New Boiler Install - Tempering Valve Questions

[Clarkbug]

Hello All.

So after much reading and deliberation, I have decided that Im going to get myself a Varmebaronen boiler for use this winter. Lots of good info here on the site, and plenty of really great members that have let me pick their brains on all sorts of things.

My intention is to use the "PT1" piping scheme from the folks at Tarm. You can see that here: http://www.woodboilers.com/uploads/public/PT1.pdf

I have purchased the ECM control already from the folks at Cozy Heat, and one of the members here sent me the wiring schematic (it wasnt in the box o stuff with the controller). However, the one thing Im not sure of is the use of the TV-2 tempering valve in the above listed piping schematic.

Is this valve really necessary? I understand that it will help keep hot water flowing back to the zones instead of diluting the storage tanks, but is it something that is a noticeable difference? My heat emitters are all baseboard, so I will need relatively hot water.

Any input is appreciated before spending the few hundred bucks (Im guessing on a price here, I havent found a cost for it yet) on this valve?

Much thanks!

 

[NCPABill]

I'm sorry I'm no help, but I'm at the same stage as you.... and looking forward to the answer!

Good luck on your project,

Bill

 

[ewdudley]

Hello All.

So after much reading and deliberation, I have decided that Im going to get myself a Varmebaronen boiler for use this winter.

They sure appear to be an excellent choice, let us know later how it works out for you.

My intention is to use the "PT1" piping scheme from the folks at Tarm. You can see that here: http://www.woodboilers.com/uploads/public/PT1.pdf

Is DHW one of your zones?

I have purchased the ECM control already from the folks at Cozy Heat, and one of the members here sent me the wiring schematic (it wasnt in the box o stuff with the controller).

ECM as in an electronically commutated motor pump?

However, the one thing Im not sure of is the use of the TV-2 tempering valve in the above listed piping schematic.

Is this valve really necessary? I understand that it will help keep hot water flowing back to the zones instead of diluting the storage tanks, but is it something that is a noticeable difference? My heat emitters are all baseboard, so I will need relatively hot water.

Any input is appreciated before spending the few hundred bucks (Im guessing on a price here, I havent found a cost for it yet) on this valve?

You could get away without the diverting valve in normal operation. It's less than ideal but all it would mean is that as storage gets gradually less and less hot, the circs run more and more, and they accomplish less and less. Some zones might fail to maintain setpoint sooner in the storage depletion cycle than they would have if there had been a diverting valve to minimize storage mixing.

However once storage is depleted and if maybe the house has cooled off a little more than you would prefer, then excess flow from pump C-1 back into storage could really drag out the time it takes to get your baseboard heaters nice and hot to help turn the situation around. This would have the effect of putting heat into storage when you would prefer to make more immediate use of it.

You might be able to use a Taco 5000 valve in diverting configuration. It would perform the same function as the Termovar diverting valve, but it would only set you back $100. However the 5000 is a lot smaller valve. With a 25 degF deltaT a typical circ (e.g. 007) can only pull maybe 75000 btu per hour through a 5000 valve, depending on the rest of the circuit. This might be plenty for your situation or it might be out of the question.

Another alternative might be a Danfoss 140 degF boiler return valve set up in diverting configuration. If you shop around they can be had for $140, but $200 is more likely.

 

[flyingcow]

Can't be as technical, or helpful as above. But i have the TV-2, works very well. I installed the system per Tarms plans.

 

[Clarkbug]

Thanks for all the replies, and the "real world" experience.

Ill be sure to post my experiences with the Varm, along with pics of the setup/install along the way. Im hoping for good things this fall, but still working on getting some seasoned wood stockpiled. Doing it as funds allow, but I know time is important here.

DHW is not one of my zones currently, and Ill probably make another thread on that in the near future. Currently I have two zones of baseboard hot water, and Im going to have my installer add the valves/tees for a third to be added in the back part of my house. We currently have an electric hot water heater, and my thought was to set up a flat plate Hx off of the heater with two circ pumps. The pumps would be triggered by an aquastat in the HW heater, but would run through one that would only allow them to run if the storage tanks are hot. This way I wouldnt burn oil to heat the water. Ill put up a schematic sometime, when there is a rainy day to draw one up.

I take it back, its actually the EMC control from STSS (http://www.stsscoinc.com/Products.aspx) Sorry on the juxtaposition of letters. Really just some switching relays tied into an aquastat to allow my backup boiler to run when my storage is depleted.

Since Im not really comfy with making too many changes to the piping in my system, I guess I should just bite the bullet and get the tempering valve. I appreciate all of the technical write-up Eliot, and the ideas about alternative products to use. The local Tarm dealer was pretty good to deal with, so I dont mind giving him a call to get one. However, do you know there are any site sponsors that sell this valve independently that may offer a discount? I dont seem to be able to find any available on the interwebs.

 

[ewdudley]

Since Im not really comfy with making too many changes to the piping in my system, I guess I should just bite the bullet and get the tempering valve.

Probably the right way to go.

But keep in mind it is a diverting valve, not a tempering valve. And it serves a generic purpose, so don't let your friendly retailer use fear, uncertainty, and doubt to persuade you to spend some extraordinary amount for the 'right' valve.

And speaking of the right valve, the print shows a 6440 valve, which is a 72 degC/162 degF valve. This is probably guaranteed to be hot enough, but the lower you can go and still satisfy your heat demand the better your storage subsystem will perform. The 6340 version offers a 61degC / 142 degF valve, which would make more sense to me, even for a baseboard system.

The guts of both the Danfoss and Termovar valves can be changed out to change the temperature for the valve, so if you can't establish on paper what the right temperature is for your system it would be smart to make sure you can get either temperature guts and try the lower temperature first and then switch to the higher temperature in the unlikely event that the lower temperature can't keep up with demand.

Unless you're dead set on the PT1 design, now might be the time to step back and consider a design that would allow future upgrade to a subsystem that could provide variable system temperature under micro-controller control with outdoor reset, e.g., primary/secondary or hydraulic separator.

--ewd

 

[Clarkbug]

Ahhh yes, you are again correct. Thats me using the wrong lingo, which is a bad idea given all of the bits and pieces in these various systems.

I had also thought that the 160 seemed a bit high for running baseboard, and was thinking the 140 degree valve might be the way to go. Thanks for that vote of confidence in that direction!

Im not completely sold on the PT1 setup, but its something that I didnt think too many folks around here would have a problem installing, and it makes sense to my brain. Plus I was able to buy an off the shelf controller to make it all go, which is nice for the future of troubleshooting, especially since Im on the road a bit for travel, and if the heat goes out, Ill need someone local to try and fix it. I considered the idea of going primary/secondary, but it seemed like I was was going to start adding more pumps rather quickly, and I wasnt sure what the real benefit would be.

My understanding of the microtemp controller (Im assuming something like a four way valve with a servo connected to an OA temp sensor, right?) is that it would allow only the temp water out to the system that would offset the heat loss through the exterior of the building. This way you dont get the bang-bang control and the living space stays more comfortable. Does this also help with wood usage and boiler efficiency? I only ask because I know I need to spend money to repair my windows and add weather stripping, as well as some more insulation up in my attic. (Normally this would come first, but I have to stop the oil bills first.) I figure thats a better investment than a micro-controller, at least for now.

 

[ewdudley]

I considered the idea of going primary/secondary, but it seemed like I was was going to start adding more pumps rather quickly, and I wasnt sure what the real benefit would be.

To me primary/secondary or hydraulic separation is nice for keeping all the pumping functions independent of one another. While I was getting stuff together for my system I ended up with literally a bushel of good-as-new 007s off craigslist for next to nothing, so I guess it's possible my approach got skewed towards using a pump to attack any given problem.

But the diverter valve in the PT1 system is a great way of solving the main problem that pump mis-match can cause, namely unnecessary mixing of storage.

My understanding of the microtemp controller (Im assuming something like a four way valve with a servo connected to an OA temp sensor, right?) is that it would allow only the temp water out to the system that would offset the heat loss through the exterior of the building. This way you dont get the bang-bang control and the living space stays more comfortable. Does this also help with wood usage and boiler efficiency? I only ask because I know I need to spend money to repair my windows and add weather stripping, as well as some more insulation up in my attic. (Normally this would come first, but I have to stop the oil bills first.) I figure thats a better investment than a micro-controller, at least for now.

I think for a wood boiler setup an outdoor reset variable temperature subsystem would only serve to minimize return temperature to storage, so it wouldn't help at all with wood usage or boiler efficiency since what the boiler sees is determined by its return temperature control. There's no way outdoor reset would put money in your pocket faster than reducing infiltration and enhancing insulation.

 

[flyingcow]

My BIL installed my Tarm and storage. I just stood there and cleaned the fittings. But my BIL lives 200 miles south of me, he's a very knowledgeable boiler man. So we followed Tarms layout, with their parts. mainly because if i have problems(which i really haven't yet) I can call Bioheat up directly and trouble shoot. It was pricey, but there is no controller or processor involved. When I fire my boiler up, it will send 165 degree water to the baseboard in 40/45 minutes(190 in about 60 minutes). Once the house is satisfied it will heat the storage. Or do both at varying degrees. Neat little valves.

One nice thing my BIL did was install quite a few temp gauges in the lines. I told him to install the system it as he would his own. You can see how each main line is running for temp. (Quite entertaining with a couple of your buddies and a few beers.) My BIL's advice was to do this, mainly his rational was, you're spending a large amount of money already, and a few temp gauges will be of great value in determining possible problems and just to monitor the overall performance.

Good Luck. It's nice spending $700 on wood a year(plus sweat c/s/s the wood) vs $3500 for oil.

 

[Clarkbug]

I appreciate all of the assistance, and Im sure Ill be back for further information.

I think Ill get the diverting valve at 140, and stick with the bioheat piping scheme, just for simplicity. I think that I would consider a primary/secondary or more complex control system if I knew I would be home all winter long, but I would rather not have a service call in January wipe out a good portion of my cost savings for the year.

Temp gauges are something that Ill have to figure out where I want. From a previous post, I had mentioned that I was able to obtain three 220 gallon tanks that have two large tappings on the side (which I intend to use for the header piping) and two small ones on the top. One of these in each tank will get an air vent, and my thought is to perhaps put a thermometer in one of the three, maybe an aquastat in one of the others? I know more data is better, but I want to make sure its quality information that will be useful.

Any thoughts on where the most useful places to know temps are in a system?