PeterW

Go out through the roof…? MVHR would be your friend here as you can put multiple extract points on a single plenum and fan unit. Was this not planned into BRegs submission ..?

Neither are monoblock so you have the internal units to contend with. I think the Hitachi has secondary heating in the internal unit as it claims 80°C but only has R-134a refrigerant which maxes out before then.

Was that one of the IP-rated switches ..? I’ve not had any fail for 2 years so interested as to the life.

From memory they are about 250mm

So why not use the standard UFH manifold and the Wunda automatic balancing valves ..? They just need a 230v supply and they balance to delta 7°C difference and are about £20 each. Then a cheap thermostat in the room - wired or wireless , and you can flow to a zone or even individual rads.

Don’t forget an unvented cylinder needs all the fun of discharge pipe work etc. if you have the space, and the water pressure, then consider a thermal store as it doesn’t need any of the servicing etc. You will need to store at higher temperatures but no issue with that if it’s direct electric anyway.

Fact Check #1 - no you won’t, it is around 30% increase in output and many rads are already oversize so do the heat loss calculation first. Fact Check #2 - for Gas at 88% efficiency and Electricity at CoP 2.5 average (which is low) then it will be around 20% more. How insulated the house is is irrelevant when comparing heat input sources. If you have a big gas bill now, an ASHP wont reduce your heat demands. Fact Check #3 - modern units are around 52dB or less. Some it is near impossible to hear them from 4-5m away.

Yes - GRP but look crap in my opinion

Print your own - laminate it and stick it above the cabinet. Make it easy to read

This happens with towel rails. They don’t circulate properly as the flow goes the shortest route.

Well… that’s what we insist on ..! All blocks and bricks go to one side and are sorted before chucking anything in a skip. Halves of bricks and blocks get cleaned and re-used. Don’t forget, you also need back fill for soakaways so brick and block offcuts can always be used for that.

They have pretty cheap and nasty aluminium heat exchangers in them and a 2 year warranty as standard. For the money there are better boilers, and to get anything more than the 2 years you have to use a Vaillant installer.

You can use a latching or timer relay if you don’t want to use HA - this would do it. You can set the on time for as long as you want (10 mins etc) the do all the switches in parallel.

Why not sheet the windows ..?? Heavy poly and a staple gun and make some frames from battens ..? Get some dry working space plus allow trades to continue ..??

Which insulation are you planning on using as most of the standard ones are not UV stable for external use. The only guaranteed ones are foil wrapped semi rigid fibre, and Armaflex HT Solar, or Armaflex Tuffcoat (or similar) Nothing else has UV stability. You can buy coatings but they are usually £60-70 a tub and used on process pipework.

No NRV and a circuit plumbed badly and the “hot” water is being pulled from lower down the tank. My guess is the plumber piped the hot return into the bottom cold feed and not the return port on the cylinder. Without a non return valve all you will get is cold water. You’ll also be cooling the whole tank when the pump is running. photos will help

Yeh just read that. So is it mid position with no feed as ‘normal’, black is boost and grey super boost..?

Depends but some are just a dry contact that needs triggering - what does the unit installation guide say..?

Shelly 1 with a humidity sensor. Can also add any number of momentary switches (in parallel) and also switch from the phone / app etc for change of £30

UFH manifold pump will be pulling a subset of the HP flow as it will only take full hot flow when the temperature of the flow is required to be increased.

No - if this is a split unit then it will be a refrigerant link between inside and outside. My query is does that then run to the convectors as a refrigeration line or is there a heat exchanger internally that converts the refrigeration to heated/cooled water

Depends on the size and scale of the job tbh. Check that they have included waste (skips), VAT, materials, any preliminaries such as site security and toilets, and have a look for any “price sum” for things such as kitchens or bathrooms. @anna what is the project ..?

can these do cooling ..?

Paint any cut edges with D4 glue. You can always sand it off at a future date. Other option is paint all the cut edges/holes etc with floor paint as that’s good too. Any holes for screws etc you can fill with cheap body filler.

I would set it to 48°C, let the UFH blend off the tank and it will shorten the trigger points between the ASHP calls when it’s ramping down toward the UFH set point.