Tarm questions after first 9 weeks of use: With a few notes

[Birdman]

1. How do i clean out the ash at the bottom of the heat exchange tubes? I mean when i sweep out the ash with the long tool provided by Tarm... I can't really get behind the U shaped refractory thing?

2. I have a Series set up. I have closed the valve near the Termovar halfway. However... when 3 zones are calling all at once.. the output temp is not as hot ( due to returning water ?). How else can I get hotter water to my zones when this occurs?

3. If I let the Tarm go out... and let the oil burner take over... will my output water heat be nice and high? ( 180 degrees ) like before?

4. Its going to get real cold here.. I know the fault is not with the Tarm.. it is my house that is not very efficient when it comes to keeping the cold out. It works great when the temp is 10 degrees or higher with occasional dips to 0 degrees. However... when it is continued cold.. like under 10 degrees for 2 or 3 days... my house won't get above 64. Not bad... but I would like it warmer. Of course a house inspector would say.... DUH.... its not the heating units fault... it is because you have air leaking into the house and not enough insulation. I can work on that this summer.. but i don't hav ethe time or means to do it now.

5. Looks like I will use 6 cord this year... at the rate i am at. I was guessing 5. I have plenty of wood so no prob.

 

[WoodNotOil]

1. How do i clean out the ash at the bottom of the heat exchange tubes? I mean when i sweep out the ash with the long tool provided by Tarm... I can't really get behind the U shaped refractory thing?

Do the best you can and don't worry about it. I don't think it impacts it too much.

2. I have a Series set up. I have closed the valve near the Termovar halfway. However... when 3 zones are calling all at once.. the output temp is not as hot ( due to returning water ?). How else can I get hotter water to my zones when this occurs?

You can also choke off the the return shutoffs for each zone to minimize flow a little. There is no good solution for this other than repiping: Parallel, P/S, or hydraulic separator. When it gets really cold out I crank the Tarm up into the 190* range which raises the OB temp a little and helps get the heat out. I also prioritized my zones using a DPDT relay so only two out of the three zones run at once.

3. If I let the Tarm go out... and let the oil burner take over... will my output water heat be nice and high? ( 180 degrees ) like before?

If you have the OB set to heat that high it will. I think Tarm suggests a 140 low and 150 high for it. You have to have it set lower unless you wire the OB aquastat through a relay that keeps it from running when the Tarm circ is on.

4. Its going to get real cold here.. I know the fault is not with the Tarm.. it is my house that is not very efficient when it comes to keeping the cold out. It works great when the temp is 10 degrees or higher with occasional dips to 0 degrees. However... when it is continued cold.. like under 10 degrees for 2 or 3 days... my house won't get above 64. Not bad... but I would like it warmer. Of course a house inspector would say.... DUH.... its not the heating units fault... it is because you have air leaking into the house and not enough insulation. I can work on that this summer.. but i don't hav ethe time or means to do it now.

Once again crank the Tarm up to like 195* and it should help a little.

5. Looks like I will use 6 cord this year... at the rate i am at. I was guessing 5. I have plenty of wood so no prob.

If you had put in an OWB you would probably have burned 3-4x that amount. That is pretty good useage for a drafty house. I use about that to heat my drafty house, but I also use wood in the summer now for DHW.

 

[jebatty]

the output temp is not as hot ( due to returning water ?). How else can I get hotter water to my zones when this occurs?

I think your Tarm always should be putting out 160F+ water. The question will be how much. My Tarm 40 will consistently put out 110-140,000 btu's. The Termovar will divert output to maintain 140-160 minimum return temp. Ideally all excess will go to the zones.

Get a handle on your performance by getting some probe-type thermometers (milk frothing types work really well; see ebay). Put one on your boiler out put from Termovar to system, system return to Termovar, and Termovar return to boiler (maybe also other points of interest). Also monitor your flue probe thermometer. Zip tie them to the plumbing and wrap insulation around each (except the flue probe).

In my experience, I typically see something like this:
Flue probe: 450-525
Termovar to system: 170-200
System return to Termovar: 130-150; what are you seeing?
Termovar to boiler: 140-165

What do you show? It's really hard to diagnose perceived problems without the data to help explain what is happening.

If your flue probe is not in the range mentioned (or maybe above to as much as 600-700, which I think is too high), then you're not maintaining a good burn. Is your wood too big? too wet?

 

[WoodNotOil]

the output temp is not as hot ( due to returning water ?). How else can I get hotter water to my zones when this occurs?

I think your Tarm always should be putting out 160F+ water. The question will be how much. My Tarm 40 will consistently put out 110-140,000 btu's. The Termovar will divert output to maintain 140-160 minimum return temp. Ideally all excess will go to the zones.

Get a handle on your performance by getting some probe-type thermometers (milk frothing types work really well; see ebay). Put one on your boiler out put from Termovar to system, system return to Termovar, and Termovar return to boiler (maybe also other points of interest). Also monitor your flue probe thermometer. Zip tie them to the plumbing and wrap insulation around each (except the flue probe).

In my experience, I typically see something like this:
Flue probe: 450-525
Termovar to system: 170-200
System return to Termovar: 130-150; what are you seeing?
Termovar to boiler: 140-165

What do you show? It's really hard to diagnose perceived problems without the data to help explain what is happening.

If your flue probe is not in the range mentioned (or maybe above to as much as 600-700, which I think is too high), then you're not maintaining a good burn. Is your wood too big? too wet?

His problem is he has a series hookup where the Tarm supply mixes with the zone return before going into the OB and then goes from there out to the zones again. I don't think it is a burn problem at all.

 

[jebatty]

Apologize if I misunderstood. If WoodNotOil is correct, you're heating lots of water over ??? feet of plumbing with ??? heat loss and lots of variables. Why not just heat your house with the Tarm, put in a bypass and skip the OB completely?

 

[Birdman]

Bypass sounds like good idea. Are there any disadvantages to it? For example... if I couldn't make it home to add more wood and the system was calling for heat? Will the fan just turn off when it hits its low spot. If the worst case was that the system cools down momentarily until I get home to add more wood.. I guess i could live with that. Also... let us say i did this. Are we saying my water will be 10-20 degrees higher going out to the zones? If so... that would be awesome. That would also mean less wood consumption? Also.. can someone throw out a number as to how much I might pay a plumber to do this? Let's just say worst case scenario? 500 bucks? Would I get longer idle times?.. because more heat is going to the house. I do not have storage. Which brings me to another question... STORAGE. With my current system in series... how would valving off my OB work with storage? How does the storage work when heating my house? Would the heated water from the storage mix in with the cooler water from the returns before going out to heat the zone again ... like with my current set up? OR does the storage water go directly to the zones?

 

[Eric Johnson]

I have a series setup and I can't bypass my gas boiler without a major repiping job, so I use it like it is and it works fine. The way I addressed the "water in the gas boiler is not hot enough when pumped into the zones" was simply by running the circulator circuit through an aquastat in the gas boiler set for 140. In other words, the zone pumps can't kick on until the water in the gas boiler is at least 140 degrees, even though the room stats are calling for heat. I think this is more efficient, since you're not pumping tepid water around every time the zone calls for heat.