Wet Underfloor heating on radiator circuit help

[hwg10iar]

Hi all

Long winded question so bare with me.

we are currently in the process of building an extension and basement conversion. We are installing wet underfloor heating in the new rear extension and part of the basement.

Now I know when installing Correctly to Combi boiler this will need 2 zone valves and wiring centre etc...

However ! I am Temporarily Going to connect my ufh Manifold to my current radiator circuit By tee-ing off my main flow and return. Now I know this will mean that the ufh will come on and the same time as my radiators which is not ideal. However my screed is booked in and I need the system up and running and pressure tested before screed goes down next week.

How would I get power to my UFH pump ? I want to hard wire it into the boiler so that when command is sent from my radiator thermostat the ufh comes on as well .
Is this possible?

I know it’s not ideal and not the correct way to efficiently install ufh however I will pay for a professional to change it over to zone valves on separate thermostats After my screed is laid and my ufh has been tested.

hope someone can help!

thanks

 

[oldbuffer]

1. Use a test pump like the Rothenberger RP50 to pressurise the floor pipework. Then no need to connect up and risk overheating screed.
2. Not my field, but I think you need to leave the pipework pressurised while the screed sets, and bring up to temperature very gradually.
3. Again, not my field, but UFH runs at lower temperature than radiators. You could crack the screed by overheating it.

 

[hwg10iar]

Oldbuffer thanks for the reply!

I need to check for leaks in the system hence the reason I was going to connect it up. What you are saying is just do the pressure test with no water and if the pressure stays then there are no leaks?
I understand the ufh runs at lower temp but I thought that’s what the mixing valve on the ufh does only allowing the correct temp of water into the system?

 

[muggles]

Do the pressure test with water - fill the UFH pipework with water then cap off one end and pressurise it with the pump. There's no need to pressurise the manifold, you're just checking the pipes which are going to be buried are leak free at this stage. Keep it under pressure while it's being screeded

 

[hwg10iar]

Muggles thanks very much for your help

 

[hwg10iar]

What fitting would I need to attach to the Underfloor heating pipe to the rothenburger Pressure tester considering it won’t be connected to manifold?

 

[muggles]

What size pipe is it?

 

[hwg10iar]

It’s 16mm hdpe

 

[dilalio]

Just connect it to the manifold and pressurise the lot... Easier that way (if you have the manifolds).

 

[hwg10iar]

And this is ok to do even if the manifolds are not connected the boiler ? I take it I just close the valves and pressurise it without it being connected to boiler ?

 

[dilalio]

And this is ok to do even if the manifolds are not connected the boiler ? I take it I just close the valves and pressurise it without it being connected to boiler ?

Yes. Just have the isolators to the flow and return connected to the manifold and turned off. You can then pressurise everything via a connection to the manifold that isn't for the UFH circuits. Either the flow/return or vent. Put a lever between manifold and pump, then you can isolate after pressurising and remove pump.