Tarm Solo 40 Low Stack Temp and Condensation

[Firebox21]

Hi Everyone,

I bought a house with a 15year Tarm solo 40 wood boiler. The first year the unit ran with no issues and seemed dummy proof. However, last year was a different expeirence. I replaced the stack pipe with 24guage stove pipe last fall as the orignal had seen better days. I followed the same procedures, but my stack kept leaking black condesation so I bought a heat gun and I noticed the stack temps were dropping below 120F when the draft fan would shut off. The stack temp will climb to 330-500F with the draft fan running. I have read numerous other older posts trying to find if a similar issue. I have a mositure meter and the wood was 6-12% last year so I don't think its wet wood issue. I thought about chopping my wood into small width pieces for this year, I kept the secondary air in the middle. I just learned about the primary air flow adjustment and will see where that is at. I replaced the gaskets on the load door and clean out door as I saw some gummy black creosote forming on the load door and the little flat edge behind the load door. I also can visibily see some mosuiture build on the sight glass. I clean the tubes every two weeks as the book states. I do not have a storage tank, so I assume this boiler churns until a zone calls for heat. Any advice would be greatly appreciated.

 

[peakbagger]

The solo 40 was designed to run with storage. Tarm would not warranty an installation without it. It should get better as it gets colder and there is more heat demand.

 

[flyingcow]

Just curious about your moisture content.

Im assuming your wood has been cutt/split/stacked for at least 1 year? And when you check the moisture you split the piece of wood take a reading on the inside?

 

[sloeffle]

Just curious about your moisture content.

Im assuming your wood has been cutt/split/stacked for at least 1 year? And when you check the moisture you split the piece of wood take a reading on the inside?

I agree, 6 - 12% sounds a little suspect. You are getting into kiln dried wood territory for those kind of readings.

 

[flyingcow]

I agree, 6 - 12% sounds a little suspect. You are getting into kiln dried wood territory for those kind of readings.

I agree

I do have hardwood thats in the mid teens. But its 2 solid years cu/split/stacked.
Stuff makes great heat.

 

[pettibone]

Hi Everyone,

I bought a house with a 15year Tarm solo 40 wood boiler. The first year the unit ran with no issues and seemed dummy proof. However, last year was a different expeirence. I replaced the stack pipe with 24guage stove pipe last fall as the orignal had seen better days. I followed the same procedures, but my stack kept leaking black condesation so I bought a heat gun and I noticed the stack temps were dropping below 120F when the draft fan would shut off. The stack temp will climb to 330-500F with the draft fan running. I have read numerous other older posts trying to find if a similar issue. I have a mositure meter and the wood was 6-12% last year so I don't think its wet wood issue. I thought about chopping my wood into small width pieces for this year, I kept the secondary air in the middle. I just learned about the primary air flow adjustment and will see where that is at. I replaced the gaskets on the load door and clean out door as I saw some gummy black creosote forming on the load door and the little flat edge behind the load door. I also can visibily see some mosuiture build on the sight glass. I clean the tubes every two weeks as the book states. I do not have a storage tank, so I assume this boiler churns until a zone calls for heat. Any advice would be greatly appreciated.

 

[pettibone]

I have the same boiler as you, last year was the first year and I had wood between 15 and 25 per cent moisture, although most was in the teens, and have no storage. We had no creosote in the chimney at all. We have a 35 foot stainless liner in the chimney which goes up through the house and the top 25 feet of the liner is insulated. I noticed you didn't describe your chimney other than to say you replaced the pipe but what about the rest, is the pipe the whole chimney or does it just go into a masonry chimney? Is it inside or outside? I don't think storage has anything to do with it but if it's warm outside and you're filling it with wood could cause that issue without the storage. How about a little more info.

 

[brenndatomu]

How about a little more info.

Agreed...the way I read it they replaced the chimney with stove pipe...not good if true
Flue gasses need to stay above or at least very near 250*F clear to the top to avoid heavy condensation and a tendency for creosote.

 

[maple1]

When did you replace all your gaskets?

 

[Firebox21]

The wood was 2 years old last year. Now the supply from last year will be 3 this year. I bought a mositure meter off amazon that had decent reviews. I place the prongs parallel to the grain of the chopped wood for those readings. If there is something more to meausring the mositure in the firewood I would like to learn as it sounds like my readings my be inaccurate from your statements above. The stove pipe goes into a masonary chimney. It is in the center on the home. The home has two stories above the basement so I would think this sufficient. The liner is not metal as mentioned by someone above, I am almost certain it is clay from the looks of it. The door gaskets were replaced two years ago as they looked warn. I then replaced them again last year trying to cross things off a list of possible causes. Are there other gaskets I should be looking into replacing?

 

[pettibone]

It sounds to me that you have a good setup and it doesn't seem to me that your wood wouldn't be dry. The only things I can think of is how hot does the boiler get? I like mine to be 185-195 but if it gets too hot can shut off and need to be reset and was wondering if you cleaned the tubes in the boiler and if they have creosote in them plus the fan will get crud on it where it cuts down on the amount of air going in and need to be cleaned off, but if you have an owners manual you probably know about that stuff. There are no other gaskets beside the doors.

 

[Tonty]

To get a correct moisture reading, you have to take a piece (more than one from several different places on the wood stack to get an average) and split it right before you test it. Than you measure the moisture on the fresh split, NOT on the end grain. Preferably the wood should be a warmish temp first (inside a few hours). That’s maybe how you have been doing it, but just to be clear.
I’d agree, if your wood hasn’t been stored in log length, and has been split and stacked for 3 years, it should be dry.

 

[Highbeam]

To get a correct moisture reading, you have to take a piece (more than one from several different places on the wood stack to get an average) and split it right before you test it. Than you measure the moisture on the fresh split, NOT on the end grain. Preferably the wood should be a warmish temp first (inside a few hours). That’s maybe how you have been doing it, but just to be clear.
I’d agree, if your wood hasn’t been stored in log length, and has been split and stacked for 3 years, it should be dry.

The wood has to be room temperature so those splits being tested need to be in the warm part of the house for over 24 hours. Cold wood leads to drier results by several percentage points.