Slab temperature??

[overdriv]

I'm getting ready to commission my slab heat in a day or two and I'm curious what others have set the min/max slab temp at in their thermostat settings?

I think I'll start with a room temp of 60*F, but would the slab temp be set the same??

Any advice would be appreciated.

 

[tdkkart]

Your slab temp will be a few degrees higher, how much higher depends on your heat loss. Mine ends up 3-5* higher depending on the outdoor condtions

 

[overdriv]

Your slab temp will be a few degrees higher, how much higher depends on your heat loss. Mine ends up 3-5* higher depending on the outdoor condtions

Do you have a slab sensor in your system? If so what did you set the min/max slab temp at. Not sure I understand what these settings are for.

 

[tdkkart]

I do not hav a slab tmp thermostat, just a dirt simple honeywell stat that controls a relay, which in turn controls the pump(s).

 

[KenB]

I also have a simple thermostat that uses the indoor garage air temperature to regulate the radiant floor heat. I'm curious about the purpose of a slab heat control.

Ken

 

[Addrock]

My slab 63 (max) while the system is running. My system is ultra simple by design.

 

[Dkramer]

I also have a simple thermostat that uses the indoor garage air temperature to regulate the radiant floor heat. I'm curious about the purpose of a slab heat control.

Ken

The purpose of a slab sensor incorporated with a room thermostat is to limit the max. and min. temperatures of the slab regardless of room temperature. So if you have the room stat set for say 65 degrees and it is 55 in the room but the slab sensor max setting is 90 degrees and it is at that temp, no heat will be supplied to the slab. Normally if you are using a water temp control with reset, or are running mild water temps, you don't need a slab sensor.

 

[jayoldschool]

You should tilt that stat so you can drop the temp below the stat minimum. I keep mine set very low, but nothing freezes. Warm enough to work out there in a sweatshirt, and this is at -15F outdoor temps. This will also save you a LOT in heating costs.

 

[CARS]

My room target temp is 64. I have the floor sensor maximum set at 73. I think the minimum floor temp is 68.

Been playing with the settings for the last 5 years. I don't really know what the Tekmar thermostat does. Why regulate the slab when your goal is to achieve a certain room temp??

 

[Dkramer]

...........Why regulate the slab when your goal is to achieve a certain room temp??

If you are running warmer water than you want your slab to get, or, so your slab doesn't get to cold, meaning shorter recovery time.

 

[CARS]

If you are running warmer water than you want your slab to get, or, so your slab doesn't get to cold, meaning shorter recovery time.

Isn't that why I have a mixing valve?? So I temper the water going into the slab??

I'm sure you are right, but I have a more complex system. I have Rads in the office/bathroom and water to air exchangers in an old part of the building. The in-floor is just in the new addition. So the boilers high cut-off is 180 to satisfy the rads and the mixing valve is tempering it down to 95 at the supply manifold.

(nothing I do is simple around here )

 

[Dkramer]

Isn't that why I have a mixing valve?? So I temper the water going into the slab??

I'm sure you are right, but I have a more complex system. I have Rads in the office/bathroom and water to air exchangers in an old part of the building. The in-floor is just in the new addition. So the boilers high cut-off is 180 to satisfy the rads and the mixing valve is tempering it down to 95 at the supply manifold.

(nothing I do is simple around here )

Yes that is why you have a mixing valve. I've only used a slab sensor on one job that was heated by fan coils but had loops in the concrete floor to keep it warm for bare feet. If it were me, I'd set the min. to 55 or so and the max to 100. Or I would disable the slab sensor portion if the stat allowed that.

 

[CARS]

Thanks for the suggestion. I will turn the sensor off for the next couple months and compare from the last couple. I have an hour meter on the boiler and keep a log with the hours and LP %.

(don't tell the plumbing and heating guy, but I really should have gone with someone other than the local guy. After reading about what these systems are capable of, my 5 year old system was designed/built like a 20 year old system)