@derek-m thanks or checking in! The hot water situation is so much better with the pump off and is lasting longer and holding temperature in the tank- thank so much for the advice around this ! We are still having trouble with the hot water fluctuating in temperature upstairs despite turning off the isolation valve. The plumber has promised to come out and have a look- not sure when!!

I haven’t been able to balance the system yet- the electrician came out to switch the rooms round that were wrong and apparently had to re-wire something to do with the manifold and now we have no heating upstairs 🙄 hoping he’s going to come back tomorrow as not sure what he’s done!

once it’s stored I am definitely going to follow your advice and try and balance the rooms and get the weather compensation sorted 👍🏻

Posted by: @curlykatie

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@derek-m thanks or checking in! The hot water situation is so much better with the pump off and is lasting longer and holding temperature in the tank- thank so much for the advice around this ! We are still having trouble with the hot water fluctuating in temperature upstairs despite turning off the isolation valve. The plumber has promised to come out and have a look- not sure when!!

I haven’t been able to balance the system yet- the electrician came out to switch the rooms round that were wrong and apparently had to re-wire something to do with the manifold and now we have no heating upstairs 🙄 hoping he’s going to come back tomorrow as not sure what he’s done!

once it’s stored I am definitely going to follow your advice and try and balance the rooms and get the weather compensation sorted 👍🏻

I often wonder where people are being trained these days, assuming that they are being trained at all.

I can't say for certain, since I don't know exactly how your system was wired, and how many thermostats you have, but if there is one thermostat for each solenoid valve on your UFH system, then it should have just been a matter of testing which thermostat operates which solenoid. Once that relationship has been established, it should then merely be a matter of moving the solenoids that are installed on the wrong valves, to the correct valves. Assuming that there is sufficient spare wire to accommodate the move, there would be no reason to disconnect any of the wires. Simples. 😋 

@derek-m I know! I’ve no idea what he’s done! Hoping he’s coming tomorrow as the temp is really dropping this week!!

I’ll update once we’re sorted 👍🏻

@curlykatie my experience with troubleshooting my own heating system is that is really important for you the homeowner to know what does what, unless you are minded to take total "trust the guy I'm paying to sort all of it" approach. I'd suggest you try to draw yourself a diagram , of the water piping, and the wiring. won't bore you with the details, but once I did that with my own system when I had hot water problems, it become obvious that an important wiring connection had been missed by the installers.

really glad to hear you've got your hot water cylinder stable now. that secondary circulation circuit would have been (effectively) using your hot water supply pipes to the taps etc as a continuously operating radiator, with the source of heat being the cylinder, so no surprise the cylinder temp was always going down. you ought to find your heating needs to be working a tiny bit more now (although probably not by enough to notice).

ref your upstairs hot water, did you say there was a difference in behaviour between a tap and bath in the same room? could you expand on that more? if there are thermostatic mixers they can misbehave, and if there are pressure imbalances water can sometimes go the wrong way (from cold side into hot side) through a mixer if the mixer misbehaves and there aren't check valves to prevent that misbehaviour (I know, I've had one do that).

@iancalderbank thanks very much for your reply! I feel like I know lots more about the system than the ‘experts’ thanks to the help on this forum! I’m not sure what the electrician has disconnected- basically the stats upstairs are calling for heat but are no longer communicating with the Midea control panel downstairs, and therefore, the ASHP does not come on!

makes sense with the secondary pump- out of interest are there any other options anyone is aware of to get the hot water upstairs quicker? It takes a while to come through and just mindful of wasting water!

with regards to the hot water upstairs, if I run the bath it is luke warm (even with tank temp 50), I then have to run the hot tap in the sink in  same room (which comes out freezing cold) in order to get the bath tap hot… bath tap has a mixer. It’s the same in the en-suite upstairs…

@curlykatie its an exact trade off between the two options: having a secondary DHW recirculation loop (means you get HW out the taps instantly) vs not having one and you have to run off however much cold water is in the hot pipe until the hot gets to you. you either waste/use energy on the recirculation (which is where you were until you turned off the circulation pump and shut its valves) , or you waste/use water on the run off as you are now. you pays your money and you takes your choice! other options for instant HW are instant direct electric powered water heaters installed at point of use, often the case in commercial premises, but that doesn't fit well with an ASHP driven cylinder , not efficient at all, nor is it normal or safe in a domestic bathroom - definitely not a recommendation!

and ref the electrician - thats what I meant. If you draw it all up yourself, it might be really obvious what isn't connected.

there  must be a something wrong with HW supply to upstairs given the behaviour your describing, that is far from normal, to need to draw the cold pressure out of the tap in order to  leave enough hot pressure to get through to the bath. are you in a position to find the pipework to the upstairs outlets and draw a diagram where it goes / comes from, and work out which leg/ branch is goes hot/cold under what conditions? do you have isolation valves on the bath and tap that you can get to? or are you leaving all that to a plumber? It might be the case that solving the plumbing issue for upstairs reduces the amount of run-off that you need to do, but you will always have some, as do pretty much all of the households that don't have secondary DHW recirculation.

@curlykatie

Do you have any form of pressure reducing valve on the cold water supply to your hot water cylinder?

If you have mixer taps on your bath and the cold water pressure is greater than the hot water pressure, this could be part of the problem. The other thing to try is to push the mixer valve over to the hot water only side and see if that makes any difference.

@derek-m I am not sure if there’s a pressure reducing valve to the hot water cylinder… where would I find this?

@iancalderbank I’ll have a look at the wiring and see what I can work out. With regards to the electrician and plumber, it’s a new build so I’m at least not ah img to pay and feel like they should be the ones to sort it all out… I’m definitely going to work to learn more about the system though as they don’t seem very reliable!!

I’ll have a look when I get home later to see if I can access the isolation valves and have a bit of a play! 

Posted by: @curlykatie

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@derek-m I am not sure if there’s a pressure reducing valve to the hot water cylinder… where would I find this?

 

I'm not saying that there is a pressure reducing valve installed, but if there is then it should be located somewhere on the cold water feed pipe going into the lower section of the hot water cylinder. Ask your plumber.

Your mixer taps will have both a hot water and cold water feed pipes, each of which should have a small isolation valve, so that the mixer valve can be replaced without draining down the system. By slightly closing the isolation valve on the cold water feed, it should be possible to balance the hot and cold water flow rates. Your plumber should know how to do this. 🙄 

@curlykatie  you're looking in the mains water  (not central heating) pipework  around the cylinder for something like this (if there is one). its job is to reduce the incoming mains pressure to a safe level that the cylinder is certified for, and dump over-pressure water safely to outside.

if plumbed correctly it  makes the pressure on the hot and cold distribution pipes in your house the same. If you do have one, take pics / draw diagram of what pipes go out of which ports (and where those pipes go). I get what you mean about new build and wanting them to pay - but in my experience in many areas like this, it can be very helpful to say "here, I've already worked it out to 90% confidence its this >>>>" rather than "its broke, please fix it" - the latter may result in all manner of blind-alley / made-it-worse experiments.

as an experiment  / as a short term fix to get a hot bath ,you may simply be able to turn off the isolating valve  on the cold feed to the bath. But, the mixer may shut down if it has no cold feed - it depends.  if that happens and you partially close the isolator , it will act as a poor-mans pressure reducer, mitigating the issue and you might get a more-or-less working bath mixer.

but for root cause, you need the plumber to figure out why the pressure levels are totally mismatched upstairs and then correct it.

@iancalderbank

@derek-m thank you both for your help. I followed the pipe which comes from the bottom And says ‘cold’ so I am assume this is the mains feed for the DHW. If I follow this up I think I have found the pressure relieving valve- attached a pic!

I am not sure how to access the taps for both the bath and shower isolation valve- have attached a pic! At least when I speak with the plumber I can go to him with an idea of what it might be 👍🏻