How to fill / purge an UFH loop with this set up.

V0X

Two of the bedroom loops on our upstairs underfloor heating manifold are not working / flowing. I wanted to refill them to remove any trapped air and it looked like a simple enough job.

1. Isolate the manifold
2. Isolate all loops except for the one to be purged / filled.
3. Connect hose to drain valve (pictured bottom right)
4. Connect cold water supply hose to fill valve.

The problem is I can not locate a fill valve which seems to be present on most other manifolds. The only other option would be to use the fill loop at the hot water tank unit but I have read not to use that for this purpose.

Any ideas? It is an Air 2 Water heat pump setup with an upstairs and downstairs manifold. Image of upstairs manifold attached.

halkar

Try removing actuators and check if pins stuck for those loops with no flow.

Is the water flowing from downstairs to upstairs? You may have filling valve there and you can work with that.

Looks like they put a pressure gauge where fill valve suppose to be. Not sure what was the purpose of it but its pointless there. You can try replacing it with drain valve similar to one you have at the return of the manifold. You need to isolate the manifold by closing flow and return valves on right and drain the water. Once manifold empty you can replace the gauge with another drain valve. You should be able to work on manifolds and loops independently.

V0X

Thanks for the reply. Appreciate it.

Good point I will remove the actuators and check them.

Yes it flows from downstairs to up. The downstairs manifold is a similar setup i.e no fill point on the flow section but there is a drain on the return. There is a cold water fill valve / filling loop downstairs at the hot water cylinder unit but all information online suggests not to use a fill loop as it is not suitable. I assume if I did use it I could not isolate the manifold and would have to leave the flow to the manifolds open.

I am wondering now if I could just add a fill valve to the flow section like you suggested but have it on the very end like in this image so I don't have to remove any gauges. Any issues with doing something like that do you think?

I'd like to know how the installers commissioned it in the first place!

halkar

That is how it should be for filling and draining. I am not sure why they put a pressure gauge on your one. It would be easy to fit one after isolating and draining the manifold in few minutes. If you can't do it you can get a plumber.

You can use your filling loop too but not ideal. You can close all loops leave the one you want to flush and run the water for few minutes until water flows steadily. If you want to do that it be better to open all loops and flush all. Looking at the stains on flow meters water may be very dirty. You will need to add suitable inhibitor if you flush all but not sure if it will be easy in your setup.

I also think your loops are not balanced. Not clearly visible from flow meters but I think water flowing too fast in your loops. I keep mines between 1 and 1.5 depending on the loop length by guessing from room size.

V0X

Took off actuators and the pins seemed to be seized. Lifted them up and down a few times with pliers and flow meters sprang back into action. Will pickup some spares and fit a fill valve. Cheers.