Mixing Valve Question

[Green Mtn Boy]

I'm trying to complete the installation of My Tarm Solo 60 and had a question about how I should mix the water for radiant application. I'm tying the wood boiler into an existing oil system but It was not installed properly back 20 years ago. The "mixing valve" they used was a line from the return manifold to the supply manifold with a balancing valve to adjust the supply temp. This doesn't work very well as you can imagine. Before I cut in to the existing boiler I was wondering how the majority of people mix the temp of the supply water. I used an injection control with a variable speed pump on my Solo 30 but that was at my house. This is in a 60 x 80 shop so the injection route seems a little over kill. The mixing valve would need handle the 200,000 btu load from the Solo 60. Any advise would be great.

 

[oldmilwaukee]

I am by no means an expert - or even an accomplished novice. But for better or worse, I chose an Honeywell MX 129 mixing valve for my Tarm 40 installation (I am about 2 weeks away from finishing the installation?). I have 4000 feet of 1/2" pex in my house, stapled under hardwood floors with aluminum plates, arranged in 18 loops on 4 different manifolds. With the exception of an Indirect DHW Heater, I'm going to try and push all of the BTUs from the tarm through radiant floors. Take a look at that valve. It has a Cv of 13 or better if I remember correctly. The ports are 1 1/2" diameter. Its a hefty piece of brass, with a hefty price, but it was the simplest solution that I thought I could implement. (short of the manually set ball valves that you mention, which would have been the cheap way out).