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Problem with single zone ufh


Abbas

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Hello

i am new to the group. I have lived in my house for 8 years and recently had Vaillant arotherm plus fitted. Ashp works fine. Prior to that I had a ground source system.  The downstairs has ufh on 4 zones and I have radiators upstairs. The hallway used to get to desired temperature quickly in the past and it felt warm underfoot. However over past few months the hallway struggles to reach desired temperature whilst all three other zones are fine (living room, dining and kitchen). The main control unit is in the hallway and as a consequence the heat pump is working continuously as it never gets to desired room temp. The flow to the hallway seems a little cooler than the other threes zone pipes  (but that might be my imagination) but the return is definitely cold whilst the return from other three zones are warm. This suggests to me that there is a flow problem to the hallway. However I have had a plumber over who says there is flow and nothing more he can do. He said to me that I need to have a separate circulation pump for the ufh fitted and that would solve the flow issue to the hallway. I can’t see how it will help as flow to other zones is fine and it’s just the hallway that’s  the problem. I am at a loss what to do next. Any advice would be much appreciated. I attach a picture. The hallway manifold is 4th from left without actuator. 

45A70D61-2607-4AE8-91D8-1439D2B44C46.jpeg

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The middle 2 flow meters are black with crud. I doubt you can read a flow rate from them, let alone trust it.

 

I would swap the 2 black middle flow meters for the 2 spare unused ones on the right.  Then you will be able to see what the flow rate is.

 

I suspect your system needs a good flush to get all the crud out and replacing with clean water and inhibitor mixed in.

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1 hour ago, Abbas said:

He said to me that I need to have a separate circulation pump for the ufh fitted and that would solve the flow issue to the hallway. I can’t see how it will help as flow to other zones is fine and it’s just the hallway that’s  the problem


He is correct. You may find the Arotherm internal pump isn’t as powerful as the old GSHP pump so you’re getting less flow through the system and consequently less heat to zones.

 

That looks like a fairly old JG system so retrofitting a pump and blender to it would be a challenge however it does make it easy to modify and fit a new manifold and blender / pump set. 
 

As @ProDave says too - whilst it is all off, get the loops flushed properly as they look full of crud ..! I take it there is no mag filter in the system anywhere ..??

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10 minutes ago, ProDave said:

I suspect your system needs a good flush to get all the crud out and replacing with clean water and inhibitor mixed in.

manifold..thumb.png.cdf599a7c88328cf9500123686b9e4f6.png

All the flow meters look blocked. 

Agree with @ProDave, get this flushed, cleaned and then see where you are.

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No magna filter. I will try and get it all flushed out first and see if that helps. Do you think reducing flow to first three manifolds (first three from left) would improve flow to the hallway manifold which is the last manifold? Is it worth a try?

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