Worcester Boiler sometimes doesnt come on

[Ladywarrior]

Hi there

This is literally just it, we put the programme to be on at the same time every day, and sometimes it doesn't come on.

We then have to put the whole system on(radiators as well!) to get hot water. Anyone had this issue? Anyone know what it might be?

Thanks as always!

Its not just because thermostat is set too high is it?

Hiya!
Ok please forgive my ignorance! Which themostat are you talking about? It's our hot water that sometimes works and doesn't, we don't have any issues with the radiators however.

Thanks!

Ah I didn't read it properly sorry I thought the room temp thermostat was set too low (not high! Gah!). But clearly not relevant if its just water -unless the water thermostat is set incorrectly?

Call the Worcester Bosch helpline. They are usually really helpful and will tell you if it sounds like a fault or something like I did (not topping up the system after bleeding the radiators).

If you have noticed sporadic changes in water pressure due to water company work or leak on the street worth asking if this is causing the issue.

what colour is your hot-water cylinder?

post a photo of your programmer, thermostats, and the pipes and other things around your cylinder and the boiler.

It might be the 3 port valve, which is operated by the thermostats and timer, and contains a switch to start the boiler.

OP, I have one of these boilers it's about six years old so not sure if they're similar but I don't set mine. Can I ask you what you're setting?

I have my thermostat set at 15 degrees just now, which of course this weather the radiators don't come on. Turn on the hot taps though and the boiler comes on automatically to heat the water. Sorry if I've got the wrong end of the stick.

Good morning!

Thanks everyone. Here are some pics, it's a white cylinder and two port valve.

it's might be the valve. Though not as sure as if you had one three-port rather than two two-ports. Can you show us, or is it inside the boiler case?

Turning on the CH would move a valve, but would not affect the HW thermostat. If the thermostat and the valve were both working then the pump and boiler should start regardless of whether it was CH or HW calling.

If it previously worked correctly and now doesn't, it's unlikely to be a wiring error.

It might possibly be a control or electronic fault in the boiler. Either way you need to call your qualified mender. You should get someone who is G3 qualified to work on your white cylinder as well, in case the fault lies there, though that may be less likely. Your ACL Drayton programmer is an old design, but pretty reliable. Very easy to swap for new if necessary. Has it been hit, moved, or had water or tea run over it? I see a mark on the left-hand side.

That boiler looks the same as mine, Not the thermostat though. Have you opened the door/flap at the front OP? See what's going on with those controls and water pressure.

First of all thank you all so much for your replies. Yes the Drayton unit has been moved and there is a bit of plaster on it. Have opened the from and so far the pressure has been fine. Its been a crazy day sorry for not getting back to you sooner been full on day. Will get hold of a G3 qualified person. Piglet John how do you know so much of this thing???

if the programmer has been moved, there's probably a bad connection in it.