MikeSharp01

Your pic shows a rather poor connection between the pipes and the floor above, at least in the bits we can see - air is a reasonable insulator so as things stand you are not getting the heat from the pipe into the floor very well, can you still access it or are you beyond that stage already? Going forward there are perhaps two approaches. Try to stop all flow in the downstairs and then experiment with the upstairs manifold flow rates and the water temperature (+delta T) to see if the upstairs system can be adjusted to cope without the downstairs in circuit. (Keep notes of the present settings so you can return to them at any point.) If it can't then you may need to fall back on making the downstairs do all the work. Do the heat calcs - how much heat you need out of each zone for the length & diameter of pipe, coupling losses, area of the zone etc. Then adjust the flow rate settings in the controller for each zone and see what happens. I get the sense from your original post that the bathroom is your principle concern so maybe just run / play with that loop. Get a gun type thermometer to measure the temperatures everywhere (pipes, floors etc).

Finding pressure drops for components in heating systems can be a pain and while I was looking to do a more detailed analysis of our system prior to install I came across this paper from 2019 that gets well into the weeds of the pex-al-pex pipe and fittings. Well worth a look if you want to understand the details and see the difference a coupler, a union and direct connection. Link is: https://www.e3s-conferences.org/articles/e3sconf/pdf/2019/26/e3sconf_eko-dok2019_00045.pdf

I suspect we need a bit form information / knowledge to help reliably: Is it all coming from 1 manifold or more than 1 (how many)? Do you have multiple pumps in the system or just one? What is controlling the flows is it individual loop actuators or some other?

You will find exporting excess PV difficult if it is not an MCS certified install.

@JamesP & @nod thanks both.

I am just putting the ceilings up where we are using resilient bars and wondered what the best approach would be A or B below. The joints will be tapped but in A are you likely to get movement between the boards? In B you have only a very narrow space to place the screws.

Post a picture or two so we can get an idea what they might be.

Yes I think there is, I am 'in negotiation' now. 22% is a good compromise perhaps and -10 is plenty down here. I think I need to look at the delta T because that has a big effect on the head loss, I just need to keep the interface (between the screed and the wooden floor) temperature below 25 degrees C to meet the guarantee on the floor so its not going to be big if I want 21 deg C room temperature is it.

Many architects and independents offer this service. I chose to take the course, buy the software (excel spreadsheet really) and do it myself, seems to have worked out OK for us.

Coolenergy CE iH6+ and Thermox DTX. My problem is our longest loop at 185m of pipe over 40m2 of floor. I put it in when I expected a solid polished floor and thought the 1.5m head loss would not be a problem but now we are going for a wood floor with a TOG of 1.5 so the picture is very different.

Interesting link! Just got told by our ASHP supplier that Glycol is a requirement of their guarantee! I re-did my flow / heat output calculations and found that 30% of their chosen Glycol will push my pump head requirement up by approx 100% I am now looking seriously at antifreeze valves! We sort of had this discussion back in 2022/23 (and occasionally since.. Not sure we reached any conclusions but the additional pump head requirement does not seem to have been featured very highly in the discussion while the difference in heat transfer does.

Yes of course sorry. Can't edit it now. That's all done.

That feels too big, do you mean l/hr?

Yes, that's why I use two and if they don't agree I dig deeper. On our system, which I will post for a sense check in a few days, I did it by hand then with 3 LLMs which didn't agree with me so I got them to explain why we differed and then reworked it until we all, well 2 LLMs and I, got to the same point. Which was better than going for my first calc because, it turns out, I had the wrong chart for pressure drop on the pex-al-pex and the TOG rating of the wooden floor wrong. Chat GPT worked best in my view.

I did the calcs with 28mm because ours is 28mm so was interested to know the figures and given the size and relative difference I figured it will scale OK.

Its not wasting our time, many of us want to understand this better, and its adding to the community of knowledge that pretty soon everybody using the LLMs will have access to as well. I Just asked Chat GPT and Copilot to run the calcs on this query: "I have a flow rate of 1000l/Hr in my heating system and 28mm copper pipe work (external Diameter) I need to realign the pipe work using either 2 90degree bends or a single flexible pipe. Can you give me an analysis of both options in terms of pressure drop please." From Co-Pilot I got: Comparison Summary 🧩 Design Implications The flexible bend offers ~80% lower pressure drop, which is beneficial for pump efficiency and flow stability. It also reduces turbulence, which can help with noise and long-term wear. If space and installation constraints allow, the flexible pipe is clearly the hydraulically superior option. From Chat GPT I got: Calculated pressure losses — summary All values shown in Pascals (Pa); 1 Pa = 0.01 mbar. Two 90° long-radius elbows + 0.5 m copper elbow minor losses: 2K(ρv2/2)=2×0.3×(ρv2/2)2K(\rho v^2/2)=2×0.3×(ρv^2/2)2K(ρv2/2)=2×0.3×(ρv2/2) ≈ 80.7 Pa friction (0.5 m): ≈ 61.3 Pa Total ≈ 142.0 Pa (≈ 1.42 mbar) Two 90° short-radius elbows + 0.5 m copper elbow losses ≈ 242.2 Pa friction (0.5 m) ≈ 61.3 Pa Total ≈ 303.5 Pa (≈ 3.04 mbar) Two very sharp 90° bends + 0.5 m copper elbow losses ≈ 403.6 Pa friction (0.5 m) ≈ 61.3 Pa Total ≈ 464.9 Pa (≈ 4.65 mbar) Single flexible connector, 0.5 m long (same ID = 26 mm) friction (0.5 m) ≈ 63.2 Pa (plus small end fittings—typically tens of Pa if any) Total ≈ 63.2 Pa (≈ 0.63 mbar) Recommendations If your flex connector has the same internal bore as the copper and is reasonably short (≈0.5 m), go flexible for slightly lower hydraulic loss and easier alignment. If the flex has smaller ID or will be long, use long-radius elbows or re-route with larger-bore flex — avoid small-bore flex for flow-critical runs. If you want exact numbers for your exact components, tell me: actual pipe wall thickness or measured ID of your 28 mm tube, the internal diameter and length of the flex you’re considering, and whether your elbows are long-radius or short/standard. So my thoughts are: They are both within a few pascals. They do make assumptions and of course they know nothing about how tortious the flexi will be bent but it looks like, assuming they have both not hallucinated, the flexi option comes with a lower loss BUT if you look at the difference in head loss its only around 25mm (0.025m) between them so not that significant in your situation.

In theory yes, but might a couple of large diameter flexis not make all the transitions smoothly and so remove the need for the 90 deg angles everywhere.

Two things we, my other half and I, learned from doing it really. First thing is to get the membrane which must be the reinforced type with the embedded net, as tight as you can so you limit the sagging you get when you pump in the cellulose. Secondly use the widest sheet of membrane you can get. We used the 4m wide stuff from intellio. Many fewer tape joints. Our fixing was to clamp the membrane between the rafter and a counter batten running along the rafter with screws going through pre- drilled holes in the counter batten. Screwing ensures you can get it really tightly clamped and the holes make sure you get no jacking so you get an air tight seal around the screw hole, which if you think about it is actually filled by the screw anyway. Once the cellulose was in and we had done the seals round roof lights and windows we got a 0.2 score on the passive house air test so something must be about right.

+1 to most of that: We had power floated the garden room and it worked well we have an acceptable surface in there BUT the main house was not because: 1. It was very hot over 30OC 2. Much bigger roughly 3 times the area of the garden room. 3. Not enough people, we had 5 working all the time, but only two of us had the experience on the garden room. 4. We didn't have a long enough floating bar - our hire people let us down on that, the long bar was not available, so we needed more passes which took more time than we had given the drying rate. In the end about 70% of it was more than acceptable but 100% is the only answer unless you want level changes in your floor areas. It was a disappointing day but we knew the risks and accounted for failure in the plans - eg levels. As an idea of the cost of failure the flooring cost for us is about £18K more than it would have been had we succeeded which might put the £32K somewhat into perspective for you. All in all my advice is not to try it yourself, look at the balance of costs and get a few more quotes.

Welcome to THE forum for people like us.

You do need to measure the floor temperatures, get a cheap IR gun. (the one below is about £50 from Screwfix but you can get a lot cheaper, 1/3rd the price, versions from amazon). Have you replaced the floor coverings since the Oil boiler? If you have then the flow rate thing will need to be tackled see posts above but also you need to watch out that you do not overheat the floor. You can also work out the TOG value of the laminate, which will give you an idea, along with a bit more working out, just how much to increase the flow rate and / or the delta temperatures across the system.

Keep on keeping on and all will be well, all the best.

Which model is that? We are looking to install the Cool Energy CE-iH6+ which delivers 1.85-6kW @ 7 degrees and at -3 degrees 1.2-3.9kW which is about bang on for us where we need 1.139kW according to their calcs.

I think of PFC as Power Factor Correction assuming this the possible reasons are all over the place but as @Michael_S says could be a mains glitch that took it out of range. If so it probably will not recurr but if it does you will need to dig deeper loose wire or something that causes the motor a problem which I suppose a high speed gust of wind right up its axis might well do.

Interesting! You need to pack it round underneath with as much PU as you can, get some wood along the top of the beam + down the side of the flange at the top and foam fill all the voids down the sides. The fixing of the ridge tiles can still be done with cement as you would be fixing to wood.