My main isssue so far this year has been the issue of cool water returning after going out to the zones. I have a series setup with a Tarm 40. If 4 of my zones are calling the return water is cool and I cannot get the outgoing water to be hot enough when it re-circulates. The 4 zones calling for hot water at the same time does not happen alot... but when it does... I really want to keep teh water hot. For example... when it is -26 in the am when i wake up and my house is at 60 and will not climb any higher. The water going out to zones does not get above 130. I had the oil boiler set at ( aquastat low temp? ) 110. I had it set vey low in the beginning because I really wanted to use the least amount of oil possible. I only wanted the boiler to come on... when( or if ) my fan went off. Using this method... my house would occasionally get cooler... but then when i could finally get home and add wood... the temp would climb back up to where i wanted it. Obviously... the weather dictated how quickly I could bring the temp back up. If I got home and 2 zones were calling ( and circulating water at 130)and it was 64 in my house and 20 outside... I could recover it and bring it up to 70 in 3-4 hours. So... now i have decided to crank up the oil boiler setting a bit. I set it at 145. This has helped tremedously during the colder snaps. It keeps a more even heat and I don't have to catch up. If all 4 zones are calling even with teh Tarm up to 190... the oil boiler will kick on and keep the returning water from getting too cool as it goes back through the zones. It will keep temp at the high point of 160 and low point of 145ish. Then... it seems... to not kick on when 3 zones are calling and the Tarm can handle the load... unless of coarse... the temp outside is -20s. Even then.. as long as my zone for hot water is not calling ( fourth zone) then it isn't that bad. My thought is..just keep the oil boiler setting up where it is now. I am ok with spending the money for the oil. Even at this setting I am thinking I will use no more than 75 gallons for the whole heating season? Even if it is 100 gallons? .. ok with that. Makes life easier and warmer. .. and i am still not using over a thousand gallons of fuel that i would normally have to use. Last year ( whole year ) I used a woodstove and 4 cord and 750 gallons of fuel. This is heat and hot water. This year I am hoping to use 6 cord for heat and hot water... and maybe 200 gallons for the year? I do not have storage so i will need the oil for hot water in summer. Benefits this year over last year. Better heat... nore even throu out the house.. and higher temp.. keeping it between 64-70. Also... less mess... woodstove is out of living area and less smoke. Less hassle with wood as teh storage is better situatated forr filling tarm in basement then trying to constantly move small amount to wood stove. 6 cord is all stacked near tarm for easy filling. Also.. i enjoy not waking up at 1 am to fill th ewoodstove. Tarm goes all night and i wake up happy. Next project is to make house better insulated so i can use less wood.
Tarm Notes After Half A Season. New Owner Learning To Tweak
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Unless your zones are really large, the Tarm should have no problem satisfying 4 zones at once. It might take a dip if all 4 zones were full of cold water and all of them came on at once, but that slug of cold water should work its way through and the Tarm should come back up to temp pretty quickly.
Are you getting good solid secondary combustion? I don't know the Tarm adjustments, but it sounds like you're not getting anywhere near the rated output out of it.
Are you getting good solid secondary combustion? I don't know the Tarm adjustments, but it sounds like you're not getting anywhere near the rated output out of it.
I think the output is there... My Tarm shows the temp on its gauge of 190. I think the issue is teh water that returns from the zones is cooler and mixes with the hot water from the tarm before going through the oil boiler and out to the zones again. Isn't that how the Series setup works? This is not a Primary -Secondary setup. ... which is what i would do .. if i could do it all over again. One of my zones is 30 ft of high output baseboard. Which brings me to another question... can i use one of the ball valves near the circulator .. and close it alittel to slow down the rate of water.. will htis increase the heat to that zone?
Using a Tarm Solo 60 and it is carrying my home 100%, zero fuel oil burn. We're in Fairbanks Alaska and just went through a 3 week period of very cold temps between -35 to -50. My return temps at these very cold temps were running around 130- 145, I have a Grundfos 3 speed pump set at the medium setting. I turned the pump to high and found a marked increase in return temps as high as 160. Also faster warm up times in the house. At -45 I was getting 7 hour burn times with birch, on a full load. It is very import that you not let the Tarm fall behind by letting it get to cool. When unit is has used the exsiting fuel load, put more in before it starts to cool. We are not using heat storage. Warmer than -25 I have been turning the circ pump back to med setting. Our home is 2x6 construction, and about a 4.5 star ratting, not sure how that compares to your house. Hope info helps.
Nushagak
Nushagak
As to your zone flow rates, more flow does not always produce equivalent more heat. In general, 1/2" tube flow rate maximizes heat transfer at 1.5 gpm, 3/4" at 4 gpm, and 1" at 8 gpm. Faster than that and the heat won't be transferrred as well to your zones, return temp will go up because heat is not being used by the zones. Your zones need to be well designed to maximize heat transfer at the optimum flow rates.
Birdman, my setup is the same just a different boiler seems like there must be something simple to your fix. You could always try reducing your return by partially closing the valves on those zones to see if you gain faster temp increases. Maybe flow rate is too high -I'm just a dubba though.
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