normal stratification; balancing valve questions

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penfrydd

Member
Jul 7, 2008
80
Western MA
www.penfrydd.com
New install of Tarm 140 with storage. First fire yesterday, 850 gal tank currently at 131 (top) all the way down to 59 degrees (bottom. It started at 47 for the whole thing.

How much stratification is normal?

I think I'm having trouble getting all the air out of the system.

Beyond that...the balancing valve above the Termovar. The instructions say to never fully open and never fully close, but to adjust as necessary. However, nowhere does it mention what to adjust towards. What's the goal? I have a feeling that I should be getting a higher percentage of water from the tank to mix with the rest of the loop, but if the water coming in from the bottom of the tank is too cold, the Termovar isn't going to let it in anyway; correct?

penfrydd
 
I think the more the better. On my system I can often get an 80 to 90 degree difference in temp from top to bottom both on charge and discharge. Eventually it heats the whole tank to the same temp.
 
Do you have a verticle or horizontal tank. Pressurized I assume ?
 
that seems really good for a non presserized as long as the bottom gets hot. I'm currious what temps others get.
 
I probably won't be much help. I've got the loading valve that does all the work for me. But on my first fire of system( a few yrs ago) it took a couple of hours to get the air out. But i put one of the bigger size vents up high in my system. Usually in one firing I can bring my tank from about 110 to 170ish on top and about 150ish on bottom. The very first firing I brought the tank from 47 to 180 in about 12 hours, while heating the house in mid winter.
 
I've got a top of the line vent, but, of course, there are all sorts of zigs and zags in my piping. But I think the air issue is disappearing.

As far as the balancing valve goes, I've turned it more towards closed, which slightly raises the temp of the return from storage (just by feeling pipe with my hand).

But I don't see why the termovar doesn't do that. It amounts to two different valves limiting flow.

penfrydd
 
The thermostatic 3-way valves are designed to operate over a large range of operating conditions. Keeps inventory lower. That's why the ball valve is called a balancing valve. It helps balancing the flows for your particular pipes and pumps, etc.

The idea for such a simple device, I think, is to find the best compromise of average return temps over the whole burn. That's going to be hard to do well without a few thermometers.

If you want more precise return temperature control you'll need to step up to the even more expensive loading units or get into electronic control systems like a few intrepid folks around here (and Econoburn, too, I think) are using.
 
I believe we both have the same stss storage tanks and Taylor thermometers. After a full load of dry wood I'll see temps at the top 185,
mid 168, bottom 148. My last fire was Friday afternoon. I have not even looked today but with this cooler weather I'll bet I've got 115 top, 105 mid, and 96 bottom. As soon as I post this I'm going to start a fire. In the side seasons you should be able to go on storage for 2 or 3 days, depending on insulation. Sweetheat
 
How is your tank insulated, and how tall is the tank. From the threads I have been reading it seems that the average stratification is approx 10F per ft. When you are reading the tank temps, the sensors should be roughly 8" from the top or bottom, or it will throw your #s off.
 
balancing valve should be 1/8 open! Sweetheat
 
I have a tall 64 inch high tank under the stairs with Hx coils lifted off the floor one foot. Sweetheat
 
thanks for the info, sweetheat.

I've been burning wood since 1975. Had an old Riteway which served me well for many years. Got an early gassifier (Eshland Wood-gun) in 1985, but didn't do storage. Burned oil for about the last 12 years and finally have the Tarm installed.

I'm sure all will work fine, it just takes a while to get used to any wood burning device. I do think the operator's manual that came with the Tarm could have been a bit clearer, here and there.

I had put in my own hydronic system about 20 years ago, but never worked with 1 1/4 copper before. It's just not as easy as smaller sizes, but I'm pleased with it.

Thanks again,

penfrydd

a wood boiler
stuff to burn
a bunch of machines to cut it with
a tractor to move it
sons and grandsons to move stuff when they're around
 
After your second winter you will be astonished at how easy it can be. This is my 3rd season and I'm very happy. My wood consumption this year and last was 2.5 cords a winter. That keeps a 28X42 shop 64 degrees 24/7. Seems the operating manual for the Tarm is lacking. We had a hard time getting the balancing valve adjusted correctly too. I run with the secondary combustion damper about in the middle or just a bit right of center. Gets a nice yellow/blue flame in the chamber. Happy heating! Sweetheat
 
my tank is 64 wide X 70.5 inches high = 806 gallons Insulation is 2" thick polyisocyanate. my stratification is about 10 degrees different. Sweetheat
 
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