Hot water off but water still hot.

theoretica

I suspect this is the answer:

Bendy_House said:

The other most likely possibility is that the motorised valves are faulty (these are the silver things above the red pump, and below/in front of it). So, when the CH is on - heating your radiators - some of the boiler's hot water is also getting through to heat up the hot cylinder when it shouldn't be.

Which will take the landlord to get someone in to sort out - worth doing as you want your heating running as efficiently as possible and not heating the water hotter than you intended.

Louscorp

I just googled the instruction manual for the boiler (EP2001) control pad and in one section it says this:
"The programmer has an electrical interlock to protect simple central heating systems which can only heat the radiators when the hot water is also on. If yours is a simple system, the electrical interlock will automatically cut out the programming facilities that your system cannot cope with. This means that the hot water is automatically turned on when the central heating is on."
Maybe this is the reason??

Bendy_House

Louscorp said:

I just googled the instruction manual for the boiler (EP2001) control pad and in one section it says this:
"The programmer has an electrical interlock to protect simple central heating systems which can only heat the radiators when the hot water is also on. If yours is a simple system, the electrical interlock will automatically cut out the programming facilities that your system cannot cope with. This means that the hot water is automatically turned on when the central heating is on."
Maybe this is the reason??

Blimey!

That would be unusual, especially since your hot cylinder has a 'stat stuck to its side. That suggests it will shut off the heating to the cylinder once it's hot enough.

Looking at that wonderful photo you posted, I can see - with near 100% certainty - that your DHW is completely separate from your CH. I say this because you have TWO motorised valves - the rectangular silvery things - and these are what control the boiler's flow to the CH and DHW.

A photo of your timer/programmer would be useful at this stage.

Anyhoo, I wonder if it's just that your cylinder is well insulated, so - once heated - it stays hot for a couple of days?

Bendy_House

What you've said about your immersion switch is pretty conclusive - if it sizzles when turned on, and stops when offski, then it's pretty certain that leaving that switch in the 'up' position means the immersion is 'off', and amen to that. Leave it there

Louscorp

Here are the boiler controls! 

Louscorp

Bendy_House said:

Louscorp said:

I just googled the instruction manual for the boiler (EP2001) control pad and in one section it says this:
"The programmer has an electrical interlock to protect simple central heating systems which can only heat the radiators when the hot water is also on. If yours is a simple system, the electrical interlock will automatically cut out the programming facilities that your system cannot cope with. This means that the hot water is automatically turned on when the central heating is on."
Maybe this is the reason??

Blimey!

That would be unusual, especially since your hot cylinder has a 'stat stuck to its side. That suggests it will shut off the heating to the cylinder once it's hot enough.

Looking at that wonderful photo you posted, I can see - with near 100% certainty - that your DHW is completely separate from your CH. I say this because you have TWO motorised valves - the rectangular silvery things - and these are what control the boiler's flow to the CH and DHW.

A photo of your timer/programmer would be useful at this stage.

Anyhoo, I wonder if it's just that your cylinder is well insulated, so - once heated - it stays hot for a couple of days?

Image provided

Bendy_House

Ok...

Looking at your valves:

The two silver things, 1 and 2, are motorised valves. These are opened by the boiler control you posted a photo of.

When the CH says 'on', then valve '2' goes whirrrrr and opens, and this then turns on the boiler and the pump. The pumped water goes upwards from the red pump, along that horizontal white pipe and down through the open valve and off to the radiators.

When your DHW says 'on', then valve '1' opens and the same thing happens - the pumped water goes up from the pump, through valve '1' and in to the cylinder 'coil' (where you can see some green surface corrosion - now't really to worry about).

When both CH and DHW are on, then both valves will be open, so the pumped water will go through both circuits. When the CH and DHW are 'off', then the valves close, and the boiler and pump shut off too.

The boiler controller you've shown just says 'on and 'off', and the actual temperature of the CH and DHW is then controlled by the Room Stat and the Cylinder Stat respectively. So, once your house is warm enough, the room stat says 'off' and the CH valve closes and the boiler goes off, even if the 'control/timer' says 'on'. Ditto for the hot water; when the cylinder reaches 60oC - what the 'stat is set to - the stat tells the DHW motorised valve to close and this shuts off the boiler and pump - even if the DHW timer still says 'on'.

That's how it should work.

You can see all this in action; with the timer 'off', the valves will be closed and the boiler and pump off. If you now stare at these valves and someone turns on the heating (eg turns up the room stat when the timer is saying 'on') then you should hear an immediate whirrrr and 'click' coming from valve 2. The pump should then fire up, and the pipes going to the valve should get hot pretty quickly. When you turn the room stat back down - or turn off the CH timer - the valve should whirrr again and close, and the pump stop running.

Ditto for the DHW valve '1'; if someone turns on the DHW timer and the cylinder stat is also asking for heat, then valve 1 should whirrr and click and the pump come on. The pipe coming from valve 1 to the cylinder should get hot pretty quickly. If you turn off the DHW timer or if the cylinder stat says "I'm at 60oC", then the valve will whirrr again, close, and the boiler and pump stop running.

See the wee lever arrowed '3'? That is used to open the valve by hand (for things like filling your system - don't worry about that). It can also tell you IF the valve is open or closed. If you try and move it by hand and it's firm and won't move (tho' it will if you push firmly, and it'll then return when you let it go), that means the valve is closed. If it's loose, and can be moved from end to end 'floppily', that means the valve is open. You can try that by pressing on it with the valve closed - CH off - and then turning on the CH and seeing how loose it's become.

Ok, something to try: with the boiler off for a while so that these pipes around the pump and valves aren't too hot, try these levers on both valves - check that they don't move easily at all - ie they should both be closed. Now turn on only the CH. The CH valve '2' lever should become 'floppy' and the pump fire up.

Check the lever on valve 1 - that should still be firm, valve closed. Is it?

Pretty soon the pipes to valve 2 will be hot to the touch as it should be. But also try the pipe from valve 1 to the cylinder - is that getting hot too? It shouldn't be (but I suspect it might...)