Radiant in floor heat

[aLf]

Has anyone installed a good thermostat for in-floor radiant heat?  The new system will have many zones and I'm interested in a complete (handles all) type of therm that hopefully is wifi based. 

[stusviews]

Do you want/require integration with an ISY?

[larryllix]

Has anyone installed a good thermostat for in-floor radiant heat?  The new system will have many zones and I'm interested in a complete (handles all) type of therm that hopefully is wifi based. 

A good in-floor radiant heat thermostat will have some analogue aspects to it's output. This can also bed one with a mixer control panel with outdoor reset capabilities, that a simpler thermostat controls.

 

Simple bang-bang thermostat control systems do not function well in milder weather seasons. Just after your system spends hours heating you high thermal mass concrete slab or flooring structure the sun will come out and you will need to turn on the A/C.

Sensing of the slab and outdoor temperatures is necessary for predicting the needs of gentle temperature regulation hours ahead.

 

My basement slab gets set back a few degrees at 5 PM for the midnight bedtime and set back to normal at 5 AM for decent heating by 9-10am. I also run a minimum temperature in the summer while my A/C is running but I also have chilling well water circulating through it so taking the chill off only stores heat for future hot water draw.

 

Yeah, it can get complicated. I have 5 zones using TekMar thermostats that talk to each other, share information and also talk to my mixing panels that proportion the hot and cold water using variable speed pumps. I would not try even a simplified version with rf or powerline communication techniques with hardwired watchdog units.

[aLf]

Yes, actually was going to integrate with ISY if possible.  I know that the recovery, etc. of radiant is long and that it pretty much is a set-it and forget.  Just wondered if anyone was using anything to monitor or adjust.  Sounds like there will be just about a zone per room.  That said, I can't imagine a way to control it otherwise.  Maybe a radiant guru out there can explain.

[larryllix]

Is this an already running system and you want to monitor it and do some smart ISY controls or are you starting from scratch?

[aLf]

Starting from scratch.  Everything is on the drawing board.  Break ground this summer.

[larryllix]

Starting from scratch.  Everything is on the drawing board.  Break ground this summer.

I installed in-floor slab heating in my basement and an air handler for the whole house using a hydronic coil. My systems are open loop as opposed to closed loop. Open loop is not recommended by most but some very knowledgeable types still recommend it with a few caveats.

 

For an open system make sure your water is processes through filters to take out any grit and minerals. Even with a closed system will plug up your heat exchanger.  Do not use PEX-AL-PEX piping and do NOT use bronze fittings. Research "dezincification". There are many class action suits going on right now with almost every PEX manufacturer for removing hydronic systems. It has become a dirty business and many are getting hurt. No clear cause has ever been identified and there is much confusion and BS over it.

 

Do all your PEX loops in a double spiral method, ie. outside to inside and then reverse spiral back out to mix your temperatures evenly. Use smaller gaps for outside loops. I installed double concentric spiral loops in my larger room. If a loop ever becomes bad you have  back up loop in that room.

 

I used a cad system for my layout. I don't know how you would ever do a decent job without it. I set my snap tool to 6, 9 or 12 inches and laid out my piping and it worked like  a charm. This lined up with my concrete metal grid matrix for easy installing. When I was done I had a valve map to post by my manifolds.