Temp

If I've understood correctly it heats the store from say 60 to 70C in about an hour with no heating load. Power = Energy/Time = (4200 * 500 * 10) / (60 * 60) = 5.8KW I think I would be inclined to do an experiment and let the store go cold (say 30C). Then with nothing calling for heat fire up the boiler and measure more accurately how fast it heats up and redo the sums as it sounds like its down on rated power.

He might reply that it was zero rated already. Especially if the invoice didn't specify the percentage. Does the quote say anything?

I'd be tempted to leave it open. I think less likely to block and easier to clean it did.

Do you have any of the discussion in writing?

@PeterW might correct me but i think he was saying the same as me. Eg there are three cases depending on height of the wall.. If its tall enough go up 150mm as normal. If its marginal go up to the undercloak as per your drawing. If its too short make a hidden gutter.

Got any photos of that?

I can't comment on all of it but he probably did this when he found he couldn't get the joist into position (poor planning?). It's not elegant but if the joist is fixed to the wall I think its ok. I might be out of date but I think chemical anchor bolts are normally used for fixing wall plates to brickwork. They probably could be retrofitted. eg by drilling through the wall plate into the brick (not a mortar joint), injecting the adhesive and inserting lengths of threaded rod. When set washers and nuts added. See what others say. PS: I might question the lack of a padstone under the ends of the steel above the patio doors but its not always needed.

I think 150mm upstand is normally the minimum recommended. That would be 150mm above the tiles. If a hidden gutter is used (as @PeterW said) it would be 150mm above the bottom of the gutter which would be lower. Hidden gutters can work with zero height above the roof if the gutter is deep enough. Image from here. https://1stassociated.co.uk/box-gutter-sketch.asp If this is an existing roof I think the main issue is likely to be a rafter in the way (fixed to the wall).

Not all lenders recognise all warranties. The Council of Mortgage Lenders used to have a database. I think the CML is now part of UK Finance a new trade body. Perhaps suggest the buyer go back to his lender and ask if he can take out a PCC? Or try another lender?

Pure speculation but.. Perhaps if the pump is failing the controller thinks it needs a defrost cycle. If that involves pumping hot water from the system/buffer it seems reasonable it might generate a defrost circulation failure error. Perhaps it tries to do a defrost but because the pump is failing the flow temperature falls and it thinks its out of hot water to do the defrost. I'm making this up as I go along so happy to be corrected if this is wrong.

Our down pipes go straight into 110mm vertical drain pipe at ground level with a rubber boot seal/adaptor. No leaf traps anywhere and lots of trees. Get a lot of leaves in the gutters but the drains seem to cope with any that go down. Do the hedgehogs save you having to clean out the gutters or make it easier/harder?

So are they saying you need a nice big buffer tank full of hot water to defrost it when it ices up? Could "Buffer tank (is used)" mean "Buffer tank (is used up/cold)"?

Oops I miss read that as DEVICE circulation error whereas it says DEICE which is same as DEFROST.

Google found this but I don't know if this is a totally different model.. https://heidi-air-conditioning.co.uk/assets/downloads/user-manuals/panasonic-aquarea/End-user-guide-F-and-G-series-A2W_HR.pdf "H65 Defrost circulation error Reset once if reoccurring contact your local Panasonic installer, quoting fault code"

Approved Document L para 2.42 says.. "Reasonable provision should be made to limit heat losses from pipes in accordance with the Domestic Services Compliance Guide.".. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/697525/DBSCG_secure.pdf Not sure if that mandates insulation for hot water pipes as I've not read it.

Efficiency has many meanings. 100mm Rockwool Cavity Insulation Batt Thermal Conductivity: 0.037W/mK R-Value: 2.7m2K/W 100mm Celotex GA4000 PIR Insulation Board Thermal Conductivity: 0.022W/mK R-Value: 4.5m2K/W So I would expect.. 100mm Celotex to be equivalent to about 168mm Rockwool. or 60mm Celotex would do similar job to 100mm Rockwool. Your mileage may vary. Celotex is slightly harder to install without gaps as Rockwool is compliant but I think that's mainly an issue when fitted between studs rather than over ply.

It might also be possible to replace the relays if they have numbers on them.

Think the temperature sensors use edge connectors on the PCB so no white plastic connector required on the PCB ??? This one also looks pretty similar but I cant see any matching numbers.. https://heatingpartswarehouse.co.uk/product/grant-temp-control-pcb-mpcbs96/?gclid=CjwKCAiAt9z-BRBCEiwA_bWv-BpM0mzS3DI_vjhm4RO_cSiHXdoWQBZ81HHJ1jwGZz9wPVopieemaxoCa30QAvD_BwE Says.. "Suitable for the following boilers: Grant Combi V3, Grant Vortex Pro Condensing Combi (After Sept 08)"

The BCO was being subtle. He could have said "I'm going to fail your entire house for non compliance with part X paragraph Y subparagraph z and if you don't comply by my next visit I will be initiating enforcement action ". However BCO are generally more amicable than Planning Officers so instead he said "Those hot pipes might damage your Louis Vuitton" in the hope you might get the hint. Seems he failed ?

Ground staff looking after War graves in Europe told to return to the UK or face 50% pay cut.. https://www.thesun.co.uk/news/13467994/staff-world-war-graves-uk-50-per-cent-cut/ I think I would be checking my contract of employment and labour laws...

I don't think a home office is considered a "habitable space" but the work is probably a "material alteration". https://www.planningportal.co.uk/info/200130/common_projects/25/garage_conversion/2 https://www.planningportal.co.uk/info/200130/common_projects/56/working_from_home/2

Does it have to be inside the ASHP or could it be anywhere in the pipe run?

Welcome to the forum Matt. Sounds like an interesting project.

What are the rooms going to be used for? If these are going to be habitable rooms the whole thing needs to be properly designed to meet building regulations, particularly with regards to escape from fire.

If you are making valley soakers can you turn the 12" wide lead sideways to make them as wide as you like or would they be too short top to bottom?