# Termovar problem



## Bad Wolf (Jan 6, 2010)

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


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## Singed Eyebrows (Jan 6, 2010)

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


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## barnartist (Jan 6, 2010)

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.


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## flyingcow (Jan 7, 2010)

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


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## jebatty (Jan 7, 2010)

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.


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## barnartist (Jan 7, 2010)

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


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## jebatty (Jan 7, 2010)

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


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## WRVERMONT (Jan 7, 2010)

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.


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## jebatty (Jan 7, 2010)

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.


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## chuck172 (Jan 7, 2010)

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 ?


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## chuck172 (Jan 7, 2010)

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


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## webie (Jan 7, 2010)

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 .


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## Singed Eyebrows (Jan 7, 2010)

jebatty said:
			
		

> 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


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## chuck172 (Jan 7, 2010)

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.


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## Singed Eyebrows (Jan 7, 2010)

chuck172 said:
			
		

> 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


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## jebatty (Jan 7, 2010)

webie said:
			
		

> 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.


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## flyingcow (Jan 8, 2010)

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.


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## DaveBP (Jan 9, 2010)

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.


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## Bad Wolf (Jan 9, 2010)

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.


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## barnartist (Jan 9, 2010)

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


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## Bad Wolf (Jan 9, 2010)

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.


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## jebatty (Jan 9, 2010)

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.


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## webie (Jan 9, 2010)

webie said:
			
		

> 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


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## webie (Jan 9, 2010)

Greg H said:
			
		

> 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.
> 
> ...



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 )


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## Bad Wolf (Jan 10, 2010)

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.


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## dogwood (Jan 10, 2010)

Greg, when when the boiler is cold and the valve in your picture is in the closed position, is all return flow from the house loads to the boiler cut off? I think that is what you are saying. Or is it only flow from the line that provides the water from the boiler to mix with the return water, that is being cut off? Or is it flow from both lines? 

I called BioHeat last week with a similar question. They answered that the Termovar cut off any return water from the house loads when the boiler was cold. I didn't understand the mechanics of how this might be accomplished until I saw your explanation and picture. I'll have to take a closer look at the Termovar schematic to see how the valve is situated. Thanks.

Mike


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## Bad Wolf (Jan 10, 2010)

Picture the termovar with the boiler water coming in at 12 o'clock and the water from the house/storage unit coming in at 6 o'clock and the return line back to the boiler going out at 9 o'clock.  When cold, valve is closing off the 6 o'clock side (house) completely, so it is 100% boiler water. As the valve heats up that pin pushes out and lifts the valve up off of the seat allowing  some of the house water to mix.  It actually takes about 20 seconds to move so the responce time is not real fast. 
There is never any restriction of the 12 o'clock (boiler) side of things, thats why I'm saying that balancing valve is what I use to reduce the flow to give the house water a chance. 

Right now my storage is down form over night so I'm seeing 170 form the boiler mixing with 134 from storage to yield 164 back to the boiler return.

When I turned up one of the thermostats, I still had 170 from the boiler but 141 return from the house with a result of 154 to the boiler return.  So at 141 the valve must be farther open.


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## webie (Jan 10, 2010)

Greg , Not sure how your storage tank  is set up but mine I have anti siphon valves on it and these greatly reduce the pumps ability to circulate water  increasing head pressure and reducing GPM.  This is what has puzzeled me was my colder return water from storage was yielding higher mix water temps .


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## jebatty (Jan 11, 2010)

Did a quick check on Termovar operation this afternoon that may be helpful. System return was 133F, boiler supply was 185F, and I set the limiting valve on the Termovar to provide return water at 160F. I have a flowmeter on my system that provides relative information, not exact gpm's due to the way I have it set up. With this configuation, flow was 4.5. I then turned the limiting valve wide open to the Termovar, flow dropped to 2.5 and return water temp rose to 169F. 

I couldn't get a reading with the limiting valve fully closed in this situation, as the 133F system return water quickly closed down the Termovar. Perhaps in the next day or two I will run the system to bring the storage tank bottom above 160F, and then run the test again to see how much flow increases when the limiting valve is fully closed.


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## webie (Jan 11, 2010)

Jebatty that is very interesting  experiment , I would have thought the flow would have stayed the same and just diverted more return water as you closed the limiting valve . I would be courious at where the breaking point is as how much you can close the limiting valve before it starts to limit cold return flow and actually start to decrease the GPM  There  doesnt seem to be a direct relationship to the actual mixed return water temp ( or is there ?) , but at some point the termovar valve must start to say hey thats enough cold return  water and start to slow the cold return  flow  and over all  flow . Obviously you need some flow to open actuate the termovar but how much ?
 I am thinking here to that maybe the best investment for anyone doing an install would be to install a return flowmeter as this is probably the most acurate way of actually setting the diverter valve .


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## jebatty (Jan 11, 2010)

> I am thinking here to that maybe the best investment for anyone doing an install would be to install a return flowmeter as this is probably the most acurate way of actually setting the diverter valve .



Although a flowmeter is useful (especially to calculate btu output and btu transfer), I don't think it is overly helpful in setting the diverter valve, which I am calling a limiting (or balancing) valve. I think the best thing to do is to have a thermometer on the boiler return line after the Termovar, and then set the limiting valve to achieve the target boiler return water temp, 160F for example. When system return water is "cold," the valve needs to be set to allow more boiler output to flow to the Termovar to balance the cold system return and achieve the 160F boiler return temp. As system return temp increases, the valve can be set to allow less boiler output to flow to the Termovar, and if system return temp is 160F or above, the valve can be set to allow no flow to the Termovar, thus allowing all flow to the system and no flow through the Termovar. If too little boiler output hot water is allowed to the Termovar, system return temp will fall below the target of 160F. 

The ideal would be a valve that automatically "precisely" achieves the target boiler return water temp, thus maximizing system flow at all output temperatures. As a practical matter, I think the limiting valve generally can be "set and forget it" based on average system return water temp. If actual boiler return water is +/- 160F by some amount, I doubt there is very much system impact. 

Some say that boiler return water may be as low as 140F. Although, experiments I have done pretty clearly show that maintaining boiler return water at 160F improves boiler btu output. The hotter water around the firebox improves combustion, produces more wood gas, and therefore increase boiler btu output vs a lower boiler return water temp.

Personally, I set the limiting valve to target 150F minimum boiler return water, and then allow return water temp to rise as system return water temp increases. I don't mess with the limiting valve very much.


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## jebatty (Jan 11, 2010)

I repeated the data check on Termovar operation on which I did a quick check yesterday. Here are the results.:

Set the Termovar limiting valve (also might be called a diverter valve or balancing valve) open to result in 160F+/- return water to the boiler:

Boiler return: 158F
System return: 141F
Boiler supply: 177F
Approx gpm: 4.5

Set the Termovar limiting valve fully open so no restriction on boiler feedback flow through the Termovar:

Boiler return: 165F
System return: 142F
Boiler supply: 178F
Approx gpm: 2.5

Note that system flow increased 80% by proper adjustment of the limiting valve to only provide the needed boiler return water protection of 160F+/- instead of no flow restriction through the Termovar.

Charge storage tank to result in 160F+ system return; set the Termovar limiting valve at the same setting which resulted in 158F boiler return as noted above:

Boiler return: 187F
System return: 187F
Boiler supply: 190F
Approx gpm: 7*

With system return 160F+, fully close the Termovar limiting valve so no boiler feedback flow through the Termovar (no boiler return water protection needed):

Boiler return: 187F
System return: 187F
Boiler supply: 190F
Approx gpm: 8.75*

Note that system flow increased 25% by fully closing the limiting valve and bypassing the Termovar when system return was 160F+.

Two important conclusions:

1) A Termovar limiting valve will materially enhance system performance (achieve increased flow) if it is adjusted to provide 160F boiler return water protection rather than no limit on boiler feedback through the Termovar. Measurement of actual boiler return water temperature is important to determine this adjustment.

2)  When system return exceeds 160F, the limiting valve may be fully closed to provide no boiler feedback through the Termovar and system performance will be further enhanced (increased flow).

Comment: the data applies directly only to 160F boiler return water protection. The data likely will produce different results at lower settings of boiler return water protection.

* My system boosts flow when boiler supply temp reaches 188F; flow boost is cut when boiler supply falls to 185F. This flow boost nearly eliminates all boiler idling at the high end of storage charging. Since the flowmeter producing the gpm readings adds about 2 psi to system head, I normally operate the system with the flowmeter bypassed, and my actual flows therefore are greater than shown.


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## Gooserider (Jan 13, 2010)

It almost sounds like you need some sort of Thermal expansion controlled valve on the Termovar boiler supply line, controlled by the temperature on the boiler return line...  

Have it open pretty wide at low boiler temps to get fast warmup on the boiler from a cold start, but start closing down as the boiler return temps got higher and you need less mixing at the Termovar...  It would seem like it would work, but what I don't see is why they couldn't build this sort of functionality into the Termovar in the first place - seems like it wouldn't be that hard to just make it so that the thing would simply shut the boiler supply line off completely as it gets hot - seems like the loading units do this, why can't the simple valves?

Gooserider


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## jebatty (Jan 13, 2010)

This functionality is built into the Termovar, but not as well as it might. The valve does start wide open on the boiler supply side when the return side is cold, and it does not allow any system return until boiler supply reaches about 160F. Then the valve opens on the system return side and closes partially on the boiler supply side. It's just that it could close down more on the boiler supply side without relying so much on the manual limiting valve to limit boiler supply flow through the valve when return water is 160F+ and no boiler return water protection is needed. 

In practical terms, it still is not a big deal. The valve does provides boiler return water protection, which is very important. Because of my storage and how I use my system, which ranges between a low of about 100F to a high of 190F on system return (storage tank depleted to storage tank fully charged), I've learned a reasonable setting for the limiting valve on a "set it and forget it" basis. If a person has a more consistent system return temp, then it would be even easier to get the "right" setting for the limiting valve both to provide required boiler return protection and to maximize system flow. 

Wouldn't it be useful if a Termovar engineer chimed in and explained the reason for the design being what it is, if there is a reason, or to simply state that the design is not as good as it could be?


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