Question Re: Maintaining Heat

[MandoLinda]

The square footage of my house, a log-sided home, is approximately 1700 square feet, but I have a high cathedral ceiling and one wall consists of 3 sliding patio doors, so that wall has no registers. I do have a ceiling fan, but it isn't effective if there is no warm air to push down.

Thus far I've called the nice Tarm folks, and they are going to stop by to look at isolating the oil boiler, so I'm not using oil to heat the water passing through the wood boiler, which is what is happening; I've trying to find a reputable weatherization company in NH (Eversource is not an option) and I'm having a leaky patio door replaced. I am scrapping the metal blinds on my windows and am looking at cellular shades. And I'm learning to knit.

I called the storage tank folks. I have an EPDM liner in my atmospheric and they concur that I shouldn't be heating this above 170 degrees (I am using the top most temperature reading since that is the highest temperature). They are thinking I have an emitter problem. Currently, I have slant fin emitters, so I am looking at getting something more efficient.

I'm off to knit and earn a degree is thermodynamics.

 

[Fred61]

I tried knitting last year but soon gave up at the beginning of my first project. Tried knitting a set of radial tires.

 

[dogwood]

I'm off to knit and earn a degree is thermodynamics.

That's a scream Linda. Have you considered knitting a coverlet to go over the tank?

Your system and amount of storage should be able to handle that amount of square footage readily. Slantfin is a reputable brand. I bet Tarm says you need a bit more of it, rather than to replace it.

Is it prohibitive to change the EDPM liner to something better that can take storage up to a more reasonable limit. You need to have a way to measure temps at the middle and bottom of the tank at least, to know how much heat is in the tank and be able to figure out how much wood to burn at any one time. Top measurement alone is not very helpful by itself.

When you're done knitting, take a look at Nofossil's site. http://www.nofossil.org/ You might find it interesting, then again maybe not. He's got some expertise, the kind Boiled Over describes, and I think he has open storage like you. I believe he's up in New Hampshire too. Must be a wood boiler Mecca up there. Sounds like you're making some headway.

You should've stuck with macrame Fred, instead of trying to show off.

Mike

 

[Potsdam]

I would like to poke in a couple comments to chew on.
1) Does the Tarm have a Tarm Loading Unit or some brand of boiler temperature mixing control valve? The Tarm Loading unit on my boiler turns on via an aquastat mounted on the supply line as close to the boiler as possible. Its set at 150F. Without a full understanding of your systems design, if you have a loading unit or circulator pump working with a mixing valve......your boiler can operate with water circulation at a lower temp than 170F. This set point was the first thing that jumped out as a definite easy issue to resolve and move on to other items to correct.
2) The aquastat on the storage would need to be moved lower, but concerns with the liner above 170F is certainly a constraining issue in itself. 700 gallons for 1700sqft should be more than adequate considering the boiler and available storage....again, constrained with this 170F is problematic. I completely agree your not getting a full btu charge into storage. Your piping to storage could also be an issue if its not moving enough water from the boiler to it and causing the boiler to warm up long before your storage reaches 170F causing the boiler to short cycle until the storage is up to temperature. Starting with 170F at night and ending with 152F in the morning seems too be a good run for your storage without having a full btu charge and no wood fire in the boiler.
3) Investigate into your complete controls package and evaluate if you can break the oil burner circuit with a 2 way aquastat. Meaning if your boiler or your water supply loop is above 140F .... it keeps the oil burner circuit open until the loop fall below 140F. This would give you the sense that if your wood boiler is out of wood or storage is too far depleted, the system clicks over to the oil boiler. The aquastat functions the opposite too. The house would be normally on the oil burner until you decide to start the wood boiler. Once the Tarm warms up to that trigger point set on the aquastat...the system shifts to heating from the Tarm.
What I'm trying to convey is you may need more flexibility in your water temperature operating range (ie. 140F-170F).until you can achieve more btu storage. I am pressurized and I see just above 200F top and bottom when tanks are fully charged and boiler shuts down.
Tarm will be a huge help to get that system running better and keeping the costs down.

 

[dogwood]

Hey Potsdam, what kind of boiler do you have that can get your storage to 200 degrees before it shuts down. My Solo Innova shuts down at 180 degrees. Tarm Biomass said not to do anything to try to raise that cutoff temp. I was trying to figure out how to do just that for a minute, but finally decided to let it be. I found Jebatty's achieving 190 degree storage temps with his Tarm irritating enough, but your 200 degree storage temps are truly insufferable. Mandolinda's 170 degree limit would truly be unbearable and is probably what's driven her to take up knitting. Sorry to intrude on your thread Mandolinda.

Mike

 

[maple1]

180 shut down? Really? Yes, I would find that hard to live with also. That would likely not allow me a second lap through storage. With 140 min return, lap 1 gets me to 160-165, then lap 2 gets me in the 180-190 area on top.

Mine will go as high as I let it, limited only by dump zone aquastat setting. But I usually don't go much more than halfway through lap 2 before the fire is dead or dying.

 

[Potsdam]

I have a Scandtec Solo 40. It does shut down at 180 but my discharge water at peak is running at 200 when the boiler idles. The rise in temp on the boiler continues for a couple minutes also until it retreats but never pushes past 205. This continues to transfer to the tanks. I will get some pixs posted in the next couple days. Must mention that my dry well temp gauges are $15 a piece, not big money but worthy enough for my purposes. I did nothing for control mods on my Tarm, its as I bought it new.

 

[Clarkbug]

So I have a random thought.... You mentioned that you have a Tarm solo, correct? Those were (in theory) designed to be able to cycle without needing storage. As you stated, they would potentially create smoke/creosote when run that way, so the storage tank is a good means of alleviating that issue. I wonder if the previous owner of the house would charge storage, and then load to allow the boiler to cycle to try and maintain the 170. Then you have the benefit of having storage hot and whatever wood is in the boiler. Not that its the best/most efficient way, but its a potential explanation for how it was run previously.

Maybe I missed it, but does your tank with the liner have multiple heat exchangers in it? If so, that also limits you because of the approach temperatures between what your boiler puts out and what you need for your fin tube radiation.

When you hear from the folks at Tarm and potentially the audit people, post back to let us know!

 

[hondaracer2oo4]

That’s a good catch Clark on the fact that the boiler can operate with no storage and thus extending the heating hours greatly by first heating the storage to temp by exhausting the first load and then refilling. My owb gasser with 200 gallons of on board storage idles for about 2-3 hours between firings and has zero creosote past the firebox.

 

[MandoLinda]

A quick update - Thermal patio door curtains and cellular window shades - on order. Yankee Thermal Imaging performed an energy audit, and I am eligible for cost-sharing with my electric company - so I am having about $7,500 in energy improvements performed (mostly attic and basement insulation). Hopefully this will be scheduled within the next 45 days. My plumbing and heating company stopped by and couldn't figure out my system - but estimated that I am about 10 feet short of radiator in the living room (20 foot high ceiling with three patio doors). I have avoided freezing to death by running my wood stove and wood boiler at the same time. I've burned about 275 gallons of oil this winter, using it in the morning, when I come home too late to run wood, and when I'm demoralized.

Last night, I discovered a small puddle near my atmospheric EPDM storage tank, so I will need to call TARM this morning.

My conclusion: My wood boiler and storage system is 15 years old. If I have to put $2,000 or $3,000 into upgrades, then I'm done. I could invest in a new oil boiler and/or heat pump instead. Technology has come a long way. I like using the wood stove - it's simple, quick to light, quick to heat - but this boiler, and the work that does into it, is exhausting.

 

[peakbagger]

FYI there may be rebates on a mini split heat pump. The down side is their heat output drops with temperature so they dont replace a source of heat for real cold weather. I use mine to about 20 degrees although I have kept the house warm down to 10 degrees but I was pushing it. American Solar Technics in Maine http://www.americansolartechnics.com/ can make a new custom liner which should be made out of PVC not EPDM. I think his liners are lifetime guarantee.

I really think you need to get someone who understands woodboilers to look at the system before you spend anymore money on it. Have them take a good look at what temps the oil boiler is running at as I suspect your lack of baseboard means they have the supply temp cranked up. One other thing that could really screw things up is if the thermal storage tank isnt full of water. The water level will gradually drop and if you dont fill it on occasion, it will not store much heat. Its a PITA on my AST tank to check as I need to check with a stick down a vent pipe. I do it once a season but I think AST recommends checking it monthly. Be careful, my tank requires head space to account for the change in density as the water heats up. If the tank is filled too high, when it heats up it will run out of expansion space and lift the cover up or possibly damage the liner.

Most everyone switches to a wood boiler with storage to reduce the amount of work heating a house. It odd to hear of someone that thinks they would go back to a woodstove after using a properly operating wood boiler with storage. I expect that once you have your energy work done the difference is going to be night and day. I think there is something fundamentally wrong with your wood boiler setup or the amount of radiators in the house or it just that the house is such a energy sieve that the system is just not balanced to match the obscene heat load.

The other question is how much wood did you burn this winter and how dry was it?. A wood boiler or a wood stove can go through a lot of wood if is not dried properly for two years. If you ever hear it hiss whe burning, it is not dry. Up Gorham (NH) I can heat my home with no oil and no heat pump with about 4 cords of dry wood with my wood boiler. Add in the heat pump and I drop my use by about a cord. If I have damp wood that is not dry I could be up to 6 cords. I added some oil to my tank about 4 winters ago and still have some left so my oil usage is really only when I am gone during extended cold periods where the minisplit cant keep up which is rare.

 

[Bad LP]

Until I got my system figured out with it's little quirks I got a little frustrated. Mind you I'm very mechanically inclined. I've gone from walking in the house for a long weekend and firing up the wood stove to instead firing up the wood boiler. Wood stove has been lit 3 times so far this winter and one of those times was because my wife wanted to watch the fire.

I do however understand your frustration and seeing a leak would only add to it. Fact is heating with wood is not for everybody.