Uneven flow at manifold

samdeluxjones

My Nibe heat pump UFH system is 7 years old now and I have noticed the downstairs is always warmer in wintertime when the heating is on.

I went looking this year and noticed the downstairs manifold had all the flow valves almost fully open and upstairs had them almost closed.

I opened up the upstairs and it made little difference, I then decreased all downstairs and the flow increased upstairs but only marginally in the 3 valves shown which is our hall & sitting room which is where we want it on the colder evenings.

The 3 kitchen when started flowing cleared the murky water but not on the hall and 2 living rooms.

Any idea what's causing this and how to get those 3 flowing correctly.

Actuators were never installed.

Thanks.

John.G

Is there a separate pump that feeds both manifolds from a buffer tank, if so, what make/model/mode&setting is it on?.

samdeluxjones

https://www.boards.ie/discussion/comment/121343610#Comment_121343610

No buffer tank, there are 2 external pumps, one for hot water circulation and the other coming off the cold water tank.

There is an expansion vessel on the heating circuit which probably hasn't been pressurised because I had to pressurise the cold water one myself to stop the pressure fluctuating.

What pressure should these be at roughly?

John.G

Don't know, but normally a pre charge pressure of 1.0bar and a filling pressure of 1.5bar for gas/oil fired systems.

samdeluxjones

Just checked and 1.8 bar so no shortage there..

Just spotted this pump inside the guts of the heat pump.

John.G

It seems to be set to speed 1 or thereabouts, try increasing it to 2 or 2.5 if its settable incrementally, if not you will feel a click at settings 1, 2 and 3, just set it to 2 initially.

samdeluxjones

https://www.boards.ie/discussion/comment/121360728#Comment_121360728

Have it set to 2 see how it goes.

When the heating is on it sounds like a washing machine gurgling at the back of the heat pump/manifold, is this normal do you know?

John.G

Could be if air in the manifold?

samdeluxjones

https://www.boards.ie/discussion/comment/121397462#Comment_121397462

Can they be bled? unvented system..

Without doing the power flushing.

captivo

Hey - nothing to add here really, but we have NIBE system as well with similar issues, i.e. warmer downstairs than upstairs.

So couple of questions

• Where is that pump located in the heat pump? I'd like to see what ours is set at.
• Also the water visible at our manifold is reasonably murky, is this a big issue? If so I guess the circuits would need to be flushed?

samdeluxjones

https://www.boards.ie/discussion/comment/121401329#Comment_121401329

At the back of the indoor machine/buffer tank mine is on the left hand side (facing the back) around chest height.

Almost all of our downstairs flow controls were wide open and up stairs almost closed. When I slowed down the downstairs and opened up the upstairs the murky water cleared out of the flow control optics as soon as the UFH pump kicked in. Our living room & kitchen are upstairs so now it seems to be heating properly since we moved in 7 years ago.