MikeSharp01

What other 'services' are going into the trench? Will they be ducted? You may need to layer the other services to achieve any separations that may be needed. Heaping the top soil is a good idea you can use pea shingle in place of sand then I would put a layer of type 1 and compact it then the rubble rock then compacted type 1 again followed by top soil and final compact.

Glad it all worked out OK.

Once you have been over your design with a fine tooth comb your electrician can do the cabling at first fix and then return to it for second fix and anything they missed will be their need to fix, which at that point can be quite expensive - or you use radio switches to get around the problems which as @nod says are/is rare. You need to think about how the multiway switching will work with dimmers and if its complex you might like to consider radial wiring where for the lighting where everything comes back to a central point and the interconnections are made there that way, provided you have installed enough 'ways' to the boxes you can wire it how you like back at the box. Also radial allows you to have complex controls in the middle and simple switches at the boxes.

TBA I don't know, my friend who has a licence takes my stuff down there for me and he gives me a receipt - I do know they no longer deal in cash so I would be ready for both an account and some ID.

Yes we have one in Kent - odd isn't it!

Welcome to THE forum for people like us. Probably need some pictures to fully understand what you are saying but are you saying that the retaining walls have soil on your side and nothing on the other side?

+1 it works, don't worry about it.

In addition to one under the slab, in the ground to all intents, and a couple in the middle of the zones I placed one sensor, pocket pipes anyway, In the floor about 1m back from the windows. It struck me that I might like to know if the sun is doing its job before it gets ahead of us and to allow me to move heat from zones getting sun to zones not getting sun. I swither about this being a good idea or not, when I put them in I am sure I had a way of determining a control schema but I cannot for the life of me find my notes and right now, in response to this thread, I am struggling to work out what the plan was.

Good to hear, it was a long shot anyway.

Just while I remember, daft thought but worth eliminating - there is no chance that the low loss header has been put in upside down?

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?