Helene

Thanks for the advice, happy to give it a try. Should I turn off the pump completely before opening or there's no risk? I see 4 screws on the cover, I guess it's as simple as that? Hopefully...

Thanks everyone for your help - if I wanted to involve my electrician, and with my little knowledge, what should I tell him exactly?

Hi Nick, I've only seen your message now and I still haven't addressed the issue (partly because I've been given a very high quote from a heat geek without having seen anything). When you say "the impact is severe for DHW", in what way? In my mind it's more likely to affect the performance of the heating. If it's not impacting this, I can't complain about more hot water!

I can't know for sure if it's new, as our melcloud wifi controler was only fitted in June, and this allows to see the data with some graphs, and it doesn't go back in time. As we didn't use much heating since, I couldn't notice any issue while the hot water was on but it might have been there from day 1 (a year ago) indeed. As it's not an option to get the installers back, do you suggest I get an electrician or a plumber in first? I think our plumber doesn't want to go anywhere near our heat pump as it can void mitsubishi warranty if he does something wrong... We're in Leeds so if anyone has any local recommendations... Also, what is the impact on heating performance? Is it costing much more, is it reducing the flow? Trying to see if it's an actual big deal or not. Thanks!

It is helpful thanks, though I think I'll definitely need someone to have a look. For a gas boiler it's quite easy, I would just need to get a gas certified plumber out, but for a heat pump it sounds more daunting. I've added two pictures, which I think are valves, do you know which one would be the one potentially related to the issue? As per the controller, I think it wasn't something major, just adding the wifi device so I don't think it changed anything.

Thank you. The heating isn't warm but we had this problem a few months ago (now solved just by changing the lever position). I only realised this new problem since we got the melcloud wifi controler installed. What do you think I should do?

Hello. I've noticed from our melcloud graphs that every time the heating is on, the DHW heats up too. Which I confirmed by touching the flow pipe going into to the cylinder. Is it normal? I'm worried it's affecting the performance of the system and costing us more than it should. We have a mitsubishi zubadan 14W and a unvented cylinder. Thanks in advance for any advice. N.B. the company who installed the system less than a year ago has folded so it's not an option to come back to them.

Hello, I would love to know how you got on with the cover since 2021, and if you had any issue. thanks.

A bit of an update - the boss of the company who sold us the ASHP came around (after bad reviews I left) and agreed that our loft K3 shouldn't have been installed off the 15mm pipe from the room underneath (my office, which is cold). It prevents both rooms from getting a decent flow. So they will reinstall the K3 off another part of the house with 22mm, and help balance the system too. I'll give an update once it's done. Thanks everyone for your inputs so far.

Here is video https://photos.app.goo.gl/8XUp77f5hGCiCPoj8 Hope it helps a bit more. Thanks

I will try to look more closely at the piping, but hard when I'm not used to any of it. maybe a video could help? Very good question - they were supposed to send an engineer two months ago, now it's radio silence - needless to say that I am appalled. I've just sent yet another email to inform them that I'm going to charge them for an engineer visit that I will arrange myself.

I'm unsure it's the case as there was no air for a while when I last bled them, it might be because I've balanced the rads again, changed speed pump, etc.

I hope a few of these pictures help, it's really hard to take a picture as there are pipes in the way. So you think potentially two pumps is over the top? In this case I would think my whole system would be flying but instead it seems feeble.

I tried to change the speed and the flow rate didn't increase indeed. The top floor K3 badly needed bleeding actually (again) - so I was hopeful it was going to sort everything but I still have the same issue. I need to take a picture of the pump, it's a Mitsubishi Zubadan 14Kw. Here is a picture of the system, not sure what these things are called Hopefully it's good enough. I'm puzzled about why one red pump is upside down - I'm sure there's a reason. But they don't seem to be at their maximum, at least one of them. It's definitely something I want to nail indeed. thank you

Very interesting - I did change the speed a month or so ago as it was making so much noise - but didn't notice a difference with the rads. I just wish I remembered if the original flow rate was 40 or the same as now, as I've turned the speed back up to maximum last night but the FR didn't increase at all. I'm wondering if the piping is simply not adequate... though the top K3 does work when the other rads are turned off - not sure what it indicates... I'm desperate for the installer to send an engineer but they ignore me...

I could give it a shot when temps get higher again... as it would cost a lot at the moment 😬

Thanks so what would be the reason to have a lower flow? wrong balancing? The former is hard as it's a big house and I think the circuits splits in various places, and I don't know where... and there are various radiator types... but worth trying again. I've done that at the beginning and coldest radiators worked perfectly well - just not when all the rads went back on.

It's been nearly 3 months I was leaving with it until the cold came back. So you didn't have to do anything and it balanced itself?

Thanks for asking, still not - it's getting slightly warmer but cold return flow... it feels like all the working rads are on the edge of (hot/completely cold) if I turn them down in the slightest so I wonder if it will even get balanced.

We did but bleeding it (although needed) didn't help - I think I'm starting to make progress now that I've identified which sides are flow pipes and return pipes... didn't help that I knew nothing about anything to start with and that the new rads were fitted the wrong way around.

It's good to know for the K3 as I always feel like it's not getting hot enough, or not entirely filled up. What does the wago connector do? Thanks

I have tried the following methods: - Turning the lockshield valve off gradually for the radiators getting hotter quicker - but it's proven really hard because the house is big, the circuit might be all over the place (due to house extension) and various radiator types (most are K2/K3 but a few a single convector or towel rails, the latter being the hardest in my opinion, and can strangely have a big impact) - Using thermometers to try to get a delta to 5-7 degrees - only realised that a lot of our lockshield valves and TRVs have been mixed up so I'm having to re-do it all, however with 16 radiators it feels like I'm going nowhere... it seems that doing that gave me 10 degrees different on the flow pipes of different radiators... so far from the 1-2 degrees difference. Thank you

The heat pump tells me that it's at 40 degrees (and it's what the curve is setup at for the relevant outside temperature) However, since writing this post, I think I realised that loads of our radiators have the lockshield valve and TRV valves mixed up - so I managed to get some radiators to the actual flow temp - however the system is still not balanced as many radiators are cold (their flow pipe is hot but the return pipe is cold)

Hi Gary, I don't have the Melcloud yet (they're waiting for wifi controller to get back in stock) but I have been monitoring thermistor readings etc - and it always looks fairly healthy. Example on a cold day 43 degrees flow and 38 degrees return. Since writing this post, I think I realised that loads of our radiators have the lockshield valve and TRV valves mixed up - so I managed to get some radiators to the actual flow temp - however the system is still not balanced as many radiators are cold (their flow pipe is hot but the return pipe is cold)... I am indeed starting to question the flow rate - how can this be addressed? The flow rate is around 32/33L ... how can I tell if it's good enough? To add some context, it's a big 4 bedroom house with loft so we have many radiators - and it's very hard to tell the piping circuit, especially given the house has been extended. Thank you

Apologies in advance as I'm far from an expert - hence why I'm seeking advice! We had a Mitsubishi Zubadan 14KW fitted in Oct 2023. It works really well in some rooms and others (definitely bigger and with higher heat loss) it's been challenging. I don't think the system is well balanced as our loft K3 rad doesn't get much heat at all - so I'm hoping an engineer will come and help after all our failed attempts at balancing the system. My question today is - if the heat pump flow temp is at 40 degrees - but I measure 33 degrees maximum on the hottest radiator's flow pipe.... shouldn't it get 40 degrees? (return pipe is around 23 degrees, but delta will depend on the radiators at the moment, I have as low at 2 degree delta on some radiators). Just wondering if some rooms struggle to heat up because the flow temp is too low to start with... Thank you