I worked it out in longhand, as I have a larger than normal bath I ended up with a 1200x450 cylinder. (assuming that I fill the bath with 2/3 hot and 1/3 cold and that only 2/3 of the cylinder is heated). It's actually more than I need, in practice there's enough for a bath plus a couple of...
I have a relatively new (vented) cylinder and it will keep hot for days if I don't draw any water off. So the standing heat loss from the cylinder is quite low. Also any heat lost will help warm the house in winter.
If you get a combi, you'll be cursing it when it breaks down (which it...
One test it may be worth doing is to pour bleach down the overflow, if the overflow is manky. If it's icky inside it can release a blast of 'sewer gas' when you pull the plug. But the fact your washing machine is backing up points to a blockage downstream.
Trouble is the plastic can 'creep' over time resulting in leaks. I think you have three options, replace with push-fit, do it in copper, or monitor periodically.
If there is a slight trickle getting past the sealing washer at the bottom of the flush valve, the water level in the cistern will drop. When it drops low enough the fill valve will add a little water to bring the level back up again.
Flush valves are usually a bayonet fit so you could undo...
+1 to that. I avoid Sunvic like the plague.
My recommendation would be a Drayton LP722 or MiTime dual channel programmer, depending on how much 'bling' you want, but opinions will vary.
I would say that the as the radiator has given up only half of its heat, the boiler will have to add only half the heat when that 'packet' of water next gets reheated. I would posit that the radiator in isolation is 100% efficient, but that the boiler and pump will use more electricity if the...