Russdl

Yes, please do. It’s very interesting but complete Swahili to me. I would like to learn a new trick if you can spare the time (and start with the basics!)

I’ve got one in the garden on my weather station but annoyingly it quit recording the Solar Radiation a while ago. Consequently I’ve substituted Solar Radiation with PV Production so I can continue to bore my wife witless with my statistics. 😃

@JohnMo do you think you have a have problem then? We have had wall to wall sunshine down here for the last few days with hardly a cloud in sight so not at all atypical.

Significant difference down south. 27th Feb - 4th Mar 2024 26th Feb - 4th Mar 2025 The most noticeable result of the increased solar is the decreased heating requirement (the house is around 21 degrees). The heating last turned off at 05:30 on the morning of the 27th Feb and it hasn’t been back on since. It doesn’t look like we’ll need any this week and maybe not next week either despite negative overnight temperatures, down to around -4 to -5 on recent nights. Epic.

That’s a good point. We have zinc, formed on site and 600mm centres. 400mm would have looked better. Pigeon shite eventually doesn’t wash off completely either, so if you can get anti roosting wires/spikes fitted economically consider those as well.

@Onoff that is a genius suggestion. I’m now trying to find something around here that I need a Quinetic door switch for. @Pocster have you had a look at the videos on the product page in the link.

Thanks for that explanation @John Carroll much appreciated. 👍🏻

That's interesting, I've never seen temperatures even close to that after 6 hours of running. I've turned the pumps down as well to slow down the rate of flow, perhaps I need to turn them down further? I do have a 7°C temperature drop between flow and return which I believe is optimum. Out of interest, what size is your UFH system? Mine is 824 meters of pipe (no idea how many litres that equates too). @John Carroll Thanks for those figures. What is the maths, I can't work it out? That and @ProDaves comment certainly indicate that there is no benefit from isolating one of the Willis heaters, but the lived experience is different for whatever reason.

Wow, there's a lot of words up there. ⬆️ And some shouting. Just for the record I have no criticism of the physical installation in any way, it's a work of art. ~~~ I'm not sure how many people on here use Willis heaters for their UFH? I don't think there are that many of us? We only need one 3kW Willis heater to heat the house. We have two 3kW heaters plumbed in parallel. As someone who has lived with Willis heater UFH for a few years our experience is that having the water flow through 2 Willis heaters (one 'on' one 'off') mixes down the temperature of the water exiting the 'on' Willis heater. It would, wouldn't it. The water flows through the Willis heater at a certain rate (not exactly sure how many litres/min) but definitely not slow enough to get to any significant temperature before it's on its way around the system again. The highest exit temperature I've seen with a thermal camera is 34.2°C and that's after the UFH has been running for the best part of 6 hours (I set the thermal cut out to 40°C). At the beginning of those 6 hours it would have been around 22-23°C. The house copes very well with the one Willis heater providing the heat and, despite this January being unusually cold for us soft southern bastards, we've had a useful amount of sun to offset that and just running the one Willis heater has been fine. Anyway, as the prophet said "He's grown man so let him just carry on about his business please" and, as a grown man - I think I will 😃

Thanks for that, I don't think that document is relevant for the Willis heater arrangement but I appreciate the 'heads up'.

We have two Willis heaters plumbed parallel for our UFH. Generally only 1 is required to maintain the desired temperature in the 'off peak' window when the UFH is on. The idea was that if one failed we could turn the other one on for a seamless transition and keep the heat flowing. There was no way to isolate the Willis heater that was 'off' so I essentially had a mixer where half of the UFH return water would go through the 'on' Willis heater and be heated, the other half would go through the 'off' Willis heater and not be heated. When the two flows rejoined for another trip around the UFH coils the overall temperature would be reduced after this mixing. To counter this I fitted a couple of isolation valves so I could isolate the 'off' Willis heater and send all the return water through the 'on' Willis heater. The obvious problem with that solution is the risk of turning 'on' an isolated Willis heater (hopefully the built in over temperature protection would save the day!) My plan now is to plumb the Willis heaters in series. This would: Remove the mixing effect. Remove the need to isolate the 'off' Willis heater. Still allow system redundancy. Still allow 2 Willis heaters to be run at once if it got particularly cold and the sun buggered off for a protracted period. What are the flaws in that plan? @Onoff could you elaborate?

I'll start a new thread...

(thread drift) Would your new best mate travel to Salisbury? It's difficult finding a decent plumber. Come the warmer weather I want to re plumb my two Willis heaters from a parallel to a series layout, I was going to have a bash myself but if there's a good plumber nearby then that would be preferable.

An interesting theory regarding the transit damage leading to the PCM failure Jeremy and gives me a glimmer of hope that mine may survive as it was in good order when it arrived - as far as I could see… That slow heat up is interesting as well.

@SteamyTea that’s something I’d considered. We know some people have had issues with their Sunamps bulging (ours is perhaps a little plumper around the middle than when it was delivered, but not obviously so). Does the PCM expand and contract or just expand. If it is expansion and contraction then that may well cause a crack in the PCM containment vessel.

@Jeremy Harris that’s excellent news, let’s hope the current model has some subtle modifications to prevent a repeat failure! We’ve got a few years left on our warranty and I’ll be paying closer attention to our Sunamp in the future. It’s kind of easy to forget it’s there as it quietly goes about doing its thing (or quietly spilling its guts). Out of interest are they going to fix the damage caused to the house or have they swerved that one?

Excellent news Jeremy and well done Sunamp if you’re reading this 👍🏻

As you had so much input to Sunamp in the early days I’d be gobsmacked if they didn’t honour the 10 year warranty, even if the paperwork isn’t quite in line. 🤞🏻

@Jeremy Harris It should have a 10 year warranty on the PCM. Sunamp Warranty (pre June 2024)

Good to see you back @Jeremy Harris even if your Sunamp tale has me nervously looking into the utility room to check our Sunamp hasn’t gone pop! Im just up the road from you and more than happy to lend muscle to help you get the beast up the stairs, it’s the least I can do, your post etc were HUGELY helpful and informative for our build. Hasn’t your PCM core got a 10 year warranty? I’m pretty sure mine has.

Same as the above, our new plaster was pretty shiny, didn’t do anything to it apart from mist it 50/50 with some Wickes paint (specifically New Plaster Paint iirc?) No issues 4 years on.

Well done for fixing it but That can’t happen can it? Seems utterly bizarre.

It was a local metal fabricator but I’m pretty sure he didn’t fabricate them himself. He knew someone that did and supplied them to me.

We have porcelain tiles on pedestals. The ground underneath is anything but level and the pedestals we’ve used are from 50mm to 300mm high to give us a level patio. No grout required, water pours through the gaps. Jet wash it once a year and it still looks as good as new. As with @Andehh our tiles are the same inside to out. Slippery little bastards with frost on them.

I’ve just built a garage, slightly larger than your proposal but also within a meter of the boundary so had to be fireproof. Ours is single skin blockwork (clad in Rockwool EWI) and I used ‘C’ Section steel purlins for the flat roof and then plasterboard underneath. BCO were happy with that.