radiant thermostats

bill_8

has anybody used the dual sensing thermostats? ie air and floor temp? my finish floors will be a combo of tile and engineered wood. I'd like to use an outdoor reset with a motorized mixing valve...not quite sure how this ties in with the dual sensing thermostat...or if it's even needed.

RTI has some various piping strategies using mixing valves in their installation manual one of which is interesting. Each zone has its own manual mixing valve and then there is a master, motorized mixing valve (run by outdoor reset) for the zone manifold. This seems like it would work well. Some of my zones vary by 10000btu load (high ceilings vs bedroom with 8' ceilings) and show different water termperatures (hence mixing valves on each zone) based on zone heat load calcs. This is per RTI.

Running 3/8 tube with AL plates...used 1/2 tube in office last year and what a difference in installation ease the 3/8 is over the 1/2. Same btu's you just have to run shorter (hence, more) loops.

Chris Maderia

Radiant Therm

For starters, radiant heat does not heat air it heat objects. You have to remember there is very little if any convection happening and your air changes are alot less. Whether or not you have different floor surfaces are to some degree irrelevant depending on what the design (remember this is the water temp you need at 0 degrees) water temp is and the finished floor surface temp. I would recommend based on your application primary/secondary piping with constant circulation on your primary loop. Your motorized 3-way curve should be set based on your highest manifold temp (ie first manifold off primary loop) and your other manifolds can be mixed with just a proportional 3-way. You do not have to due a reverse return in this application as long as you put a circulator on your primary loop at the end. The primary loops water temp will always be changing based on out-door temp and your curve off that 1st manifold. To be honest if the heat loss is accurate and your curve is set right you don't even need a therm in the house. You can wire all your circs in series and utilize warm weather shut down to turn your
pumps on and off. Remember that for every btu that is leaving you are replacing it with one. With this piping application you have to remember that you are not always taking all the btus out of your boiler you are only taking the btus needed to satisfy that 1st highest temp with return water. I can fax you a piping and wiring diagram.

hr

Dual sensor stats

I have used the Danfoss MTDs, and also hav 4 of the new tekmar 510 installed. It is nice to be able to control the floor temperature in conjunction with the air temp. A great feature for summer season floor warming in bathrooms. The tekmar has setback features, two stage ability and some heat cool models. A clever little stat, with some involved programing instructions.

hot rod

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