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Hello buildhub community, I've searched endlessly for my own answers but can't find it... Is my cylinder Stat on my solar system in the wrong place? Recently had a new solar thermal system installed with a indirect twin coil 300l unvented cylinder. Connections from bottom to top - Solar feed through the lower coil, then cold feed, then cylinder stat to boiler (about 1/3 way up, 2nd pocket up of 4), Immersion to iBoost, boiler feed through upper coil (about 2/3 way up, 3rd pocket empty). There are also 2 sensors (S2 in 1st pocket,S3 in 4th pocket) for the solar thermal system, but this is a separate system entirely. Obviously I want to ensure I'm not heating the whole tank unnecessary and what to make the most of the solar power. I plan, as recommended, to top up the temp in the top 1/3 of tank during evenings via a short, timer period from the boiler; relying on the the cylinder stat to stop heating when at 60C. I understand that the boiler will use the upper coil to provide 70C coming indirectly to heat the top 1/3 of cylinder by convention; But also understand the principal of stratification means it won't efficiently (or at all) heat the standing water below the upper coil. So how will the cylinder stat positioned only 1/3 way up ever know when the top 1/3 is the right temp? The installer said it will heat below the coil and there is a temp differential of about 20C between the cylinder stat position and the upper coil, so with experimentation if you set your cylinder stat to about 40-45C, this will be a proxy for 60C at the upper coils. Is this true? Or will the thermocline form and hold just below the upper coil keeping the heat where it is? The last thing I want is to fire KW of gas overheating the top 1/3 unnecessarily and the cylinder stat not used effectively. I'm testing the Installers theory each night when I top up. Should the cylinder stat be higher up the tank? I have a spare pocket which the instruction manual refers for the 'Dual control/overheat stat pocket (boiler)' which I think is really where the cylinder stat should be, in-line with the upper coils and best placed to control the Tmax. With all the knowledge in the world, its experience I lack... Any help improving my understanding and maximising efficiency would be welcome. Lee

Hi All, i recent brought a Vaillant AroTherm plus ASHP and have started to install it with a set of Vaillant AroTherm plus flex hoses that I purchased from City Plumbing. https://www.cityplumbing.co.uk/p/vaillant-arotherm-flexi-hose-750mm-20165288/p/130849?text=Vaillant AroTherm fl Previously it has been possible to shorten these flex hoses as the work the same way as solar thermal hoses. see here: However it Would appeal that they have changed the why they manufacturer the pipe. As there is no longer a circlip or bolt that fits over the corrugated pipe. Does anyone know where I can get a nut and circlip that I can use to shorten these flex hoses? The reason I need to shorten them is so I don’t end up with an air lock in the flex hose. hope someone can assist? cheers

I have an ASHP all installed and working. Also have a solar thermal panel - not installed, with a full drain back system. My issue I can't install direct to cylinder without quite a bit of work, but have very easy access to a roof space and ASHP flow and return pipes. So was thinking of coupling direct into either the flow or return of the ASHP via close coupled tees. Then put some logic behind it. Think return pipe would be better? So I need to do Take solar thermal when cylinder heating and heating UFH, but not when cooling. Typical flow temp for UFH is around 30, so should get a decent yield from ST even in winter. I could even switch off in the summer. What do you think, is it feasible?

Hello, I am in the process of replacing the LPG tank in my property with an ASHP (Mitsubishi Ecodan 14kW). I currently have 2 solar thermal panels which cover all hot water demand for 5-6 months in a year (and I'm planning to keep them). It has been really difficult for me to find a suitable DHW cylinder that (in my limited understanding) would work well with ASHPs and solar thermal panels. Even harder to find options where I'd be able to monitor water temperature at different heights. Ah - the cylinder volume should be 250 litres. I really like the idea of Mixergy tanks because of volumetric heating, the plate heat exchanger (more efficient), the diffusers (for better stratification) and all the data I can get from the tank. However, they are very expensive and, for the ASHP+solar thermal versions, I cannot do volumetric heating (I've been told so by Mixergy). More annoyingly, it seems there is no dedicated solar volume, so it'd be hard to make the most of the already installed solar thermal panels if I want hot water in the morning. The pre-plumbed Mitsubishi cylinder ticked a lot of boxes, but it has 3 pumps and my installer warned me of audible noise (the cylinder is to be installed in a bedroom cupboard). It's also very expensive. I looked at options from Gledhill, Joule, Kingspan, Heatrae Sadia, ... and neither of them looked perfect. Yes, I am likely overthinking here, but would anyone have any advice or experience they could share with me? I haven't ruled out any options yet. Thanks a lot!

Hi Ive recently moved into a house with a solar hot water system. It has a RESOL controller. Despite having the manual and generally being able to sort these things myself I cannot get the controller to adjust to the settings I’d like. is there a way of factory resetting them? anything I’m missing?! Thanks in advance.

Hi all, Been lurking a while soaking up the wisdom, while our plans percolate and mature. Already been an enducation! Just in the process ofr finalising the techincal specs for a new 5 bed house in Hampshire in the Meon Valley area. Some details of what we will be attmepting to lure others into conversation on same topics and steal their knowlesge...:-) Pile and beam foundation: After much to and fro between geotechnical engineer, architect and structural engineer on foundation type...I had wanted to do an unsulated/pasive slab which builder and I could have laid ourselves. Vetoed Hempcrete build as far as we can.Trying to build as sustainably as possible, interested what we can do with the material and helps to avoid competition for bricks...only competiing interests are horses for bedding...... Trying to get as energy efficient without committing to passive house as too constraining on design and I do like open windows at times. Still figuring out energy mix: Solar PV and thermal definitely, UFH, then debating on whether an ASHP or GSHP is going to pay back if the house is highly insulated. But how else do I cover the heating gap Recoup waste heat with MVHR. We are off-grid for gas otherwise I did like the look of the integrated Viessmann fuel cell/gas boiler. As in Southdown National park, stricty nitrogen requirements, so foul drainage going through septic tank and reed beds and pond to drainage field. Off mains drains. To manage rain water drainage on the plot I thought I might as well try my hand at creating a natural swimming pool. They are nice to look at and it will be an adventure! Anyway that is us for now! Hope to start the build in January for a couple of years. We live on the site in a bungalow which we have to demolish afterwards, so we can take our time and enjoy hte journey. Cheers Paul

Hi all, We are looking for some help with the best configuration of heating and hot water system. We will likely have oil on site, a wood burner and solar thermal panels. How would we put these together for the best system. We will have under floor heating. We could make room for a storage tank but we're thinking of just having an oil Combination boiler for the hot and heating until the Architect came up with solar thermal panels for SAP. We will only use the wood burner on occational cold evenings. Any guidance would be appreciated. Thanks, Geoff

Trade price list as reference point from company I purchased my ASHP and Pre-Plumb cylinder from. Secon Trade Pricelist Sept 2017.pdf