Termovar problem

[Bad Wolf]

After fighting with damp wood and some other issues, I had to start my system up from dead cold including the storage tank. What I noticed was that once the boiler was up to temp and started circulating the water temp dropped off rapidly and the pump cut out until the boiler was back up to temp again. I thought the Termovar valve was supposed to bleed hot water into the return to maintain 160 degrees until the return was up to temp. What I get is water as cold as 145 and as hot as 168 once I got the house warm and the tank backup to temp. This leads me to believe the valve is stuck somewhere in the middle. I called Bioheat and Randy suggested I take it out, open it up and see if anything is caught in there.
I'm a little hesitant to remove this when the temp is dropping so low. If I break it then I'm SOL until I can get a new one or by pass it.
Any precautions I need to take? Anybody else had to mess with the valve?

Thanks

Greg H

 

[Singed Eyebrows]

That sounds like a plan. There is too much flow through the boiler & not enough mixing as you mentioned. It is important that you have a Y strainer on the Term inlet, preferably 1 1/4" so you don't get debris in there, Randy

 

[barnartist]

I have in front of me a termovar valve. I remember having to do something similar in the past. It is tough, but you can get inside of it to check for debris. Wait till your boiler is out of fuel to start or you risk boiler overheat if you do not get it back together quickly.

You should have built in shut off valves at each end of the Termovar. Use a pair of flat pliers to turn them to the off position. Take of the plate of the valve and inside you will see the spring.
Now as I sit here and do this myself, I found a sunflower seed in mine! At this point I believe you can acsess the valve by squeezing the ring, the whole valve will slide out. I did it here with no othe tools.
If you find no debris, you might have a flow problem.

This is very simple to do if you have a clear path to your Termovar and a little room to work.

 

[flyingcow]

6mm wrench will work best for the valve shutoff. I've had my loading valve apart. To replace the t-stat.

 

[jebatty]

On reinstall you might have a problem with the paper/fiber washers sealing well. Mine tore. You can easily make new ones from fiber gasket material. The outside diameter is fairly critical, but the inside opening is not. I rubbed the new gaskets with vaseline so that the fittings would slip over rather than bind the gaskets when the fittings were tightened. No problem then.

 

[barnartist]

You wont need to uninstall anything though Jebbetty, all of this can be done with unit still on the piping.

 

[jebatty]

Read your post too fast and missed this. Good advice.

 

[WRVERMONT]

I may be missing something, but don't most of these valves (depending on the element) insure a return temp of around 140deg F to the return not 160 deg as you said at the beginning of this thread? As the storage get,s hotter the return is going to go up into the nieghborhood of 165 as you indicated. are you sure the valve is faulty in it's operation. At start up, inorder to warm up the boiler, the pump may cycle some until the boiler it self is warm. Not sure if maybe I'm missing some info on the problem.

 

[jebatty]

The Termovar may be purchased with different temperature settings. Regardless, the balancing valve setting will impact the actual boiler return water temperature. The balancing valve limits the amount of hot water boiler supply provided to the Termovar, and therefore the amount of hot water available for mixing with cold system return. Although I normally leave my balancing valve at a setting which assures a minimum of 140F, but more normally 150F, I will open the valve more if I have fairly cold system return water, as I did last week when I returned after a 9 day trip and my storage was down to 45F. I had to open the balancing valve substantially to get the 140-150F return water.

Another important factor is that based on my measurements of boiler performance, my Tarm appears quite conclusively to operate better with return water at 160F minimum than with cooler return water. The hotter water around the firebox appears to insure better burn, production of wood gas, and improved gasification, and therefore increased btu output than occurs with cooler return water.

 

[chuck172]

barnartist, I took apart my termovar. I got to the part with the spring. What do I do, squeeze the spring together and pull out? How do I access the thermostat ?

 

[chuck172]

Never mind on the termovar disassembly. Pretty idiot proof. Thanks anyway.

 

[webie]

As long as we are talking about these termovar's ? Does anyone have any stats on what temp these valves start to open and at what temp they are fully open . I know mine will bleed mixed return water back at about 154 degrees and go up from there . It all depends on my system return temp and the boiler temp . I also have after 8 years still trying to figure out the logic in the balancing valve because the more that I close it to cool the return water the less heat get in the house , It seems to me the more I open the valve to supply more hot water for mixing the more flow I get out .
There doesn't seem to be much logic in if you have a termovar to automatically mix the return water that you need to also try to do it manually on a ball valve unless the termovar doesn't work .
If some one can explain how this should all work I would really like to know .

 

[Singed Eyebrows]

The Termovar may be purchased with different temperature settings. Regardless, the balancing valve setting will impact the actual boiler return water temperature. The balancing valve limits the amount of hot water boiler supply provided to the Termovar, and therefore the amount of hot water available for mixing with cold system return. Although I normally leave my balancing valve at a setting which assures a minimum of 140F, but more normally 150F, I will open the valve more if I have fairly cold system return water, as I did last week when I returned after a 9 day trip and my storage was down to 45F. I had to open the balancing valve substantially to get the 140-150F return water.

Another important factor is that based on my measurements of boiler performance, my Tarm appears quite conclusively to operate better with return water at 160F minimum than with cooler return water. The hotter water around the firebox appears to insure better burn, production of wood gas, and improved gasification, and therefore increased btu output than occurs with cooler return water.

Jim; I'm somewhat confused. Isn't the Termovar basically the same as the Laddomat? When my boiler is up to temp I do not understand how return water temp will affect anything. The return temp into the Lado is not return temp into the boiler because of mixing. Maybe I haven't been reading the gauges on the Lado correctly. I though that if my boiler thermometer read 78C & the Lado had opened at 78C that my firebox water should be at 78C. No balancing valve is ever talked about in any Lado instructions I've seen. This is just my first week up & running, Randy

 

[chuck172]

Think of the laddomat as having a built in automatic ball valve which is throttled for optimal return temperatures to the boiler.
A laddomat is a termovar on steroids.

 

[Singed Eyebrows]

Think of the laddomat as having a built in automatic ball valve which is throttled for optimal return temperatures to the boiler.
A laddomat is a termovar on steroids.

Thanks Chuck, I've got a lot to learn on boiler controls, Randy

 

[jebatty]

As long as we are talking about these termovar's ? Does anyone have any stats on what temp these valves start to open and at what temp they are fully open.

As with most kinds of documented information, a quick google gets the results. Here is the spec sheet on the Termovar: spec sheet

I think, though, there is more to your question. Before anything else, make sure it is installed correctly.

 

[flyingcow]

Loading valve is different than a TV-2 or 1 can't remember which is what. The loading valve takes the place of having to put in a ball valve for mixing, and it's got a t-stat on a spring that will close as the water from the boiler gets hot. Works really good. i know i'm not explaining it right. If i had a link it would show you the % of open/close according to the boiler temp.

 

[DaveBP]

I'm not sure this thread hasn't got a little terminology confusion going. The Laddomat most folks talk about is the Laddomat charging unit, model 21 seems to be the most common on this side of the water. The "Termovar" can be the loading valve or the loading (charging) unit. Bloody Swedes aren't using the same dictionary to translate from.

The Laddomat Charging Unit and the Termovar Loading Unit are the devices that combine the thermostatic valve and circulator and other hardware into one casting. The Termovar Loading Valve is the more simple 3-way thermostatic mixing valve.

This confusion has derailed more than a few otherwise lovely threads.

But then I have worked too many 2nd shifts this week and am sleep deprived. Maybe it's me that can't keep up.

 

[Bad Wolf]

OK I took the termovar (4400) apart to see if it was hanging up. Nothing I could see but now I have a much better idea of how it works. I tested it out by putting it in a pan of water on the stove and watching it.

There is a disk that closes off the return line. When it is cold this is fully closed. When the circ pump kicks in hot water from the boiler flows thru and straight back to the boiler inlet. As the cartridge heats up (around 140) a pin starts to slowly push out and lifts the valve up (its held in place by a spring) This allows some of the cooler return water to mix. As the mixed water gets hotter the valve opens still further.

Even when it is fully open it looks like it would still only be 50/50 betweem the boiler and the return water. Ths is why I have a ball valve on the boiler line I guees.

I would have thought they would have a valve that closes off the boiler water completly once the return reaches a certain temp.

Anyway there was nothing keeping it from closing and opening that I could see, so I put it back together.

 

[barnartist]

nice experiment. 50 50 you think? I don't like the sound of that either if thats correct.

 

[Bad Wolf]

What you see in the pic is almost wide open, The boiler side is totally unrestricted. This is why I have the ball valve set at 1/2 open. I can actually adjust the return on the fly by measuring the temp with the IR thermometer in one hand and the handle of the ball valve in the other. There is a little bit of a lag while the black iron pipe heats up or cools down.
Ideally I have it set at around 160-162 because when the gassifier is running well I can get a 10 degree rise over the inlet temp.

 

[jebatty]

I discovered quite awhile ago that the Termovar never really opens to the point of stopping any boiler feedback. It really hasn't been a problem at all. I happen to use a gate valve, which isn't the best, to limit boiler feedback through the Termovar, only because that's a valve I had. The good part of the gate valve is that the handle is square and I can count 1/4 turns easily to get repeatable settings. If my return water is quite cold, I open the gate valve 6-8 quarter turns. If it is 130F or above, I only open the gate valve 4 quarter turns. Everything works well.

I suppose the main question is, when the Termovar is fully open, even though it still allows some boiler feedback, how restrictive, if any, is it on system return? Restriction would add to system pump head.

Regardless, some form of boiler return water protection must be provided, and the Termovar accomplishes this requirement.

 

[webie]

As long as we are talking about these termovar ? Does anyone have any stats on what temp these valves start to open and at what temp they are fully open . I know mine will bleed mixed return water back at about 154 degrees and go up from there . It all depends on my system return temp and the boiler temp . I also have after 8 years still trying to figure out the logic in the balancing valve because the more that I close it to cool the return water the less heat get in the house , It seems to me the more I open the valve to supply more hot water for mixing the more flow I get out .
There doesn't seem to be much logic in if you have a termovar to automatically mix the return water that you need to also try to do it manually on a ball valve unless the termovar doesn't work .
If some one can explain how this should all work I would really like to know .

thanks GregH for someone actually answering my question I posted earlier

 

[webie]

OK I took the termovar (4400) apart to see if it was hanging up. Nothing I could see but now I have a much better idea of how it works. I tested it out by putting it in a pan of water on the stove and watching it.

There is a disk that closes off the return line. When it is cold this is fully closed. When the circ pump kicks in hot water from the boiler flows thru and straight back to the boiler inlet. As the cartridge heats up (around 140) a pin starts to slowly push out and lifts the valve up (its held in place by a spring) This allows some of the cooler return water of mix. As the mixed water gets hotter the valve opens still further.

Even when it is fully open it looks like it would still only be 50/50 betweem the boiler and the return water. Ths is why I have a ball valve on the boiler line I guees.

I would have thought they would have a valve that closes off the boiler water completly once the return reaches a certain temp.

Anyway there was nothing keeping it from closing and opening that I could see, so I put it back together.

Here is a question to ponder ,If you think and I can beleave this that when The valve is fully open it still looks like a 50/50 mix is what you are saying , Ok I will agree with that .
But think about this then if you close the ball valve some so say instead of being able to supply 5 gpm to 4 gpm for mixing then in reality wouldnt you be slowing your total flow back to the boiler from say 10 gpm to 8 gpm .
( I am only throwing numbers at this )

 

[Bad Wolf]

I think total flow stays the same but by throtling back on the boiler water going to the termovar I'm just forcing more of it to go through the house before it goes back to the boiler.