marshian

Meter reading at start 544.019 m3 Meter reading at end 544.439 m3 Condensate collected 612 grms Boiler run time 67mins Flow temp 30.5 to 33.6 Return temp 24 to 26.5 Avg kWh 4.66 kWh

Slightly OT but has that shower area been tiled onto plasterboard?? Ignore me it definitely has - not sure I'd be happy with that especially as you can see channels in the adhesive

From this thread OK then I've done this I was going to leave it overnight but in 60 mins of boiler running it's collected ~600 mls of condensate and I'm not 100% sure I'd be happy leaving it 8 hrs overnight

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I agree and a 10 year warranty!!!

Mine is a single tank BWT Yes it regens at 2am in the morning but not every night it has some sort of monitoring system so it only regens if the water usage reaches a point where it would have to force a regen in the next day so it does it the night before well that’s how it appears to work I stopped monitoring it a long time ago

if it does I can’t tell because the whole house bar one tap is fed from a tank in the loft - when a bath has been drawn it doesn’t seem like a long time for the CWT to catch up

Yep but older model it’s been in about 10 years

Took about 60 mins to install with the mains isolator shut - hardest bit was drilling through the wall to put the overflow pipe outside and getting an airlock out of the cold feed to the loft tank It's powered by a small transformer like a house phone charger - I assume it doesn't need a lot of power to run a control panel and work a rotary valve or two in the regen process Iooking back at my water usage it's probably accounted for a 8-10L per day uptick in usage - pretty sure that will be driven by the re-gen process waste

We have an un-softened water tap in the kitchen for cooking and drinking (yes this means that a year is good going for a kettle) We don't drink the water from any other tap as all the other cold and hot taps have always been fed from a gravity supplied CW tank in the loft

4 Bed - 2 occupants but we sized the unit for full occupancy (ie family of 4) We have very hard water. (from memory the test result was 400 but it might have been 600) BWT metered water softener - so regens by volume thro it rather than a fixed time interval It is powered 24/7 We use roughly 100 - 125 kgs of salt per year (tablets rather than blocks) so max £100 per year Before installation 1. A washing machine was doing well if it lasted 5 years 2. Shower screens, sinks, toilets and taps would need regular applications of limescale remover 3. When you washed your hair it felt like straw (According to Mrs Alien) 4. For clothes to smell of washing powder (apparently this is a good thing) it would take the max dose recommended After installation 1. Current WMC is now 10 years old (replaced just after fitting Water Softener) 2. Can't remember the last time we used viakal anywhere (If I could stop Mrs Alien using bleach (wrecking chrome and rubber seals) I would have a perfect life 3. Hair apparently in no longer like straw (According to Mrs Alien) 4. We have a line on the washing powder cup and it's sod all but the clothes still smell of washing powder (apparently a good thing)

That looks excellent - thanks for sharing an updated picture

No offence intended here - why is the best way to insulate a suspended floor by insulation under the floor ruled out I'd much rather do that when there is a std floor than have to do it later and ruin a herringbone floor Having insulated almost all the entire of my ground floor from underneath in a 2 ft crawl space due to a range of finished flooring above (Kitchen and Utility room tiled, Front Hall, hallway, downstairs loo and dining room 25mm Oak floor.) I'd choose ripping up a std wood floor and insulating from above in a heartbeat!!!

Wow that all looks quite snug Clearances around some of the pipes where they cross over looks tight for decent thick wall pipe insulation Has the room got any other heat source in it - clearly someone does the ironing in there

One simple sentence that explains so much

The radiator with the highest mean temp would be the one that emitted the most heat (that might not be the highest difference)

He didn't say his floors squeaked He asked the question "would option 1 lead to squeaky floors?"

Just to show potentially how much a leaky cistern could hurt here's my water usage when I had a a cistern that was overfilling and letting water flow into the bowl due to a failing fill valve It was in a the downstairs toilet which is rarely used and was the only explanation for the increase in water usage The £ killer is not the billing for the water used it's the £ sewerage charge based on ~80% of the water used

@Nick Laslett have you got any pictures with the in roof install finished? I will at some stage need to strip my south facing roof to replace the felt (Old bitumen style felt from the 80's) I have a small stock of spare roof tiles from when I did the extension (I could still get the original tiles then) but the in roof solar PV looks like I could get away without trying to find seconds to match the existing tiles.

comes with wifi connectivity out of the box so all the parameters (boiler run time, cycles (starts) all avaliable - if the house heat loss is 8kWh at -2 I’d go for one of the OP’s selections because at 10 deg C OAT they would be a good match but if the OP’s heat loss at -2 was 4kWh I’d go for the viessmann - low and slow like a heat pump is a much better way to heat a house

Sheesh....................... I posted it because it's useful to have an expectation of what your return temps are likely to be based on a lowered flow temp. 30 Deg Boiler Flow Temp 20 Deg Room Temp You aren't going to get a DT of 20 and a boiler return temp of 10 Deg I think you need to consider the audience that the blogs are aimed at - mainly the general public / DIY enthusiasts It's a "rule of thumb" - a "guide" call it whatever you like it's not "Gravity" They do training sessions for Heat Engineers that are way more detailed

Unfortunately the three boilers shown compromise space heating min output by increasingly high min modulation I'd pick the smallest one on that basis Actually I wouldn't I'd go for a Viessmann 200-W and have a CH min modulation of 1.9 kWh regardless of how big the HW side was https://viessmanndirect.co.uk/Catalogue/Residential-Boilers/Viessmann-Combi-Boilers/Vitodens-200-W-Combi-Boilers/Vitodens-200-W-35kW-Combi-Boiler-Z020316 HW 17l/Min @ 60 Deg C for the 35kWh Combi CH Modulation range 1:17

Fix the leaking cistern - if the noise stops happy days that water leak could cost you a significant amount…….

Table generated by "Rule of thumb" Heat Geek article said As the controller causes the return temperature to drop and get ever closer to the room temperature, it becomes increasingly more difficult to shed the heat. This is because the 'heat transfer coefficient' of the radiators drops. For example, if you have a room of 20°c you'll never be able to get a DT of 20 if your flow temperature is for example 30°c. A more realistic target is a DT that's around 30% of the flow temperature. For example; If we have a flow temperature of 70°c, (70 x 0.3) gives a DT of 21°c. If your flow temperature is 50°c this would give a DT of 15°c (50 X 0.3) and so on. This is not exact, it's just to get the flow rate in the right ballpark. There are more complex calculations for this if you need but really not worth it.

To get your head around all aspects of boiler sizing, efficiency optimisation etc etc have a watch of this