Since turning the heating back on our hot water has cooled down to minimal heat and the radiators do not get hot at all even when the stat is turned up full, boiler was checked over when heating was put back on as it wouldnt light shortly afterwards, this was the fan and now it lights no problem, heat was a problem before this but as weather was still ok we did not realise until after the engineer had left so couldn't ask him! boiler is fine and the pump feels as though it is working as it does slow down when turned to a lower speed and hums quietly. heat in the pipe before and after the diverter valve is the same (not hot at all) so I don't think it is this, hot water does get properly hot when immersion is switched on though. Could this be faulty tank stat or room stat? or both? What I can't understand is if one of the stats are faulty why is it affecting both hot water and rads? the boiler is an ideal and is only 4 years old, pump, stats, diverting valve are all also only 4 years old, timer seems ok. system has a cold water feed to a tank in the loft and all rads have been bled to no avail, any help will be appreciated.

Zeebra3, October 2008

We finally had the boiler man look at the boiler and he found a small circular thingy (tube like) which was faulty, apparently they don't often go but it was stopping gas getting through to the boiler after the initial burst and then cutting it off. A warm house and hot water at last! best of it was the part was only £10 and total price fitted was a very reasonable £47.
Thanks for your help though Robin.

Zeebra 3, October 2008

Have made a few more checks tonight, and after turning off the room thermostat the pipes got extremely hot around the pump and the water started to warm up but after 10 minutes the boiler went out and the pipes started to cool down as if the system had switched off with the pump still running (and the boiler fan) I am at the point where I am considering forking out for the plumber again, he's good but not cheap!!! It could be the boiler stat as if it was only on one and stuck there I would expect it to turn off whilst lukewarm, you might be right, shame I cannot open the boiler to check it out!!

Zeebra3, October 2008

I am still guessing... If the manual heat control on the boiler has no effect on the temperature of the hot water - i.e it remains on the cool side even when you crank it up to maximum - surely you are close to a diagnosis. I can use the same control on my system to get the water very hot indeed - uncomfortably hot - which is why I keep it on a middle setting.

The boiler's thermostat - the control that goes from 1 to 6 - is defective! It's permanently operating at level 1. Can there be any other cause?

Robin, October 2008

Hi Robin

Yes it has a knob on the front and goes from 1 - 6 unfortunately it was one of the first things we looked at and have tried it on 1, 3 and 6 to no avail, the manual says it should be on six. I just hope we can sort before the weather gets really cold!

Regards
Zeebra3

Zeebra3, October 2008

Look to your boiler - it's a common fault that affects both hot water and heating water - neither is getting hot enough. The boiler has recently been "serviced" and has, or common sense says it should have, a user-adjustable temperature control - there's one on my boiler - it sticks out the front and is set mid way between 3 and 4. It tells the boiler how hot I want it to heat the water - do you have this control? Is it hidden behind a panel? Have you adjusted it?

I am not an expert - just guessing.

Robin, October 2008