2 thermostats, 4 temperatures system

Baldrick_2

OK, since I end up nowhere with no-thermostat system and wireless thermostats came up REALLY expensive (~$2,400 for 7 wireless senders, 2 receivers, some extra panels), I have to use what previous HVAC guy left available.

Which is 2 thermostat wires he planned for central air (there is secondary system in that house).

Since 1 wire is at first floor (slab) and second wire is at 2nd floor (underfloor w/ plates), I will use them for thermostat calls.

Here is a simplified system sketch:
http://img100.imageshack.us/img100/5076/tnh1yz7.jpg

Since there will be basically 2 zones with 2 different temperatures (and additional balancing among these zones) and I am feeding higher temp zone directly from boiler (at 155F), second zone (120F) needs some mixing.

Would You go with I-series setpoint mixing valve or regular 5000 series mixing/tempering valve?

Darrell

I have, and you can, fire as many different sub-systems as you'd like with a single t-stat by closing a relay, (Taco SR501), with a single thermostat. Keep the secondary wires clean with regard to polarity and they become the t-stat leads for as many mixing devices as you require. I have a house that functions very well with a several thousand square foot living room, with 4 different heat types, and a single thermostat. That Stat closes an SR01, which then operates various Taco Zone valves via several Taco ZVC's which in turn operate appropriate sides of two Doumix's. There is some underfloor granite, there is some underfloor carpet, there is some infloor/carpet and the 30' tall windows have a very classy looking commercial HW baseboard against them. All of the ODR's are set so that the floor is the primary heat until it max's out at about 15 degrees and then the baseboard, which had been circulating at close to ambient temperature begins to ramp up a fairly steep curve, and it very handily fills in the cold glass wall while giving the perception that the floor's are doing all the work.

So then, in this particular house, I have one Doumix that is fired on side A by any of three different relay's and side B by either of two different relay's. I'll save you alot of time...use one offboard transformer to power all of the different doumixes and ZVC's...polairity counts...and you'll go nuts trying to sort out all the onboard transformers. Be aware, however, that using an offboard transformer for the ZVC's bypasses the fuse...but I bet you can figure that out at Radioshck.

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