Under floor heating manifolds

[John.g]

You can set the boiler flow temperature set point (target temperature),the UFH flow temperature and the individual loop flowrates, the boiler flowrate is then dependent on these settings.

 

[Rick1980]

So I think I have got to the bottom of the issues and it was pretty obvious now when I think about it but its not something I ever thought to check.

The "plumber" that has installed the new boiler has piped the flow and the return the wrong way round into the existing central heating system. The flow from the boiler is very hot and then the manifold for the upstairs radiators heats the wrong way round with flow passing through the actuator valve the wrong way and that gets hot a long time after the return is up to temperature. Obviously the heating upstairs is working fine this way as it's not fighting against a pump trying to pump water in the wrong direction.

 

[John.g]

What kind of UFH loop flowrates and manifold flow and return temperatures are you getting now and is the UFH system working OK on its own without boiler cycling?

 

[Rick1980]

What kind of UFH loop flowrates and manifold flow and return temperatures are you getting now and is the UFH system working OK on its own without boiler cycling?

While it’s flowing it’s not generating any heat. I’ll swap the pipes over and then see how things look.

 

[Ric2013]

If you only have one thermostat, then it doesn't really matter too much what setting your pump is on as it won't have to adjust to varying flow rates as all zones will presumably be on or off at the same time (unless you in the habit of manually controlling the actuators?).

Of course, you don't want the pump running on the highest fixed speed and then have to 'strangle' the flow using the flow meters, but the lowest pressure PP or CP setting that will provide sufficient flow for all circuits will do. Just my ha'p'orth.

 

[Rick1980]

Over the weekend I swapped the flow and return to the central heating system and they now have working underfloor heating. It took a while to warm the slab up but now it all seems to be working nicely.

What sort of temperatures do people have as a fall back temp for UFH? I think now its proven it works fine we will look at changing the manifold for one with working flow meters and adding stats for each room.

If they had it all fitted they would know the loop lengths to then control the flow, they don't have this information as it was all fitted so does anyone have any idea how this could be worked out? I'm guessing they would need someone with some sort of thermal imaging equipment?.

 

[exedon2]

Back set temperature should be maximum of 4C below desired temperature..

 

[ShaunCorbs]

Tbh around the 18 mark you can go lower but will effect heat up time etc