i get it a little higher when the boiler is putting out good heat. i went 10 + hours today on 2 rounds and 2 big splits from a 16 in round. it was in the high 20s but the wind was whipping from the north and i face due north toward mt. washington.how tall is your chimeney? you may need a baromectric damper?

 

[djblech]

I took a 3 ft section of chimney off today. Since I have a class A chimney and it is in 2 and 3 ft sections I can adjust the draft somewhat. This seemed to slow the burn down so that it wasn't roaring as much. I still have about 17.5 ft of chimney with about
5 ft over the peak of the garage. -25 last night, I stoked at 10:30 and at 6:00 this morning the fire was down to a few coals and my water temp was down to 110. I'll check it again tonight now that I shortened up the chimney.

djblech

 

[henfruit]

boy some thing is wrong? are you pumping the water from the boiler to a heatexchanger? i got a 11 hour burn over night and still had 160 d water in the am.

 

[2.beans]

have you figured out your heat loss of your house? what size btu is your propane boiler?

 

[whippingwater]

boy some thing is wrong? are you pumping the water from the boiler to a heatexchanger? i got a 11 hour burn over night and still had 160 d water in the am.

You were in the high 20's and he was 25 below. A 50 degree temperature differential and the difference of heat loss between buildings make it impossible to compare the performance of the boilers. If the zone for the back porch is constantly calling for heat because it "can't catch up" this is likely the reason for shorter burn cycles, you're using all available heat.

 

[djblech]

Last night I stoked fire at 10:30. I got up at 6:30 some coals temp down to 120. My return temps are at the most 10 degrees less than the supply temps. My two radiant zones are always calling for heat. They never seem to catch-up. The back porch is small, 8x12 but it won't get above 60 degrees. The front porch, family room, is catching up so I turned the thermostat down to 68. My greenwood seems to cycle (draft open) about every 15 to 20 min. I do have a heat exchanger so that the wood boiler and the gas boiler are seperate. My gas boiler is 80,000 btu I think. I would really like to get at least 8 hrs on a burn.
Any sugestions appreciated.
djblech

 

[2.beans]

assuming your gas boiler would keep up i would ditch the heat exchanger and plumb the boilers parallel if possible. if not hook them in series.

 

[djblech]

I checked my hot water maker and found it was turned up all the way. I am adjusting some of the thermostats to decrease heat demand. I think the back porch temp of 60 is the best I can do there. This is not a problem as it is just a mud room anyway. Because of the water table, my house sticks out of the ground about 2 ft. I think the exposed foundation gives up alot of heat. 2" of foam around the house would probably held alot. Also, My wood is old and dry but may not real solid. I cut it up last summer and got it under cover but it had been down for 3 yrs. I stoked at 10:00 and at 4:00 I still have wood burning. The temp outside is up to about 20 also. I don't think I am losing much heat in the primary loop. It is an insulated 4" pipe with 2-1" pex pipes. I buried it 5' in the ground and put 12" wide 2" thick foam over the pipe before I buried it. I realize that this is a learning process, I really thought I would have tons of excess heat to get rid of and this is not the case.
Thanks
djblech

Greenwood 100

 

[ISeeDeadBTUs]

Any progress?

A question for you . . . . Do you have some mechanism to keep the 'short loop' running whenever the GW is giving you heat? If the GW is up to temp and the gas boiler isn't, sounds like you have a problem exchanging heat.

My 'short loop' has a circulator which is triggered by a strap-on aquastat from the supply-side of the 'long loop', which is set at 162. I have also unplugged my oil burner for now.

Jimbo

 

[djblech]

Jimbo,
When I found and turned down the kick-in aquastat for the gas boiler to 140, it hasn't kicked in since. I have 2 pumps on the gas boiler, 1 for the main house and 1 for the radiant zones. They are hooked into the short loop and seem to be running whenever there is hot water. I went out at 6:00 and stoked fire there was a good bed of coals, but the water temp was down to 120. I can't seem to get more than a 6 or 7 hour burn. I was reading my owners manual this am. It said that the greenwood was designed to run at 140 to 170 degrees. My damper aquastat was set for 180. I was getting 190 after the damper closed so I turned the aquastat down to 170.(damper shut) Maybe this will increase my burn times.
Thanks
djblech

Greenwood 100

 

[trailhound68]

There are so many things to consider, where do you begin? It sounds to me as if you could stand to raise your temp some. In colder weather I tend to raise my temp and allow it to go up to 205. On average my stat is set at 185 w/ a 15 deg diff. If water temps are not hot enough you may never satisfy the thermostat, circ pumps will just run and run.
Dry dry wood will burn very hot, but very fast. I have seen some 650+ stack temps with a full load of dry wood.
Mine too drafts too much. I took 4' off of mine and installed a damper. Works well.

 

[2.beans]

can you check your boiler supply temp where it enters your house to see what your losing from your boiler? i built pipe like yours and got infested with ground water and would lose 15 to 20 * between my boiler and house in a 250' run. i got to change that.

 

[djblech]

Turning down the draft aquastat did not work at all. The heat retension unit shuts down the furnace if the temp gets blow 140. This is measured outside the manifold pipe with a sensor. So I turned it up to 185. This seems to be working better. I am running 2 pumps constant. 1 circulating water through the furnace (greenwood specs) and 1 circulating water through the loop to the house heat exchanger. There is another pump on the back of the furnace that mixes hot water to the return if it drops below 140. I hope I don't have water in my garage to house loop. It was a premade pipe that came with a 4" solid drain tile with the 2-1" pex pipes and the insulation already installed. I had been quoted $11.00/ft and I found this at my local fleet supply.(farm store)for $5.75 /ft They started selling OWB and all the parts that go with. They had sold out of that pipe by Sept.
I built this house in 1994 and I am beginning to think that it is hard to heat. I do have alot of windows, and I have blown fiberglass in the attic that I should probably cap off with some celulose. Projects for another day.

djblech
Greenwood 100 no storage