First off, I'm me, no-one else. I can think of better things to do with my life than create various alter-egos then pretend to talk to each other on the computer. Don’t think I even had an imaginary friend when I was little.
Right.. as listed
1. The CH zones can have TRVs all around using Smart pump. A great advantage.
...We already have trvs on most rads, but a few older ones without, pump is an Alpha with a bypass fitted as well – not sure we needed that, as it was bleeding hot water back into the store return, so I’ve wound it up a bit now, forcing the pump to back off when trvs are shutting instead – to start with, I reckon we were getting 60-70 deg water going back in at the bottom. Now I know more and more to the point understand it, I’d use a 3-way mixing valve with a sensor that keeps store return temp low – if too hot, it gets sent round the rads again. Planning a laddomat 21 on the stove boiler – this does same thing returning the correct temp (this time not too cold tho’) back to the heat source. If stratification is essential, a clever valve probably is too.
2. Stratification is important to keep the return temperature low and the DHW temp high. A tall cylinder does help a lot.
...The stratification thing is a Big Question from reading around all this on this forum and elsewhere – ours isn’t so much, as the plate X is big enough to cope – had a good shower (admittedly in summer with warmer incoming townswater) with the top of the store at 55-60 only, and whatever we do, the boiler’s still showing a temp diff across flow and return of 20 deg or more right until the last couple of mins of a firing.
I think, from reading, that if you have a thermal store with an internal coil somewhere in the top third of the store, it’s more important to get the stratification correct – one blast of cooler water up around the coil, and the shower falters – our plateX taps into the store right at the top.
3. You can put a CH pump interlock in. When reheating the cylinder the CH is switched out to give a fast re-heat.
..Good idea but no point as far as I can tell – once the rads AND the boiler are on eg first thing in the morning when the roomstats and store call for heat, I suspect the energy goes straight into the store then back out again. Only once the rads are calming down does the boiler get a chance to charge the store.
One thing I did do, was try a pipe stat on the return from the rads, to cut the rad circ pump if return temp to the store got above a certain temp. Didn’t work! Just meant the pump stopping then clicking on for a few secs then off again to wait for the section of pipe to cool again. As said above, second time around I’d do a 3 way mixing valve to filter out warm return water.
4. You can switch out the CH pump when the DHW is called too. Then a few simultaneous hot showers will last and last.
...Tell you what – doesn’t make any difference – can’t get a cold shower in this house now unless it’s the third in a row.
5. How long does it take to get DHW from a cold re-heat - say a useful sink full. It should be a few minutes as it heats top down. An unvented cylinder heated by a coil would take a long time.
...To be honest, so far I don’t think we’ve had a problem with waiting for hot water - it'd have to be under 50/55 deg at the top to struggle - a coil WOULD struggle. And the shunt pump is still only on speed 1 out of 3.
6. How long does it take to reheat the cylinder and what kW is the boiler?
Is the boiler temp set to maximum?
...Boiler is an EcoMax 28kw (too big really, but it was dirt cheap as it’s an old model). If I did it again, I’d have a dinky 12kw thing running it’s nuts off instead. Boiler temp is set to max – 82 degC. The theory I’ve found elsewhere is 300 litres stores about 18kWh of energy at deltaT of 50degC, so my 20 to 30 mins running is about right if I’m putting in 28kW. I think! Not a mathimagician.
7. I would fit a Magnaclean on the CH return to the heat bank, not on the boiler return, if one is not fitted already.
...Check! (but on the return to the boiler from the store, as that’s where it fitted best) Thinking about it, it should be nearer the rads, then any crap from the old system doesn’t get into the store first. Fair point, we never thought of that.
quote]
If you’re daft enough to try something like this, if you want to burn wood, gas and use solar, without the internet or a german dictionary you’re on your own.
There’s here,
screwfix, navitron, green building forum and a couple of others. The yellow pages or high street is useless, from my experience.
Without internet, I’d have a combi or an unvented solar cylinder with system boiler, and a nice trendy standalone woodburning stove.
Who, of the pro’s on here can seriously say they’ve ever fitted something like this and made it work?
Maybe you’ve done two this week already, maybe it’s just me, but I couldn’t find anyone when I wanted someone to do it – in the end I got lucky and a relative of a friend (who fits solar, ufh with stores etc etc) did it, more for a weekend challenge than anything I suspect, but he understood the theory as he fits stores for ufh anyway, and was willing to give it a go and spend time on applying the theory to copper pipe and plumbing bits, which seems to be the biggest hurdle – giving it a go, not defaulting to the easiest option.
A boiler coming on for ten minutes every time an arbitrarily selected room’s temperature drops a degree is a waste of gas.
Running a tap for 20 seconds before the combi gets its act together is a waste of water.
Throttling back the shower when the weather gets cold as the hot water drops away, that’s easy.
There is good stuff out there, good combis, unvented cylinders, but without good controls, accumulators or big mains pipes, weather comp etc, none of it works as efficiently as it could, it's frustrating, and you're more often than not directed to the easy option.
Plumbers merchants for example – I have found just one man, in one merchants, who was willing to take the time to get his head around this.
Shaking heads everywhere else. Not standard. No idea. Move along now, there’s a queue of people waiting for pushfit plastic and £299 combis.
Someone has said above that I should get Gritish Bass in and video them. I would, but I don’t want them fainting and impaling themselves on a valvehead or summat.
If you think this is all just daft and I'm here to wind you up, go have a look in Europe – stores the size of garden sheds are used, 2500 litres or more, automated wood gasifying stoves that’ll only need running three times a week because the heatbank stores 2 days worth, multi-panel east-west solar, unvented wood burning stoves with all the control gear and safety systems to go with it, the list goes on, and I'm still learning about it - if I did this again, there'd be changes that's for sure, but what me and the heating engineer have done has succeeded, it bl**dy works, and works well, and I'm chuffed to bits with it.
Take weather compensation and it's use in the UK for example – standard practise for years abroad. We think we’re cutting edge with two roomstats.
We ARE doing some of the clever stuff here, eg Advance and others, mainly for ufh - but it’s generally thought of as mad scientist territory.
Whether it’s because we’re an island and insulated from the rest of Europe I don’t know, but we’re (generally speaking) still in the dark ages.
And discuss
And NO I'M NOT BIG BURNER.
