I am having an ongoing discussion with my plumber about the installation of my ASHP system. Further to previous posts on BuildHub (and very helpful feedback) and a non-committal review by MCS following my complaint I am now looking for someone to review my system and advise where there are issues with installation and non-compliance with MCS or any other relevant standards.

 

I am between Bristol and Swindon.

 

Does anyone have any recommendations of any companies who would cover my area for this sort of review.

 

As always with BuildHub, I very much appreciate input from everyone!

Can't help with a name or company - but what appears to be the issue(s)?

Can't give you a name for your area either, but a few things will make any review quicker and cheaper.

Before anyone visits, pull together the MCS certificate, the room by room heat loss calculation, the design flow temperature, the emitter schedule showing each radiator's output at that flow temperature, the pipe sizes and the commissioning sheet. A lot of compliance problems show up on paper first: emitters too small for the design flow temp, no proper heat loss done, or a unit sized off a rule of thumb. If your system has a monitoring app, a week or two of flow temps, run times and electricity use tells a reviewer more than a one hour visit.

When you ring round, ask for an independent heating engineer or heat pump consultant who does design and commissioning reviews and isn't trying to sell you a replacement system. Ask them to report against MCS MIS 3005 so the findings line up with your complaint.

On the complaint side, if your installer was signed up to RECC or HIES as part of their MCS registration, that consumer code's dispute process can often go further than MCS itself, and an independent report gives it some teeth.

What are you actually seeing, high bills, cold rooms, short cycling or noise? That would help people here point you at the likely cause.

Thanks John and JP for your replies and some very helpful points there JP for finding someone to assess the system.

The issues with the system are partly set out in this thread https://forum.buildhub.org.uk/topic/43959-buffer-tank-hot-when-heating-mode-turned-off/

Potted History

Builder subcontracted local plumber. Local plumber confirmed that Daikin (through their Sustainable Home Centre which is the local plumbers' merchant) would be designing the system and to obtain the BUS an umbrella MCS company would sign the system off and do the BUS paperwork. Daikin SHC provided a design schematic of the system.

Once the system was installed I had some queries (mainly the sizing of the ASHP and why a buffer had been installed when it wasn't on the design) Daikin SHC turned round and said their design drawing was indicative and they weren't the designers (oh great I thought). When pushed further the plumber and Daikin ducked the issue by saying that as the system was signed off by the MCS company then it was all their responsibility and I would have to raise a complaint with MCS. I did that but in the period the complaint was being progressed MCS company has gone into administration and therefore MCS have stopped progressing their investigation.

The builder and plumber have said they will put things right if it is needed but at the moment is it me with my limited knowledge arguing with the plumber with their limited knowledge about what is correct/not correct with the installation. The conversation from their side has largely been that I have hot water and heating... so where is the problem.

Key Issues

No Design - nobody has designed the system so I am not sure what issues there might be in addition to the below.

Oversized ASHP - At the time of install Daikin calculated heat loss at just under 6kw but had no 6kw units available so provided a 9kW unit for the same price. I queried this and was shown their calculation/was assured that the 9kW unit was more efficent than the 6kW unit (which I assume had not allowance for cycling within the calc.). I am not convinced they took account of the MVHR correctly in that calculation either. In the last 12 months the flow temperature has not needed to be higher then the minimum setting of 25 degrees and on the coldest night last winter the unit still had periods where it didn't run due to inside room temperatures meeting the set point.

Buffer Tank - I query the need for it (as did others on the above post) and note that in the MCS3005 is cautions against their use.

Third Party Controls - the only thermostats are third party with no Daikin master, so modulation of the flow temperature isn't possible and cooling mode doesn't work through the thermostats

Isn't it an MCS requirement that the MCS company that's gone bust carried insurance for the situation you're in....flawed design??

22 hours ago, James1234 said:

The issues with the system are partly set out in this thread https://forum.buildhub.org.uk/topic/43959-buffer-tank-hot-when-heating-mode-turned-off/

I've just had a look through this thread to get an idea of the history. I am MCS certified and I'm fully Heat Geek Mastery trained too and actually based not too far from you in Bath.

Rather than go through the unfortunate contractual arrangements between the various parties, which doesn't help anyone right now, we need to pin down the facts.

When was your system actually commissioned and did you receive your installation pack from the MCS Umbrella? You should have had a contract directly with them. As @Dillsue says, in this pack you should have received an insurance backed warranty which must be for a minimum of 2 years for exactly these kinds of situations.

However, to take it forward to obviously need to know the defects and Daikin suggesting the system is okay is very unhelpful, if not entirely misleading.

From what I see in your photos, the installation does not comply with Building Regulations part L as none of the pipe has been insulated around your cylinder etc. That's just the start.

The claim that you have to have thermostatic control in each room to comply with building regulations represents a misunderstanding of the regulation when it comes to heating. Whilst building regs do state this, there are technical reasons why a system designer can design a system without any zones, using weather compensation that fully complies with the regs. The designer simply needs to provide the technical basis of the design decision and how it complies with the aim of the regulations.

The insulation job of your primary pipework from the heat pump to underground ducting is absolutely terrible. I'd want to check that the matt black insulation used beyond the short length of PE coated stuff is actually rated for outdoor use - I can't see what the print says but wonder if it's EPDM which is exterior grade or bog standard class O which isn't. But either way it's a terrible job.

22 hours ago, James1234 said:

No Design - nobody has designed the system so I am not sure what issues there might be in addition to the below.

The MCS design requirements are actually not that comprehensive when it comes to specifying the extent of a design. It only really says that the design has to show the calculated room by room heat loss and that the emitters are sized to counter the heat loss at specified minimum temperatures - indoor and outdoor ones. It doesn't include checking that the heat generator modulates sufficiently for annual average temperature, pipe sizing etc.
If you received a heat loss calculation to relevant standards BS EN 12831 that included an emitter schedule and dhw cylinder sizing calculation together with a MCS performance estimate, it's pretty much there. You also received a schematic from the manufacturer.
All this could be seen by MCS etc. as constituting a design in their eyes.

22 hours ago, James1234 said:

Oversized ASHP - At the time of install Daikin calculated heat loss at just under 6kw but had no 6kw units available so provided a 9kW unit for the same price. I queried this and was shown their calculation/was assured that the 9kW unit was more efficent than the 6kW unit (which I assume had not allowance for cycling within the calc.). I am not convinced they took account of the MVHR correctly in that calculation either. In the last 12 months the flow temperature has not needed to be higher then the minimum setting of 25 degrees and on the coldest night last winter the unit still had periods where it didn't run due to inside room temperatures meeting the set point.

This bit is key here because the 9kW unit is not the same immediate family as the 6kW. Daikin don't seem to publish minimum output data so it's difficult to know with certainty, but the performance measures on open energy monitor show that there is a big difference between the two when it comes to minimum modulation. The 6kW is 1.408kW and the 9kW 4.03kW. Assuming your newbuild is well insulated, a minimum modulation of 4kW if the calculated heat loss of just under 6kW was correct, means you're bouncing off minimum modulation for most of the year. However, if your heat loss was just under 6kW I'd question if the 6kW unit was the right choice in the first place due to potential drop off at your outdoor design temperature.

Do you have the recommendation/advice from Daikin in writing, or from anyone else about the 9kW unit? And do you have anything that states the 6kW unit does actually produce the required heat at your design temperature?

23 hours ago, James1234 said:

Buffer Tank - I query the need for it (as did others on the above post) and note that in the MCS3005 is cautions against their use.

Ironically, this may be your saving grace here, if the 9kW unit is bouncing off minimum modulation, whatever the distortion there might be with the rest of the system.

23 hours ago, James1234 said:

Third Party Controls - the only thermostats are third party with no Daikin master, so modulation of the flow temperature isn't possible and cooling mode doesn't work through the thermostats

For optimisation, yes this is rubbish. There should really be a Daikin master and the system should be running on weather compensation.

What does the usage data look like after a year of use? Do you have you COP/SCOP figures available.

The good thing in all this is that the builder and plumber have said they'll put things right if needed.

Beyond these things, it really depends on what you want in terms of resolution - do you want the existing system refined and optimised or are you looking to go the whole way and try to force a change of heat pump and then a subsequent system modification to suit?

Edited just now1 min by SimonD