UFH Floor Probe Placement

[Spinny]

I have u/f heating pipes embedded in a 120mm concrete slab laid over 150mm PIR.

 

System is running controlled by Heatmiser with Neo air stat and Neohub.

The concrete slab is currently unfinished and is to have a layer of levelling compound poured to level out the concrete. Then latex and LVT floor.

 

I am thinking it may be a good idea to add one or two floor sensor temp probes. What is the best way to lay these given the concrete is already in place ?

 

Q1 Thought I could put them in the levelling compound ? (This will be up to 20mm thick in places)

 

Q2 Otherwise I would presumably have to cut a groove in the top of the concrete to lay them in ?

 

Q3 Do I have to put them inside some small diameter sleeve or conduit and where might I find this ?

 

Q4 How accurate are these things ?

My thinking was a probe or two might be used to help stop the floor going over temp and lifting the LVT. Current using just a Neo air stat, but I have a manual infrared temperature gun and concrete temp getting up to around 26C in places.

 

[JohnMo]

4 hours ago, Spinny said:

System is running controlled by Heatmiser with Neo air stat and Neohub.

Why - Computherm are way better, you just need to control on a single zone, pump controlled by thermostat.

 

Thick screed doesn't need remote inputs from work, it needs to run continuously to batch heat (4 to 12 hrs) depending outside temp and flow temp, or continuously at a low flow temp.

 

4 hours ago, Spinny said:

 

I am thinking it may be a good idea to add one or two floor sensor temp probes

Why what are they going to do? If your floors is getting to 26 your flow temp is way to high and you are trying to do things too quickly, without knowing anything about your house, suspect you flow temp should be in the 26 to 30 (continuous) or 35 (batch) range

 

With a 140mm floor thickness if you are getting hot, it has taken you 24 to 48 hrs to get there, you ain't stopping with a floor probe, way to late.

 

Example, my heat pump is set to a target flow temp of 35 degs, after 12 hrs of running it's flow temp is 33. Would take me another 12 hrs to reach the flow temp of 35. The floor surface temp when I stop heating is around 22-23. You have 50% more floor height to heat up.  Your floor will be super slow to do anything.

[SteamyTea]

5 hours ago, Spinny said:

How accurate are these things

As a general rule, accurate enough.

A quick way to improve accuracy is to use temperature anomalies rather than absolute values. anomaly 

 

T_measured - T_mean = T_anomaly 

 

That way any offset from the true temperature (accuracy) becomes irrelevant and any linear or non linear precision drifts is reduced.

To make it even better, false readings can be filtered out as they precision around the central tendency, or mean.