MikeSharp01

Don't think so, looks like it is a standard design so its got to be a tuning issue. If you are right that the zone 2 flow is so high it cannot loose enough heat in the UFH then some other aspects don't make sense do they.

Welcome to THE forum for people like us! Take a look at this video - long but with more than enough detail to allow you to tackle it.

Yes and short cycling is symptom of low demand where the HP cannot modulate down far enough to make only the heat that is required.

Yep - that looks like the nub of it and it means that the two pumps (the primary loop & zone 2) are not balanced if they were everything coming in the top of the header would flow through the UFH to ensure this you need to get the UFH pump creating a slight negative pressure at the top of the header. From all this it looks like the flow rate capacity of the UFH is well out of whack with the primary circuit. Also your control table seems to suggest that the OUT3 controls both pump 3 and a 2 way valve and the *2 note indicates a ON/OFF valve somewhere. There is some good theory on the LLH - https://www.flexej.co.uk/what-is-a-low-loss-header/ which explains the various modes of operation and gives you a feel for the way the flow rates mingle and what happens in the header. Possible investigations / experimentation might be, in no particular order or with any analysis of consequences: Restrict the primary flow pump so the UFH can take all the flow or increase the zone two pump capacity somewhat. Not sure linking the two zones together will make any difference it will just hit the HP capacity too hard.

I am still worried about return flow from zone 1 when it is not active, this must be coming from somewhere and the only place it can come from is through zone 1 and that must be getting heat at the header but as this is not getting back to the header it must be quite a low flow which means that the pump, although not running is allowing some flow through, albeit very low. Is there a manual valve you can use to isolate zone 1 and observe then?

OK, thanks for the schematic, can you show us how the Salus valves are connected is it just as this: https://www.vpsunderfloorheating.co.uk/wp-content/uploads/2019/10/THB230-Quick-Guide-V008.pdf ?

No plan - no costing - no budget - no idea(s) - no good.

This is the big conundrum - basically in terms of cost it won't be worth it. It only becomes worth it when you factor in the cost / value balance to the planet by seeing your 'best decision possible' in that light. Sadly the general feeling that the planet can be 'saved' without cost to individuals has to be a misnomer and so we are all, the generations alive today anyway, going to have to 'pay' to sort this out and waiting for HMG to find a plan that makes the costs go away is like waiting for a unicorn to be born in Trafalgar square - there is not even a stable let alone a breeding pair! If you do a 'full cost' analysis you may well find that the RHI payments, which you / me / all of us are paying for through our taxes, and lower running cost might cover the differential cost between installing a new boiler and sticking with LPG - which won't get any cheaper in the medium / long term.

Sounds like a flow control problem - well it would. I would have thought you should be able to balance the zones out in any pattern you like through flow control, some of which can be passive EG flow control valves / needles and some of which could be active IE just switching off one zone, or proportionally switching off one zone (such as your actuators - which are Self balancing or should be) to allow the other to get the flow until some set point parameter is reached. The later 13:00-14:00 portions look like the 7deg delta that the Salus valves are trying to achieve. I wonder if a control valve for zone 1 has been fitted wrongly, or forgotten, somewhere allowing a return path that should not be there when only zone 2 is active? Can you post the install schematic?

There are standard metal fixings from Simpson Strong tie for this have a look here: https://www.strongtie.co.uk/products/detail/i-joist-hole-support/317 for I-joist there must be an equivalent for plain joists - found this one stateside: https://joistrepair.com/pages/applications

Could they not get straight battens / get the battens straight?

Is that the skeleton of a great crested newt I see in the bottom left of the picture? Good clean cut that.

Looks like wonderful project, time won't be something you will have lots of but finding enough for a blog is rewarding and perhaps useful - wish I had / was done /doing one.

Take a look at Kytun they have quite a range but I struggled to get them in black recently.

Probably 'oven ready' like so many other plans - targets are one thing delivering them seems not to be an issue - the target is the target - I will only be in power for a short time, I will speak great words and leave it to the next bunch to make the hard choices, after all nobody will vote to be taxed to the hilt so we can de-carbonise will they?

Evil genius types tend not to have tiny minds - the clue is in the word genius, but I appreciate the sentiment...

Do you think some evil genius is going around coating crossbow bolts with JKW spores and then loosing them off at the planters of people they find tiresome.

I have been getting the flashing together for the wall cladding and Kytun seem to have stopped, they sold me the last of their stock and were not expecting any more, making / supplying the dry verge below in black .. Any thoughts? Source: https://www.kytun.com/p/slate-dry-verge-alu-t1-18mm-blue_black/c01bb accessed 17.07.2021

You can probably bury them reliably with type 1 provided that they are somewhat spread out so the stone can get around them, if they are left piled up the voids will take a long time to fill and you will get holes appearing for a long time. If you cannot spread them out you need to do a good amount of crushing to prevent voids.

Hmmm sounds odd - did they explain their reasoning? Also 6cm / Meter = 1 / 17 while 1:60 is between the BR 1:40 and BR 1:80

+1

Are you looking to max out the SAP, (100+) or manage the SAP alongside other things? By which I mean, for instance, if you want any cooling from the ASHP then specifying one that is reversible can damage your SAP but will allow cooling, most are reversible after purchase, so no cooling for max SAP but after you move in you may feel you want it!

Welcome to THE forum for people like us - look forward to following the build and you will find plenty of help and support here - enjoy.

That does not look good. Your photos capture the problems. That is the wrong dry verge for those tiles it is for higher profile tiles than your flat ones - some might also argue that the colour is wrong but your choice. The gap at the bottom between the dry verge and the facia is not acceptable this should have an uplift to match the kickup of the lower tiles. The roof light fitting feels wrong as I thought that the tiles should go over the uplift, which is there to provide a channel and stop wind blown rain getting under the tiles which as things stand is an open channel. You can be sure of the fitting requirements by downloading the manufacturers detailing sheets. You also need to check that the flashing kit used matches the tiles - given the dry verge I wonder if it is correct - again you can check this with the manufacturers recommendations. The leadwork at the top looks very wrinkled and also looks like it has not be patinated evenly. I would ask the builder to get the dry very refitted and adjust the facia, show you, SHOW YOU THE DRAWINGS FROM THE MANUFACTURER, that the roof lights and flashing have been fitted in compliance with the manufacturers recommendations and get them to smooth out the lead and confirm patination.

Welcome to THE forum for people like us!