Boiler won't fire up

[trap125]

I have an Ideal Mexico Slimline 2 R55 and I'm having a few problems. From the electronic timer the heating will only come on if HW and CH are selected. In the past it was possible to turn the CH on by only selecting CH.

It's been very cold recently & I tried leaving the heating on overnight. The radiators get hot for a while but then they cool down, in fact go cold. I looked at the boiler and the pilot light was still on. I've tried adjusting the thermostat on the boiler and sometimes - if the system has been off for a while - it will make the boiler fire up.
I guess what I'm trying to say is that I can't keep my heating on if I want to, the boiler switches its self off even though the control is set to on. Also 2 of the 8 radiators never really get hot and a few get very hot. I always seem to hot water.

If anybody has any advice on how to sort this out it would be much appreciated as I'm very cold at the moment!

 

[75pete]

Have you hot water? If so when you use it and the boiler fires up does your rads also get hot? have a look at the 3way valve if you have one.
Also see FAQ3

 

[trap125]

I've got hot water. Indeed, when I use it the boiler fires up and the rads get hot.

Where might I find the 3 way valve and what does it do?

 

[jackthom]

It's likely to be close to the boiler/pump and it determines whether the hot water from the boiler goes to the radiators, to the HW tank or to both.
It can also prevent the boiler from firing up if the switches inside the valve are worn out or the valve is sticking.

The FAQs near the top of the plumbing forum will tell you more about it and how to keep the central heating going until you can get someone out to have a look at it. http://www.diynot.com/forums/viewtopic.php?p=243656#243656

 

[trap125]

Many thanks for the help and advice. Much appreciated.