Advice needed on hydronic heating system - new construction

[Haystax]

Hello -

New to this forum, what a great resource!

I am building a new home for myself and will be using in-floor hydronic heat as the primary heat source. Wood stove as secondary heat. Mod-con propane fired boiler with indirect tank is the plan. Primary/secondary type system.

ICF basement + single story ranch, std. 2x6 construction - 3500sf total heated space

Basement 6" slab was poured with Uponor hePex 1/2" tubing on 12" centers, 6 loops in Uponor manifold likely one zone.

Main floor is all Warmboard radiant subfloor - 3 zones (although great room and kitchen will basically act as one) with beds and baths on individual t-stats -

I've done a heat loss with Uponor ADS software and had supply houses do a couple quick rundowns and a 110K mod-con is what we've settled on. My figures are around 70,000 with the ADS software.

Trying to get enough info to DIY the install, have the Siegenthaler and Holman books, trying to get time to read them thoroughly.

Main questions at this point:

1. What is the best method for determining the necessary water temps for the Warmboard vs 6" slab?

2. Based on these temps, is a 3 way mixing valve + zone circulator type system the best route to take?

3. Are most boilers of this type "smart" enough to figure out what temp to provide for the indirect when it calls for heat and then automatically lower the temp for the radiant zones?

4. Which is a better boiler - Triangle Tube Prestige, Weil-McClain, Knight or Buderus for a DIY installer/troubleshooter of above average mechanical aptitude?

Leaning towards Grundfos circs and controls and maybe even the Uponor controls and a TT boiler + Smart DHW tank. Have limited installer resources due to my remote location. Thank you for your time.

Craig

[furd]

I sure hope you insulated under that slab and provided a thermal break between the slab and the walls. If not you are going to be sorry.

I'll answer your questions to the best of my ability.

1. The temperature of the circulating water is going to be dependent upon what you use for the finished floor. Carpet will require a higher temperature than will ceramic tile and wood will likely be somewhere in between the others. The slab will have a much slower response than will the Warmboard. You do not want the finished floor to be much more than 80 to 85 degrees F. or you won't be able to stand on it for more than a minute or two. Generally circulating water temperatures of less than 100 degrees F. for the Warmboard and maybe as high as 110 degrees F. for the slab depending on how well the slab is insulated.

2. Yes.

3. I don't have the necessary information on the boilers. Others on this board will be able to help here.

4. DIY install will probably result in no warranty.

[rbeck]

the answer to #3 is yes. It will bypass the outdoor reset when you get a call for DHW and allow the water to heat the tank at 180f or whatever the high limit is set for for DHW. The heating and domestic temps are set different.

The only thing I disagree with that furd stated in error on was the warranty. A manufacturer MUST stand behind the warranty. If it ever goes to court it must be warranted. The most important thing to remember is you may not get warranty. Note I did not say get a warranty. The warranty covers manufacturers warranty only covers manufacturers defects. If it is an install issue or the install caused the problem it will not be covered whether installed by a contractor or a home owner.

[Haystax]

Thanks for the input -

Slab is insulated below, finished floor coverings will be marble tile, bamboo floating floor, and engineered flooring in basement.

I am aware of the 85* design parameter and will be going off of the Uponor ADS numbers to start.

I am not too concerned about the warranty, I doubt I would ever see a warranty claim pay off as rbeck stated. My location dictates that I install this myself as the only quote I have from a plumber is absolutely ridiculous - $5K for install alone, let alone high markup on materials.

Thanks for the replies, keep it coming!