Anyone know anything about radiant floor heating systems?

[Lurch]

Bought a place up in the hills for a weekend getaway. It has a radiant floor heating system that seems to be a closed system yet it is has a cold water connection. Is that connection used to fill the system and that is all or does it serve another purpose? In other words can I shut that connection off and turn off the water in the winter just in case?

[SideShow Bob]

Shut it off in the winter and the water in the tubes will freeze, then you have big problems when they thaw and you turn the water back on.
Keep it running at least on a low setting when the temp is frigid and unoccupied.

[Lurch]

I'm going to leave the system running my question is can I shut off the water that is supplying it?

[newracer]

It may have an automatic fill but if it is a closed system I don't see why it would lose any water.

[Circuits]

radiant thermal heating is awesome when you have it, and it's working trouble-free. But it's not without its drawbacks.

You have to keep it running through winters, or drain it if it goes dormant, just like a sprinkler system, or it'll freeze and spring leaks. Nice, even heat in winters when you run it, but problematic, especially in a sale, because most people don't know how to care for or run subfloor thermal radiant heat systems.

[Lurch]

I plan on keeping it running but I'm worried about an extended power outage. I know you can run antifreeze in them but it will cut down on the efficiency but I really want to cut off the water supply to the system just incase.

I know the big snow melt systems run with antifreeze and don't turn on until the sensors detects moisture.

[MarkCO]

I've designed them, installed them and done a lot of failure analysis on them. I have never had a system I designed fail, and I don't use a make-up water system at all, including the one at my house. I am currently working on three (lawyers involved and all) where the tubing froze, likely because the make-up water system admitted water, but there was no glycol added. Now a premixed glycol feeder, on a large system is not a big deal. In any event, a closed system with an expansion tank is a better solution. Glycol in the system does not significantly reduce the efficiency and actually keeps the system in better shape overall.

Depending on the tubing type and encasement, some can freeze and not have any issues, but you still don 't want to risk it. If it was me, I would delete the water make-up, ensure the boiler and heating loop have pressure expansion and relief and call it good. If you have an alarm system, add a low temp alarm sensor for some added peace of mind.

[68Charger]

As MarkCO mentioned, make sure you have an expansion tank if you want to close the system... otherwise the pressure will rise with the temperature, and drop when it gets colder...

If I were to build one, it would be closed with glycol for freeze protection.

[Lurch]

It does have an expansion tank and I can shut off the make-up water supply essentially making it a closed system. I did find some antifreeze in the shed so I pulled some water from the system to test to see if it has any in it currently. The system is very small with only 2 zones heating a 650 sq ft concrete slab on grade.

[MarkCO]

Yep, that is small. Sounds like you are on the right path. If the slab edges are exposed, I'd insulate them.