PeterW

Should do but wonder if no cylinder stat..? Only way is to not allow the programmes to clash.

That will be a change to planning so you will probably need to apply for a non material amendment.

Mrs Miggins doesn’t care. She just turns the knob on the front of the thermostat and the temperature increases. So if you don’t understand the controller, why confuse yourself further with understanding the complex interactions between the external thermostat and the internal controls ..?? Power curves, weather compensation and all that is set and forget by the installer. It’s why those menus have passcodes that only service engineers know ..!!

How close to the boiler ..? All 22/28mm pipe ..?

Main internal unit installation manual (boiler as you call it) https://www.vaillant.co.uk/downloads/aproducts/renewables-1/arotherm-split-1/arotherm-split-manual-hydraulic-unit-1456697.pdf Outdoor unit installation in 6 languages here https://www.vaillant.co.uk/downloads/aproducts/renewables-1/arotherm-split-1/arotherm-split-manual-outdoor-unit-1456698.pdf Interesting it has a “Quiet Mode” so next time Vaillant are there get them to enable it

yes - basically the pumps have a power curve where they work the delta out between available heat in the outside air, required heat for the house (delta between current temperature and desired temperature) and then depending on the curve, it puts the correct amount of power into the compressor. You do not want full power all the time into the heating otherwise you will massively overshoot the target temperature. To give you a simple analogy. You want a pan of barely simmering water to poach an egg. Put a pan on the stove and you turn the power up to 6 (assume 1-6) and it will come to a fast boil very quickly but if you put an egg in it, you’re going to ruin it. So you only put it onto 3, and it comes to a bare simmer but slowly. And you don’t overshoot the temperature you want. Perfect poached egg. If you want to know how it all works - here’s the manual for the weather compensation system. https://www.vaillant.co.uk/downloads/aproducts/controls/vrc-5/vrc-700f-installation-instructions-0020237057-00-1043324.pdf

Yeh I think the lower resistance of the coil (what floor is it on ..?) will offer less resistance than the rad circuits.

Fine.

No idea as it’s proprietary to Vaillant how they do it. But expect it changes the heat curves and the power input. 20-20.5 is too close for it to dump a lot of heat in - as I said, turn it up ..!!

Mid position means the water will take the route is least resistance. So the coil is most likely as the resistance on a coil is very low hence the balance valve to increase pressure on the rad circuits. Volume of water in the rad circuit will be far more than the DHW so will still prioritise the tank in effect.

It’s making sure it doesn’t over shoot the 20.5 you’ve set. 20-20.5 is very fine hysteresis so the unit will slow down. Put it to 22c and see what happens.

Just use countersunk 7.5 concrete screws as they are easy and don’t get in the way.

4x3 wall plates are for stiffness as well as build up so if that is spec then why change ..? I use concrete screws to hold down wall plates and 140mm are fine for that purpose.

No but for the price of a roll of aluminum tape it’s worth it ..!

Better choice are these as they are pan head so sit better and also should fit through the holes in the straps without drilling. https://www.screwfix.com/p/easydrive-pan-concrete-screws-6-x-60mm-100-pack/9665r What sort of blocks have you got ..?

So he’s screwed then as of the heating goes to the MPV as priority then he’s got a pair of 2 ports right behind it ..... Diverter it is then ..! I recon that lazy mid position set up won’t be helping circulation on the single circuit.

Really low spec units that have a 1.5 uValue and only have 3mm glass on the inside pane and are not toughened. Made in Poland from memory and get rebadged by a number of importers.

Fixed to EPS..??

Whole thread running about it here.

Google search https://www.ebay.co.uk/itm/323727186720

Complete is as per completion for building regulations purposes. Therefore has signed off and tested certificates to meet the building regulations. Also starts your VAT reclaim window ticking potentially.

You need a completed build SAP EPC certificate for the house. That’s what the installer needs. If you aren’t going to be complete before 31st March then you’re not going to be able in reality to get one.

Someone said the bora is about £2800 or so I think ..??

Black Limestone can be as good if not better than slate and isn’t expensive at all.

No because you can’t do an as built until it is complete ..? And you’re not complete ..?? And the ASHP will show as electric heating (ASHP) not pellet boiler to get your RHI for the ASHP..!! So if they do it “as is” then your claim for RHI will fail... You old SAP will be the DER/TER design one, the new one will be your complete one. There is a difference ..!!