Temp

Perhaos because CH loops can be dosed with corrosion inhibitors where as secondary loops can't. That might affect pump life but if you have already paid for it then I'd use it until it fails. Several ebay sellers appear to sell that pump as secondary loop pump but I can't find any info on an RS25/6 on the Wilo website.

I agree you don't need a full time project manager but it's essential that someone with good organisational skills is part of the team. That could be you, a builder, a project manager, a site foreman or just a good all round trade you can trust. That person should ideally visit the site first and last thing to make sure people are turning up on time and not disappearing early and make sure everyone has what they need for the next day or two. You want to avoid trades turning up then having to go off site to buy essential nails or whatever because it turns into an hour coffee break you are paying for. It would be easy to discover that nobody has ordered something or you are short on materials , find they are on 2 week lead times and then loose a good worker because they have nothing they can do in the meantime. These are project management skills.

Making sure these are consistent with any stages as the lender requires. Retain 5% or 10% of each stage for snagging.

Welcome to the forum. Telebeam works but its probably more expensive so perhaps only use if more traditional methods can't be used.

Are you tiling over the screed? If so consider forming expansion gaps where two areas of screed meet at doorways. Otherwise there is a chance of getting a curved crack that can propagate through the tile. With a straight expansion gap you can tile upto it or put a cill piece over it.

Guess I'm not awake tonight. Was up watching the sailing at 3am.

How did you let the water pressure off? Heating drain cock?

Possibly another here for $35 but design looks different.. https://www.tubularheater.de/instant-heater-for-dishwasher/57083347.html

Google found one that looks similar to mine here but its not much cheaper than a whole new assy from ebay.... https://ziperone.com/products/00000024678

The Bosch heater in our dishwasher is prone to failure due to quite minor scale... The heating element is printed onto the outside of a steel tube. What happens is that a thin layer of scale builds up on the inside of the tube and this insulates the heating element from the water causing it to overheat. You can see where a spot has "blown" and its always at the bottom where scale formsbon the inside. I've had thus happen twice. I now put a bottle of cheap vinegar in the machine every other week to try and prevent it happening.

They can't do the impossible.

Humm. @Ultima357 figures do appear to show an average COP of about 11.

It should be straight forward to measure. Input power is easy, output power needs the flow and return temperatures uplift and the flow rate. I wonder if very high COP occurs during over run at the end of a call for heat cycle

Im not sure I would install UFH without finding out. We have 80mm of PIR in our floor between battens and wish we had more.

Does it remove all Permitted development? What's the exact wording?

Just about any solution will have some sort of "upstand" requirement on a flat roof (including the sun tunnels).

Presumably you want each button to sound a different chime so you know which door to go to, and the three chime boxes are for coverage in different parts of the house? Quick google found this range can do that.. https://doorchimesuk.co.uk/catalog/product_info.php?products_id=629 That model supports lots of different wiring options including mains and built in transformers. The circuit below is just one possibility based on their option B using an external transformer and chimes in parallel. You would run two core cables for the push buttons and three core to the chimes all to a central location like the CU where the transformer and a junction box is located. You might consider running extra cores to the pushbuttons as spares or future use. https://doorchimesuk.co.uk/pdf/CROMA_230.pdf It says each chime box needs 12V at 0.5A so I'd use something like a 12V AC 2A transformer. With more time it might be possible to eliminate the external transformer using one of the other wiring options.

Perhaps look at a stranded CAT network cable?

Does it need to be a sun pipe? There are quite a lot of regular roof lights around. The key is to find a good installer as its important to get the upstand built correctly to the manufacturers spec so it doesn't leak. They can be made less than 150mm high which is the normal allowance before Planning Permission is needed. See page 38.. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/190910_Tech_Guide_for_publishing.pdf Source: https://toughenedglasssystems.co.uk/product/skylights-rooflights-1000-1000/?gclid=Cj0KCQiA4L2BBhCvARIsAO0SBdYDHw4pi1LTL9uE49WF2s7X-UEy1KGVPUxOO5Y4Yf-2WbykSDWT_r8aAtZUEALw_wcB

Welcome to the forum.

Time to sell shares in house builders?

Is there enough insulation in the floor for UFH?

Perhaps make sure he knows how to do lead work or get someone experienced to do that?

House too air tight? No air brick?

I Sounds like he only has one stat (a Nest) for whole house. So yes all loops are either on or off together. If the Nest controls the UFH loop pump and boiler then no need for loop actuators at all. If they are just used for balancing it makes sense for them to be powered up (eg open) all the time to avoid accidental recalibration cycles.