near boiler mixing control.

[taxidermist]

I was thinking of something like this for next year to keep the mixing temp just above 140*

http://www.pexsupply.com/Tekmar-712-1-1-4-Brass-3-Way-Mixing-Valve-4866000-p

http://www.pexsupply.com/Tekmar-153-Mixing-Setpoint-Control-Floating-Action-4798000-p

http://www.pexsupply.com/Tekmar-741-Actuating-Motor-for-34-Way-Mixing-Valves-5908000-p

Its a little $$$$$$ but its only money!


Rob

 

[bpirger]

I've only done my own installation, but I have found Tekmar stuff top notch. I use the 361 and 362 as my radiant controllers (and boiler control, DHW, etc.) For my new radiant loops, I found some controllers made by Tekmar for WeilMcClain on E-bay that were about 20% of the tekmar price....so you might be able to find something out there, made by tekmar, that is cheaper (and the same stuff!)

 

[jebatty]

Rough pricing for all 3 components is around $600. What your reasons for choosing a motorized mixing valve as opposed to a Danfoss or Termovar mixing valve?

 

[chuck172]

How would it be if you started out with the Tekmar 712 for $125. Manually adjusted it to your temperature setpoint.
Or you can get the Taco Delta T pump for $175. Set that up to lower your return temps to storage.

 

[Singed Eyebrows]

I was thinking of something like this for next year to keep the mixing temp just above 140*

http://www.pexsupply.com/Tekmar-712-1-1-4-Brass-3-Way-Mixing-Valve-4866000-p

http://www.pexsupply.com/Tekmar-153-Mixing-Setpoint-Control-Floating-Action-4798000-p

http://www.pexsupply.com/Tekmar-741-Actuating-Motor-for-34-Way-Mixing-Valves-5908000-p

Its a little $$$$$$ but its only money!


Rob

I wouldn't be without a loading unit on my boiler even though the pump is marginal. With that boiler a Lado 21 100 should work well. I'm not sure what the capacity of the Termovar LU from Bioheat is, Randy

 

[jebatty]

I'm having my first experience with a loading unit, the Lkacaso LK810 which was furnished with a Froling FHG-L50 (170,000 btuh). It came with a Grundfos UPS15-58 3 speed circulator. This is installed at Deep Portage. Storage is 1650 gallons, a 60" x 140" horizontal tank. We are still learning the best operation of the Froling with the loading unit, which together are a real hotrod of a boiler system. I am very impressed with the function of the loading unit and its ability to maintain a relatively consistent boiler return water temperature over a wide range of system return temperature water, and its ability to capture the end of burn heat from the Froling and move it to storage. It is too early for me to comment more until I understand better the operation of both in the Deep Portage system.

 

[taxidermist]

Rough pricing for all 3 components is around $600. What your reasons for choosing a motorized mixing valve as opposed to a Danfoss or Termovar mixing valve?

This would be in my boiler loop where the water circulates around the boiler over the Danfoss mixes with return water to keep above 140*. I always mess with the ball valve closing it as my return water temp rises. I wanted to use a loadingvalve but my boiler is 150' from my tanks so the pump on most LV are to small.

Rob

 

[Garth B]

i used a honeywell adjustable 1" thermostic valve and it has been working well so far, thought it was undersized at first but it turned out to be the pump setting. I like the honeywell more than the taco thermostatic valves. keeps my return at 140 perfectly without a balancing valve

 

[ewdudley]

I was thinking of something like this for next year to keep the mixing temp just above 140*

You might like the injection loop solution. It requires about $75 in controls and relays, plus three pumps and bunch of fittings. With salvage components it can be quite economical, and it performs very well, but it's a fair amount of work.

There's one pump that circulates from boiler supply to boiler return. Another pump injects into this loop intermittently to maintain return temperature at setpoint with a plus or minus 5 degF swing.

When supply temperature gets hot enough it means that return temperature from storage is hot, so then a third pump kicks in to maximize flow through the boiler so the boiler doesn't have to idle because of high supply temperatures. When the third pump kicks in the boiler reciruculation pump is turned off.

It's nice to be able to set the return temperature by pressing the up and down arrows a couple times either way, and when both pumps kick in you're looking at over 25 gpm with a pair of 007s, which will suck away over 125000 btu per hour with only a 10 degF temperature rise through the boiler.

The lonesome checkvalve is for power-outage heat dump to storage.

 

[afblue]

After reading "Modern Hydronic Heating" by John Siegenthaler, my choice of mixing control is Injection mixing. It seems to be working rather beautifully for my system. My Paxo and storage run in a loop independent of the house distribution, and the injection mixing line and return line "bridge" the boiler loop and distribution loop together, pulling heat from the boiler/storage loop when needed. The components are much cheaper that a mixing valve, motor and controller. The Tekmar 356 Injection mixing outdoor reset was $256, and a Grundfos 42-10 (equivalent to a Taco 007) was $75, and a $ 10 valve to fine tune. The controller with the outdoor reset adjusts the water temp based on the outside temp, so its a very gentle constant heat. not constant switching on an off.