Gas Vitodens Boiler not firing up

[talksr]

Hi there,

I would be really grateful if anyone can help me with the following.

We have a Vitodens 100-W WB1B 26kW gas boiler with a Honeywell ST9400C programmer which seems to be playing up.

The hot water appears to be hot at the times it should but now the nights are getting colder, I am noticing that the boiler is not firing up when it should for the heating. I have set it to come on for heating between 3.30pm and 8pm, however it seldom heats the radiators. I find if I turn off the power to the entire central heating system and put it back on, the boiler fires up and within minutes the radiators get warm.

At the moment, I have the programmer set to cont for heating, so it should be on constantly. The thermostat is set to 25 degrees and is currently picking up that the room is around 15 degrees, but still nothing from the boiler. If I twist the thermostat between on and off, nothing.
If I go back and shut the entire system off and put it back on, the boiler will be on, the thermostat will have the orange heating light on and all will be well, but within five minutes, its all gone off again.

Attached are some images of the boiler as it currently appears.
I am in a housing association property, so not my responsibility if there is a fault, but I would rather not call someone out on an errand if it is something simple I can sort.
Any ideas?

 

[muggles]

If your hot water is working but your heating isn't, you've either got a dodgy motorised valve or a dodgy programmer (there was a bad batch of ST9400Cs a while ago). Either way, something your HA needs to sort I'm afraid

 

[talksr]

If your hot water is working but your heating isn't, you've either got a dodgy motorised valve or a dodgy programmer (there was a bad batch of ST9400Cs a while ago). Either way, something your HA needs to sort I'm afraid

Thanks for your reply. There is nothing else I should check?
Have not had gas central heating before, so not sure if there is anything I am missing, but I have checked all of the main things I can think of.

 

[muggles]

Sounds like you've done all you can I'm afraid, leave it to the people who are paid to look after you!

 

[talksr]

Sounds like you've done all you can I'm afraid, leave it to the people who are paid to look after you!

Interestingly, if I turn up the thermostat on the side of the hot water tank, it clicks and immediately the boiler comes on.
Will give them a call tomorrow and see when they can slot me in.

 

[Jackrae]

Minor point, but your CH system pressure is a bit low

 

[talksr]

Minor point, but your CH system pressure is a bit low

Any ideas what might cause that?

 

[muggles]

A leak, air escaping through an automatic air vent, flat expansion vessel causing water to dump out of the PRV, faulty PRV...all things you can ask your engineer to check when they come round