Nu-Heat UFH - Problems with some zones

[JFDIY]

2 hours ago, PeterW said:

3 hours ago, PickaxePete said:

Errr ... that mixer is back to front if those pipe isolators are correct as hot and cold

 

Found this image on nu-heats website.

 

 

 

[PeterW]

@JFDIY this worries me as if that fails it fails hot, so your boiler will dump 55-65°C water into the floor ... that’s about as bad as it can get, and it’s another reason I don’t like Nu-Heat (other than their ridiculous pricing ..!!)

[PickaxePete]

Having left this a couple of days to see if there is any difference, I can confirm that the pressure has risen to between 1 and 1.5bar on the manifold gauge, which is in-line with what is being shown on the expansion tank gauge, so I *think* the pressure is fine (for now).

 

I've still got zones not heating up - the kitchen zone is a good example.

• Supply pipe hot
• Actuator valve open (as far as I can tell)
• The return pipe is cold
• Floor in zone is cold

Any clues as to what I can do now?  I think my next step will be to switch the actuator head with a zone I know is working, see if that works.  If so, might be able to pin it down to the actuator.

 

Would the flow valves have any bearing on performance here?  Should I change these for new ones or check if the old ones are ok?

 

Lee

[ProDave]

17 minutes ago, PickaxePete said:

Any clues as to what I can do now?  I think my next step will be to switch the actuator head with a zone I know is working, see if that works.  If so, might be able to pin it down to the actuator.

 

Would the flow valves have any bearing on performance here?  Should I change these for new ones or check if the old ones are ok?

 

Lee

Just remove the actuator head, the pin should push out under spring pressure and that zone should be open for full flow. No need to swap the heads about.

 

About all you can do is turn off ALL other zones and see if the defective one is still running cold.

[PickaxePete]

On 13/01/2021 at 16:39, ProDave said:

Just remove the actuator head, the pin should push out under spring pressure and that zone should be open for full flow. No need to swap the heads about.

 

About all you can do is turn off ALL other zones and see if the defective one is still running cold.

 

Thanks for the input ProDave.

 

I'm at the stage where I've removed the actuator head and it's still not heating the zone.

 

I've ruled out:

• Airblock - have flushed the zone (or flushed to the best of my ability).
• Actuator - removing the head makes the zone fully open.  Still not working.
• Mixer valve - moving the thermostatic valve increases temp as expected.  Mixer is working.
• Pump - other zones are working ok, and I can detect (by feel) the pump operating at different speeds when chaning the settings (I, II or III)
• Pressure - manifold is sitting up at same pressure as the boiler pressure

I'm at a bit of a loss of what to try next.  I think I'll try cleaning / the flow valve on the weekend as that's literally the last component on this problem zone that I haven't checked.  I may have to bite the bullet and call a professional!  Shame, as the components and setup all seem to be easily user maintainable if you're well informed.

 

Any input always appreciated.

 

Lee

 

[JFDIY]

Swap the actuator from a working room, leave wired to the working room, crank heating up in working room, see if loop in suspect room gets hot. 

 

After that; Is it worth fitting new (or swapping from a known good loop) the flow meter on the hot side of manifold and the pin valve on the return side of manifold and see if the problem goes away or moves with the components?

 

Another consideration Is I wonder if you have the loop lengths of the problem circuits, or if you can see any numbers on the pipes to work out if they particularly long?

 

After that I think you may conceed that the pipe spacing is too wide, or heat loss in the room (or downward) is too great for the system as it stands?

 

That said what are the floor coverings? We used to have a big rug in our lounge, if you lifted it the floor was about 10*c hotter underneath it. Point is have you got a big insulating floor covering stopping the heat coming through?

 

Must be something fairly simple

[john0wingnut]

On 14/01/2021 at 19:10, PickaxePete said:

 

Thanks for the input ProDave.

 

I'm at the stage where I've removed the actuator head and it's still not heating the zone.

 

I've ruled out:

• Airblock - have flushed the zone (or flushed to the best of my ability).
• Actuator - removing the head makes the zone fully open.  Still not working.
• Mixer valve - moving the thermostatic valve increases temp as expected.  Mixer is working.
• Pump - other zones are working ok, and I can detect (by feel) the pump operating at different speeds when chaning the settings (I, II or III)
• Pressure - manifold is sitting up at same pressure as the boiler pressure

I'm at a bit of a loss of what to try next.  I think I'll try cleaning / the flow valve on the weekend as that's literally the last component on this problem zone that I haven't checked.  I may have to bite the bullet and call a professional!  Shame, as the components and setup all seem to be easily user maintainable if you're well informed.

 

Any input always appreciated.

 

Lee

 

 How did you get on with solving this?