marshian

OK Allen Key in the centre - anticlockwise to open more clockwise to close would be my guess

You don't need to understand WC - It's really not hard Houses lose heat As the OAT drops the house heat loss increases You need to put in more heat to maintain the house temp WC just changes the flow temp with ref to the OAT to compensate for the losses based on OAT Get your curve right and there is no change to the internal temp regardless of the OAT Bingo house internal temps don't change because boiler / ASHP flow temps do

Did it get warm previously? If you haven't fiddled with it since last time it worked why do you think is suddenly become shut It's more likely your issues are with other rads stealing the heat before the flow gets to this rad - decorated any rooms recently?

Similar here (I won't repeat myself here) except I've not transitioned to ASHP yet. I've still got the "smart" TRV's but they are serving me well whilst I get the Danfoss RAS-B2 rad valves aligned to the room temps (the app gave me a starting point for all my T22's and single K33 but it's not great for vertical rads - once that's done conventional TRV heads are going on (Just as temp limiters for solar gain in the shoulder seasons) and WC can take care of the house temps 24/7

Yeah it's perfect for the two of us in a 4 bed detached - no need to worry about Legionaires when we pretty much deplete all the water every day Thank you - It's a bit busy in there but I've tried to keep it neat - the insulation is decent Tubolit Polyethylene Pipe Insulation (not skimpy DIY store stuff) with almost identical OD for 15mm or 22mm so I have a tube mitre block set up for 30, 45 and 90 deg cuts I pre-make 90 deg bends and glue them with off cuts (from the last time I did any insulation below the floor) and then I only have to fit bends and then measure the length between them and cut the lengths accordingly

No idea - certainly it seems like it's got a pretty wide hysteresis judging from the overshoot It's been in there since 2012 when the tank was replaced - previous tank was un-insulated copper tank with a puffer jacket that developed leaks after fitting a water softner. Tank replacement is on the list of things to do when I can justify the expense.

Single element electric immersion - Gas boiler Off because system drained down Hmmm it's not very long - 3KW draw - Tank capacity is about 114 Litres (guess based on our daily water usage - up to 4 showers at 30 L each one blended from 50 deg C HW temp to comfortable shower temp) I can heat enough water with it for Mrs BC's bath night but I need to set it to 60 deg temp to ensure she doesn't run out of water mid pour Won't be till next Spring when I do the adjustments to the heating circuit under my suspended ground floor - was on the list for this year but I've missed my window I think that would be the case for a side mounted immersion depending on where the temp is picked up from We only have the immersion for "emergencies" (boiler failure or replacement and when the system is drained) it's always been on a three pin plug (for 34 years!!!! - it's on the list to put it on a wall switch but I only ever thing about doing it when it gets used which isn't often - this is the second time in 12 mths)

Is that considering the utterly dreadful efficiency of 50-60% of a CCGT - I get your point about transmission issues (and losses) for gas supply but I'm running a gas boiler at 97.5% efficiency on CH and 89% on HW What about the electricity transmission losses?

OK I had the system drained down to do so other work (it was planned for summer but well life gets in the way) Work 1. London loop on the HW outlet of the tank (early days but it already seems to have reduced standing tank losses) 2. Re-pipe the bypass so it's after the CH zone valve (it was before so when I restricted the flow thro the HW tank coil it opened the damn bypass and defeated my efforts to slow down the flow thro the coil!!!) 3. Combined 22mm Feed and vent for CH (removing the old 15mm feed) - Thank You @John Carroll it's solved all the issues with air ingress and got rid of another pipe in the cold loft 4. Generally remove a load of joints (from previous versions being adjusted) and clean up the lagging 5. Convert all the main rads to TBOE with Danfoss RAS-B2 flow control TRV bodies Anyway what I needed to say was Immersion stat is set to 55 Deg C (well mid way between 50 and 60) After heating it overshot by a large margin - Tank temp at the top was 60 deg C when it cut out 1 shower later and tank temp at the top was down to 50 and the immersion cut in again Turned it up to 60 because bath night and top of the tank was nearly 70 when the immersion cut out She hadn't finished pouring the bath before the immersion fired up again top of the tank was reading 60 So I'm guessing the temp sensor is lower down the element. Can't do any more tests because the system is now refilled and I'm back on gas and I've finished lagging what I call the plant room (Others might call it an Airing cupboard) Just to be clear - the water damage on the floor is legacy from previous occupants When I replace the tank I'm probably going to replace the floor as well because it's quite crusty

I can't get a kitchen pass two nights running so this week I'm out (Cos NMR club evening is Wed)

Excellent.

Having had fun with all the permutations of pump settings on a DAB pump my only advice is to check again after a day and again after a week PP and CP on my pump initially look fine but flow rate drops over a few days - I have no clue why but the only solution for me was to go to a CC setting as there the flow rate stays constant.

If I can avoid them I will and I'll use solvent weld as much as possible but if I have no choice then that's what I try to do when I do use one. Downside of an 80's house where several people have had their fingers on the plumbing over the years

Thank you @Nickfromwales - That's certainly what I would do to add a bit of easy maintenance access when using solvent weld I also only tend to use compression/gasket waste fittings on vertical drops less chance of a leak on a vertical pipe (obviously you can't do much about P traps and bottle traps as they are all gasket type)

Just a comment....... I like solvent weld pipe far more than I like gasket fittings but when using solvent weld I always consider how I'm going to be able to either remove the section or rod / hose out the pipework in the case of blockages - washing machine powder can build up in pipe work if "someone" over doses the machine on a regular basis (I think this is amplified by cooler temperature washes). In fact the think about future access / maintenance applies to a lot of plumbing in homes.