A Simple Thermostat with a Floor Sensor?

Cyclist77

Currently have a Tekmar 519 but wondering if anyone knows of a more simple thermostat that does not require going through the entire menu in order to adjust the setpoint? Wifi would be a plus but not a necessity.

Thanks

pecmsg

How often do you have to reset the temperature?

besteam

Most simple would be Honeywell t87N. Does not have wifi.

Cyclist77

I only adjust when we get these unexpected warm spells. Like yesterday it was 54f and it was 20f the day before.

Cyclist77

The Honeywell does not appear to have a floor sensor.

GGross

the intent of the 519 is to set a floor min and max, and use the up/down arrow to adjust the air temp. you shouldn't need to be adjusting the floor temp beyond initial setup for space heating. Your boiler, or mixing valve should control the supply temperature to the floor based on ODR to maintain comfort.

HydronicMike

If you’re getting that much uneven temperatures you should probably try to lower your reset curve, and that zones' supply water temperature.

In general, trying to control the room temperature via the slab sensor usually results in room temperature fluctuations.

For a slab sensor in my master bath, I’ll just temporarily switch it to 'Away' if I get unusually warm temps in the winter.

hot_rod

You really can't have it both ways.

If you want to maintain a specific "warm" floor temperature, it will continue to heat the room temperature, ambient, as long as ambient is lower than floor surface. Approximately 2 btu/ sq ft output for every degree difference.

If you want to maintain a specific ambient air temperature, the floor temperature will vary based on the load at any given time.

The floor sensor is used to set a not to exceed or not to drop below temperature.

So do you want warm floors, or a set, comfortable ambient temperature?

Cyclist77

We seem to have found that a certain floor temperature is quite comfortable. About 87f. But when we had the recent "warm spell" it jumped up to 56f for a few days I would have like to be able to reduce that floor temp.

And to be completely transparent the Tekmar 360 is not active as the hvac friend found it beyond his understanding and I am just manually adjusting the mixing valve. Would like to have someone assist and even contacted the Tekmar rep looking for a referral but no response.

So I continue my search as I am not capable to set it up. But our home is quite comfortable.

pecmsg

and how long do you think it will take to let that slab cool?

Cyclist77

No slab it is a staple up installation.

pecmsg

Its still not designed for fast changes. Slow and steady.

hot_rod

it is worth the time to dial in the tekmar, but if you like the 87f floor temperature that room will get warm, very warm with low load conditions.

Staple up is considered low mass radiant, 1-1/2” gypcrete is considered medium mass and 4” or thicker slabs are high mass. Radiant ceilings and walls are low mass also.

It doesn’t sound so much as a flywheel issue as just a high surface temperature condition?

80-82f is generally the slab surface you see recommended in design manuals.

Cyclist77

Bob, I agree that it will be worthwhile getting the Tekmar dialed in. But I recognize that I am not the one able to doing it. I will contact the local Tekmar rep again, after the Christmas holidays, and try to find a tech.

Perr_y32

If you want simple, look at basic radiant thermostats with a direct dial and floor sensor input. Brands like Honeywell and OJ make models where you turn a knob or press up and down to change the setpoint, no deep menus.

Most of them let you run floor sensor only or floor plus air limit, which is what people usually want. WiFi versions exist, but the non WiFi ones are the easiest to live with day to day.

Kaos

Many out there, for example Tekmar 561. Lot of them are meant for line voltage though, so something to check.

I think the better option is to properly configure your 519 to do limit control on floor temps (just min/max temp) and use a regular wifi thermostat for air temperature control. No need to have two devices that can control floor temps.

GroundUp

The 519 is about the simplest floor sensing stat there is. Floor temp does not dictate comfort; just set a minimum floor temp and then set the air temp where you want it and it'll stay comfortable all year regardless of outdoor temp if your reset curve is even close to correct.