Max Mixing Valve Temp for Engineered Oak

[SanMan]

We have underfloor heating upstairs and this has been working fine until yesterday when the cold weather hit. Now it struggles to get to 18 degrees, having only last week managed room temperatures of up to 21 degrees with ease. 

 

I checked the manifold and noticed that the mixing valve was set at a mere 36 degrees. 

 

My UFH supplier says that I can turn the mixing valve up to 55 degrees if the room does not get warm enough at lower temperatures. The floor is engineered oak on Tuplex underlay (very low R value and recommended for UFH) and then directly on spreader plates. The floor itself is protected by a temperature probe immediately beneath the floor that stops the floor going to 27 degrees. 

 

I don’t understand how a higher mixing valve temp can really help if the floor temperature limiting probe always hits the brakes of the system. And is it really ok to use a mix of 55 degrees? 

 

Thanks. 

[gilesm]

What is the temperature of the actual floor?  A floor at 27C would be pretty hot, and should result in your air temperature easily reaching 21C.  So I would say it's a reasonable floor temp limiting probe temp.

 

Many engineered woods can go fairly high, but I'd  prefer to not go higher than 45C on the mixing valve, even if the supplier says it's ok.  Perhaps try 45 and see if you see a difference.

 

 

[JohnMo]

The other issue maybe you are just running the UFH for to shorter time, running longer may do the job without increasing the flow temp.