marshian

Back story here

I don't get a lot of turbulence with a vertical top mounted element and you certainly get a very defined stratification with minimal heat transfer to water - down side to my element is it's quite short, maybe less than 1/3 of total tank height so it really only heats about 50 litres max - just enough for two decent showers or a shallow bath

Oh I get that and 'it's why I might (in the interests of "science" ) move the bottom sensor up to a position on the outside of the tank level with the end of the immersion It's a top mounted vertical immersion in a 115L tank and it has it's own internal thermostat just as yours does Question will be at what point the internal thermostat signals re-heat and after how much water has been drawn off? gut feel from how we've used it before is you can pretty much use 70% of the water before it will kick in again and try and reheat so maybe 40 litres

OT I lived for years first on a Volvo 3.0 CD and then a Senator 3.0 CD plate was relevant to both 😉 rather than to me When I couldn't find another Senator that wasn't full of tin worm it carried on first on my BMW 740i and now on my current BMW "130i" I did get a daft offer once from someone who wanted it for their Audi A3 but I kinda like it and 30 years is a long time to have a plate

I don't think that would tell you anything meaningful unfortunately This is what I have on the tank (Library picture from a legionaires cycle to 61 deg C - followed by pouring a bath) the top one is looking at the top of the tank - the bottom one where the boiler tank thermostat is I'd need to put another temp probe in or move the bottom one up to roughly where the immersion element ends to get a better idea of hysterisis

Makes sense now I'd do exactly the same (I have OCD too - hence the plate on one of my cars)

Looks like I'm going to have a play with the original spreadsheet and @AartWessels web based app I originally did heat loss calcs with https://heat-engineer.com/en/ From memory £12 paid for a single one off survey - took a bit of time with a tape measure but the results for my submission were pretty accurate v real world energy usage over the winter and it felt like good value I've recently improved a few aspects of my house as well as moved to a low temp heating regime and I want to to do another heat loss survey to see what I could expect compared to the original Price now for a single user / single survey is now £100 not sure that represents good value any more

Well done - clearly the poorly installed installation was very much the driver for your heat loss issues - only thing I don't understand is why there is a mixture of materials - surely with the roof off it could have all been kooltherm PIR?

Brick acid will normally take off sealant - however it is very aggressive stuff - A friend of mine arrived on my driveway in a car leaking a lot of very hot transmission fluid - it went straight past the sealant on the brickweave and all the normal gunk/jizer oil removal preparations did nothing - brick acid worked but it's obvious which bricks were treated - the surface finish is very different

Do you live in an area that gets a lot of driving rain and or the house is in an exposed location?

couple of points 1. You could but the output might be horribly compromised - heat rises and doesn't sink so the top of the rad might be warm but there won't be a lot of heat traveling down. 2. Most "good" vertical rads clearly indicate inlet and outlet in order to work with the diverter that is installed in the rad (I'm not sure they can be fitted upside down either you need to discuss that with the manufacturer) 3. I've linked to my post about my experiences with a couple of oval vertical column rads as not all manufacturers have the same level of quality control and diverters are crucial on vertical rads in low temp systems 4. I'd run the pipes behind the rad and feed from the bottom (maybe paint them the same colour to hide them)

Similar arrangement for me but only time I use the immersion is when the HW/CH system is drained down for changes in the summer. My thermostat is set to 55 Deg C it's only a fairly short element maybe 40 L but that's enough HW at 55 deg for two showers or one shallow bath (I have a tank temp display and from memory the thermostat was quite accurate v the temp sensor) I can't help with re-heat set points as we heat only when (or just before) we need it so I've never noticed what hysteresis is applied

My question as far as you wanting to run at "low flow temps" are concerned is just how low will your oil boiler go down in terms of flow temp? I think this is an important point as you need to size the rads for the lowest realistic flow temp that also keeps the boiler happy I heat with gas and previously had a glow worm condensing boiler that was oversized for the house 24kW - I upgraded all my rads to match the heat loss at a flow temp of 40 deg C but realistically 48 deg C flow temp was as low as the boiler would run without excessive cycling and I ended up running it slightly higher and controlling room temps with TRV intervention (which isn't great for cycling). Moving to a new gas boiler (I wasn't brave enough to go ASHP at the time) it happily runs in from mid 20's to low 30's (Weather compensated flow temp) - only had to change one more rad to balance the house warm up (one room took way longer to get to temp) most TRV's are set to elevated target temps that can't be achieved in order to minimise circuit shrink due to TRV's shutting down. All Rads are fed with the flow they need for the WC flow temp although I am planning to improve this area as the Drayton EB4 TRV Bodies only have 6 flow settings and I could do with a slightly finer adjustment on a few rooms so I'll be changing a few for Danfoss RAS-B2 TRV bodies as they have a finer adjustment for flow rates House is heated 24/7 no set backs - it's way more comfortable at a lower room temps because there are no temp swings, In the heating season the boiler cycles once per hour max - the length of the cycle determined by the heat loss If the old room comfort target was 22 it's now 19 to 20 max House is 4 bed detached - extended with a 2 storey ext - is a stupid T shape with several rooms having 3 external walls - some insulation improvements - floor area total across two floors is 113 m2 and peak heating at -2.5 is 39W/m2

just for info I have a lot of data on gas usage for my house and one thing that really stands out is summer DHW usage is very very different to winter DHW usage. in summer tank losses are lower due to higher ambient temps in the house water from the mains can be 10 deg higher in temp coming into the house typically my summer DHW usage is 3 to 4 kWh for the heat up - Winter it's closer to 5 kWh - that's a significant % increase that you probably need to factor in MCS I agree is a bit crap - worst case on worst case - might be worth ignoring the grant element and pricing up what you need without EPC pretty much fiction and not really a good guide

Still here - watching because I want to see a happy ending…… prob page 1367 at this rate 😉

Separate pump for rads? Turn pump speed down and or open up lockshields and run rads same temp as UFH if sized correctly I hate system noise it’s a sure sign something is working harder than it should

Anaesthetic hasn’t worn off yet so currently no pain at all - pretty sure that will change soon

Might be a few days before I start back on it surgery I’ve been waiting 2 - 3 years for I reckon @JohnMo will have his finished before mine 🙂

I've used two of these in the past for an awkward soil pipe to pan angle - try to get one with ridges on the rings that lock up the joints as the smooth finish ones are much harder to get tight. (Flo Plast ones definately have that)

Then I think I'd be avoiding them and going for a supplier of known and guaranteed suitable material

If you have a heat loss (w) required by the room then it really is simple Lets take the example of the Room 1 - from the table you supplied heat requirement/loss is 612w So you need a radiator that supplies 612 w at your target flow temp Radiator outputs are normally stated at Delta 50 (Flow temp 75, Return Temp 65 so mean rad temp 70 Deg minus room temp 20 gives difference of 50 Deg. Rad outputs by size and type can be found here https://www.stelrad.ie/wp-content/uploads/2015/08/Compact-K3-Technical-Specification-Brochure.pdf Taking a T22 Rad (double panel / double convector) which is 600 mm tall and 1400 mm wide it has an output of 2.425 kW (2425 w) at Delta 50 Correction factors DT50 is 1 DT45 is 0.872 DT40 is 0.748 DT35 is 0.629 DT30 is 0.515 DT25 is 0.406 DT20 is 0.304 At Flow temp 45, Return Temp 35 so mean rad temp 40 minus room temp of 20 gives a difference of 20 Deg (or Delta 20) so the correction factor for that is multiply the original rad output by 0.304 2355 multiplied by 0.304 is 737 w so a little over what the heat loss required is so you could reduce the size a little but I'd go a little bigger everywhere and then tweak the flow temp back a smidge. The key for me when up-sizing rads is to try and ensure all are up-sized by similar factors for all the rooms - I made that mistake myself in not thinking about whole house heat up being balanced. With ASHP your rad flow temps and return temps are going to be a lot closer than the 45 / 35 but the important thing is the radiator mean temp so a rad is going to give the same output at 45/35 as it will at 42/38 or even 41/39 If you are looking at designer rads, vertical rads or towel rails up-size a little bit more because in my experience they are a little optimistic in terms of output and that impact gets worse as flow temps get lower Highest Flow temp (central heating) that I ran my gas boiler at through Dec, Jan and Feb was 34 deg C - house is all rads (no UFH)

And done……. well the big lift is done rest is down to me

Lift planned for tomorrow a little more clearance created today

they are an absolute cow to fit which is why the fitter didn’t use it - plenty of soap and a steady equal force - especially when doing two sides at same time

Don’t they say the expensive part is getting out of the ground - well done - I’m sure it will be plain sailing from now on