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1: Most ASHP's have a temperature probe that goes into a thermostat pocket on the tank. 2: Most ASHP'will have some form of call for heat / thermostat input. 3: Weather compensation will lower the temperature of water to the UFH when it is less cold outside to get the best COP from the ASHP. 4: I would personally have a 2 port valve for each manifold and one for the DHW tank. 5: you have a room thermostat for each zone, not each loop, a large room or zone will be multiple loops. All dealt with by the manifold control box. An alternative school of thought on a very well insulated house where the heat input is low, is don't have individual zones, have the whole floor as one zone. 6: I would always have at least 1 room stat per floor. The problem with all these general answers, is the details of exactly how each ASHP communicates and deals with the other heating components is not a standard thing and it varies a lot from one make of ASHP and the next. So expect the detailed design to be very ASHP dependant.

Not a breaker a fuse Dno fuse protects tails for the first 3 m anything else your own fuse is required.

Trying to bring the discussion back on topic, I checked the way I had reinserted the drain, and it’s possible I hadn’t replaced Everything exactly at it was; but at most we are talking about 1mm of difference. I pushed the drain piece down by that 1mm and have now been running the shower hose directly into the drain for 5 minutes, to see if I can recreate the leak. Nothing. Very odd. So either that 1mm difference in the position of the second item (the little 9cm tube) made a difference, or the leak is coming from elsewhere. I guess to see if it’s coming from elsewhere, I need to hose the edges of the shower area, and not just run the shower directly into the drain. But I’m too scared!

I went to one student let with 3 girls with hair down their backs ( no @pocster, just no ). I swear the offending hair 'ball' I pulled out was actually a dead otter. The girls only complained when they showered and the water got to the shower door and flowed over the top and then into the kitchen downstairs. I asked if they thought they should have stopped using it sooner and they just looked at me as if I was from a different planet! The kitchen ceiling had been soaked so many times it was actually drooping and breaking. This was a brand new refurbished HMO and they ruined it. Moral of the storey, choose your shower trap well, and your tenants even better

We tile lots of these Ive never sanded Worth sealing with SBR though

On the ventilation side under the sub floor, could you block the existing ventilation grate as it seems to be above the joists (perhaps that's the camera angle?) and install a number of telescopic vents across the external walls? https://www.screwfix.com/p/telescopic-underfloor-vent-black-220mm-x-215mm/12025?tc=GB2&ds_rl=1249404&gclid=CjwKCAjw1MajBhAcEiwAagW9MTRe19xMEgqXejvA3sjAJjfDdA4wfrH0MDBMF0D0CHKGi1uAmux9nxoCuXcQAvD_BwE&gclsrc=aw.ds

For future members who may be looking to purchase Intello Pro Clima membrane, Tescon Vana airtight tape etc, cheapest place I managed to find is a company in Germany. A search for Latzel Dammstoffe should find them. My order was with me within a couple of days, very keen pricing when compared to UK companies.

Only required if 2 differing RCD's are employed pre-CU? I've only ever installed an 80a switch-fuse at the meter when conveying tails of 3+m and above, and this is never a problem (no RCD required for the last few) but I'm not over the 18th edition like a rash tbh. If run in SWA there should be no requirement for RCD, but it may be requisite where the tails are sub 50mm from surface. You can screw into a live tail and make the fixing live, but with a SWA you'd have to short live to steel armour, so the tails need to be further away from 'attack' and the SWA less so.

depends, might need to be 100mA time delay to give sufficient discrimination

Yes would need 30mA RCD protection if under 50mm. so make the wall thicker at this point 😁or as Temp says run Swa surface to forgo the RCD protection.

I believe tails buried less than 50mm would need to be RCD protected in the meter cabinet. Many houses (mine included) have them run in the cavity but I don't think that's really allowed if you go by the book. Might be possible to use SWA tails not buried over 50mm but I'm not an electrician.

Or your brain will soon filter it out, if you let it. When it twigged that distant road noise was like distant waterfall sound, it stopped mattering so much. What does your air system sound like?

@IGP thank you - that's perfect. Let me know how you get on with yours! @Nickfromwales thanks... Mystery now solved. It wasn't really a mystery, a bit of digging and I found a cut off 15mm pipe underneath the gas meter. The pipe to boiler (now only gas appliance) is now in 22mm so all good there.

You need to do it. There’s almost certainly an issue somewhere and you need to find out where in time for the snagging.

what's that pink stuff around the copper pipe? if you don't know I'm sure @Nickfromwales will!

Don't forget to plan how to get cables through the roof, as that needs to be stitched into the fabric of the build before the roof membrane goes in / on. Cable snorkels are available which can be made airtight and are water-weather proof.

Do you have a sound attenuator on the supply side (extract as well)? this is what is needed to reduce the sound from the vents. I made my own for my first project and that worked very well. Basically an osb box with sound rockwool batts on the inside (with batts sticking out into the middle to disrupt the airflow - large enough to allow enough airflow). Second project I bought an attenuator (just cylinder with sound absorption ) and it hasn’t been as good as the one I made. I didn’t have a problem with noise from the machine itself - most of the noise was coming through the vents.

Roof goes down and gets proven as rain / weather tight. Then you install the plates and weld the skirts down atop the original covering.

Imaging two rooms in your house, both 3m by 4m, so 12m2. ONE is at the North East corner, with the 4m side running along the North wall. The other is on the diagonally opposite corner, with the 4m running down the West wall. The thermal losses, and gains, could be quite different.

I think it was Jeremy who mentioned just running the UFH pump to circulate the water in the floor(s) without the HP engaged. Great idea, and one I've adopted for my projects. I am using a dusk - dawn photocell to override the manifold pump(s) so they only come on when the sun is 'up', plus it runs for free then if PV is included.

Plus you can use the immersion on a night time tariff, maybe 3 times cheaper than day time electricity. Plus 1 for above good to give the heat pump a break with the cheap immersion

You get extra material from the roofing company, and send that off. They then manufacture the plates with the skirt made from what you supplied, so you have have no mix / match / colour & type indifference. We supply a design to the clients so the builder / client / roofer can install in-house. The rails go atop and you're done and MCS compliant without the extra weight. Without the ballast being down first and the height of that, you can then drop the array low so it's 'less ugly' to look at .

No idea yet, all will be revealed in the coming days! 😊

Have you already installed the roof membrane? 'We' favour Nicholson plates LINK and rails vs ballast. That install may be too exposed to use Van Der Valk rails + ballast LINK, unless its with pre-stressed concrete lintels and you've the kg/m2 allowances in place for the huge extra weight? It looks like you have a parapet all round? The perimeter rule is from MCS iirc, and mostly for in-roof systems and not so much so for on-roof. With on-roof you have a roof which is 100% weatherproof, and then you overlay the array atop, and this will allow for "infinite" arrays which can go ridge to gutter and gable to gable flush fitting. The caveat is that the fixings and rails ned to be specified to cope, but many systems have gone in with an infinite install and have MCS so yes, it can be done. The 200-300mm requisite is simply to allow for a slate / tile / and a half to be fitted to the edges and be finished accordingly, eg so the in-roof trays can be part of a robust weatherproof install. FYI, a few installers put the bottom of the panels too close to the gutter and the rain overshoots the gutter. One issue to watch / mitigate against.

Yes, boss. Just the words "me" and "sensible" don't seem to work in the editor here. Keeps auto-deleting.

Flow temp will be affected either way, as the cooler return will reduce the output of the ASHP, so that's just moving the 'problem' from one place to another imo. Truth is it's not actually a 'problem', and if it's within the heated envelope all latent losses go towards the target temp anyhoo. 6 and two 3's.

How do you reach that conclusion without knowing system volume and modulation capability of the HP? I agree it's incorrect to assume a buffer isn't needed, but surely it's equally incorrect to assume one is needed. I do agree 2 port if you need one and pref in return not flow to avoid any reduction in flow temp.

I always seal / prime with a proper janitors mop and bucket with a 25/75 mix of primer to water and lash this all over, saturating the surface and leaving it to soak up whatever it wants to. Mop it dry and then do the same again the following day 50/50. Then I prime as I lay using the 50/50 mix to wet the surface 1m2 at a time as the tiles go down. Never had a tile job go bad, so that's the method that I "stick" to. Same method for laying SLC, but I leave the puddled mix down and pour the SLC onto that for a cheeky change in viscosity. Flows like a dream then.

incorrect assumption.. 🫣 put a 2 port buffer in, ASHP stat on the buffer and then carry on as previous.

I would add to the design requirements - get the system sizing right. Not oversized (like many) and obviously not undersized. If you don't efficiency or comfort will suffer. Don't be tempted to 'go big' for safety, you will regret it. I presume that you have a good heat model and a good handle on ventilation rates?

2. Generally with ufh and multiple stats there is a "wiring centre" at each manifold. This has inputs for each stat and outputs to control the valves on the manifold. It also provides a BE (Boiler Enable) which is the logic OR of all the stats. Eg if stat A or stat B or stat C... calls for heat then BE is active. The BE signal can be used to control an ASHP or if there is a Thermal Store it controls the output of the Store. On systems with just one or two stats you don't really need a wiring centre but something else (wire and possibly a relay) performs a similar function. The BE signal also controls the loop pump on the manifold and any two port valves between heat source and manifold. Sometimes the wiring centre provides separate outputs for these.

It does seem odd to me, but then I am odd, that people obsess over something that we spend around 1/50th of our time doing. If a DHW system has limitation, learn to live with them, 7 million people with E7 manage it.

@Selfbuildsarah Also, contact Trevor at Cylinders2go and mention my username and the forum for a discount on the cylinder. Telford stainless has a lifetime warranty too, and plenty on here have used them.

I called at the plywood merchant today for a pack of structural ply and was told if I hang on till next week ALL there prices are coming down Makes a change So anyone buying Hang on a week or so I picked up 15 sheets of 25 mil OSB while I was there £12 per sheet plus vat Massive place but stocked to the rafters

Being tidy improves productivity. In my experience, it tends to be one or two people that make all the mess and slow everyone down.

Assuming that was meant to say storm drains(?) then maybe an opportunity to introduce that through the centre inlet and for it to be periodically washed through by rainwater. If it's a combined sewer that is?

I've not spoken with them, but on Debesto.com website they say they will arrange everything including delivery to the UK. A few people have told me that they have imported from Poland (post Brexit) and they've been very happy with the process, quality and cost. But no one will actually elaborate on who and how🙄😂😂 plenty of nay sayers whittering on about fensa and vat of course😏 I'm maybe 6 months away from the point of requiring windows so I may organise a little roadtrip/holiday via Poland to see for myself. Debesto.com (and a few others) are not manufacturers. They're suppliers/brokers.

I'm also about to go for the Ecological Building Systems approach to doing my suspended timber floors, https://www.ecologicalbuildingsystems.com/post/best-practice-approach-insulating-suspended-timber-floors and have just bought all the materials from Latzel in Germany (very efficient and prompt!).

Hi. In 30+ years of heating and hot water I have never seen a supply pipe in 15mm copper. I suggest you investigate this properly by lifting floorboards and identifying what gas pipework is in use, and what is redundant. The redundant stuff needs to be cut out and capped off by a GSR'd installer. Can you upload a pic of the meter, showing the connections and where they go into the floor / wall / other, please?

Global lumber prices have been falling so makes sense. Now almost back to where they were in 2019

I’ve had the MKM man visit my site 3 times this week flogging me kitchens, bathrooms, and doors. He also mentioned prices for materials coming down.

The only thing that may cause a real problem is if you cannot get your batteries close to your inverter. The reason for this is that the DC cables have to be large, AC ones don't. The general rule with ''renewable energy' installations is to keep all cable voltage drop to below 1% (I think this comes from a metering issue where placement of the meter can show different generation amounts). When it comes to pipework, just insulate it more than you think you need to. This can be as simple as boxing in pipes and filling with mineral wool.

If they do that, you have dodged a bullet, they would not have been a company I would want to do business with.

I'm sure for best efficiency installers like the two to be close, however, as long as pipework is properly insulated, and depending on distance the install may need a second pump to help push the water along...

They don’t need to be that specific. They just need to highlight the risks. They talk about the different approaches to building with some of the pros and cons of each so could easily cover it generically. They also have financial advice available so it’s something that may be covered there of course. Self-building is a risky venture even if you don’t have a company going bust on you.

Or plant rooms....

I used Excel and our resident window guru thought it was ok.

Not windows, but we just got frameless glass ballustrading from Lithuania. Half the price, exceeds the BC requirements and the quality seems fantastic. I'd definitely consider importing widows. At least then I'd know they had been measured correctly and will fit without needing handfuls of packers and cans of foam 🤣

What about those aluminium cafe jobs? And keep some cushions in a handy box by the door? I had envisioned this as my solution Like this:

My feelings are that almost any kitchen with fitted cupboards will tend to look better with under cabinet lighting for the counter tops - irrespective of the amount of natural light coming into the room. Once this is provided, the actual amount of natural ight is much less critical. Last April, when the cost of electricity tripled, I implemented an automatic dimmer to save power when the kitchen area was unoccupied. Being reduced to a lower level but remaining on means it still looks warm and inviting when viewed from adjacent areas. I note your letterbox window above the sink so maybe that area is covered but I don't know what's on the rear inside wall - that area looks to be the darkest.