Turning on hot water tap, and the radiators gets hot!

[adamsinfo]

All, have a bizarre issue that would appreciate guidance on.

Over the past few weeks, I have noticed the shower getting slightly colder and colder despite being on full hot setting. I have also noticed the radiators getting warmer for no reason because the heating is not on nor has been on all day.

Yesterday, I run the bath, and push it as far over to the 'hot' side as it goes. The water is freezing but the radiators are getting boiling hot!

The boiler itself seems fine. By default it rests with a '0' on the display. When I turn the heating on, a 'c' appears and it kicks into action with the radiators getting hot quickly, as it should. When I turn the heating off, it returns to a '0' after about 30 seconds. When I turn the tap/bath/shower on, a 'd' appears, as it should, but as I mentioned, the radiators start getting hotter and the water is freezing cold.

I thought I may have knocked something by the boiler so I messed about with a few of the pipes/stopcock/visible valves/etc, and then set them back to where I found them. I did open one valve that seemed to sit on a flexible pipe between a hot and cold pipe. This made all the pipework shake as if the building was going to fall down so I quickly set it back.

Anyway, problem solved, but I'm going to guess that this is a temporary fix, and that this is going to recur at some point. Where do I start?! My unqualified guess is that the [automatic?] value that decides where the hot water goes is stuck/sticky/worn out. Is there such a thing? Where would it be?

Thanks!

Adam

[htg engineer]

Diverter problem - either valve or motorised head - without boiler make and model that's all the help I can give.


htg

[adamsinfo]

Thanks! It's an IDEAL isar he24. Is this something I can do myself or do I need an expert?

[pmarco]

After reading Adamsinfo review, I have the same problem!
I have replaced the actuator, but problem remains.
Is the valve body assembly the next thing to change?
A friend suggested the PCB could be the fault, any ideas?
Continues to be more costly the more things you have to replace!

thanks for your help

[chris_on_tour2002]

sounds like the diverter valve, i'd say that it's not a job for a DIYer. you may think that you are saving money but could prove way more costly in the long run.

the flexible pipe between the hot and cold pipes (actually between the mains feed and return on the heating side) is the filling loop. you only need to touch this if the pressure in your system needs topping up, otherwise don't touch it. it won't solve your problem.