Radiant Flooring over heating

tboehm

I have a home that is 3 years old in Alaska. All of a sudden I have multiple Zones where they are now heating to over the temp that they are set at. THis has never happened before. I have watched some of the valves opening and closing just fine, I have recently but new batteries in the thermostats. It seemed to be one zone first then another and now a third. I could use any thoughts or advice. It is very hard to get someone to come look as I’m somewhat remote.

tboehm

You may see some of the labels say glycol but it is water. That is just the stickers he had and the hole in the wall is from a old repair after installation. Thanks again for any thoughts or input. A little more info. My zones are real zones to the fact the some of my interior wall are insulated as well, 1 temp is set to 65 and it’s 71 another is set to 68 and it 71 and a third is set to 66 and it’s 68.

EdTheHeaterMan

Radiant floor heating can take some time to adjust to rapid outdoor temperature shifts. outside temp rises 25° and just after that the room temperature over shoots, that may be a normal thing. The outdoor temp does not normally do that very often. Is this a one time occurance, or is this starting to be a regular problem?

If it is turning into a regular problem, there may be a valve sticking. How are the lower temperatures regulated. Are there automatic mixing valves? Do you have motorized mixing valves? Do you use injection pump with high temperature on a primary loop and lower temp on a secondary? Is the entire radiant system direct to the boiler and the boiler runs at the low temperature (not recommended on cast iron boilers)? If it is the last choice, then how does the indirect water tank get high temperature? It could be a control issue, and there is probably nothing wrong with the thermostats.

tboehm

Ed. This seems to have happened all of a sudden. Never before have I seen it and there seems to be a domino effect. One zone then a few days later the others started. My bedroom has been set to 66 and has never fluctuated at all and now it’s 68. The other day it had got to 69.

EdTheHeaterMan

A You may have a mixing valve (or other mixing device) sending a higher temperature to the floor. The floor over heats over a long period of time then, by the time the thermostat is satisfied, the floor is hotter then designed and the over temperature takes over. no call for heat but there is so much extra heat that the room temp goes past the thermostat set point. eventually the room goes back to the thermostat setting and it happens elsewhere.

Does this sound like your situation?

B You have the over temperature and it stays at the over temperature until you lower the thermostat to correct the difference.

Does this sound like your situation?

If neither, then maybe you can explain in more detail what happens and what you do after it happens. Also what happens if you do nothing!

tboehm

A- I’m sure there is a mixing valve but not sure why all of a sudden that would cause the problems but it does seem to be a multi zone problem so it can’t be an individual zone valve or thermostat.

B- I haven’t changed to touch the therms to mess with the temp in order to correct,

Not sure of what other info that I could describe about the situation.

Zman

It looks like you have a thermostatic mixing valve with an Allen wrench hanging off the side behind the water heater. Is that connected to heating or DHW? Some pictures or a sketch of the piping in that area would help.

tboehm

jinbtown

Red is space heat mixing valve, blue is DHW mixing valve

Zman

The valve with the Allen wrench (red circle) is controlling the floor temp. What does the gauge below it read?

tboehm

ZMAN sorry just saw your question. Was gone for the holidays. Just checked and the system isn’t running and it’s at about 119 Deg. And again I now have woke up to the bedroom zone at 69 degrees and set to 66. I have gotten a thermal gun and finding different temps on the floor so it seems one of the loops isn’t working/operating flowing the same. So now I have this to investigate but I don’t see how this would allow the over run of temp. Especially as a new issue even if the dummy that installed the system didn’t measure/ensure matching run lengths is that is possible the issue.

Zman

The temp is only relevant if the system is running. Since you say the problem happens when you wake up, is it safe to assume the sun is not a factor?
My guess is that your supply temp is too high and the high mass of the slab is getting too hot before the t-stat can react. Your mixing may be failing or incorrectly set. Outdoor reset control would also help with this issue. A smart mixing valve like the Taco I-Series would be an easy retrofit.

tboehm

Well I just discovered my idiot contractor crossed lines on my 6 line manifold so I have 2 lines not working %$#%^(***@ !! 1 from the supply returning to the supply and 1 from the return returning to the return.