Heating only coming on with Hot Water

[pabs83_]

Hi everyone,

Have had a problem last few months with radiators only heating up when hot water is on.

I've had the 3 way valve replaced twice and had electrics checked but it's still the same.

When the heating only is on, the boiler does sound like its firing up but it's not heating up the rads. I can hear it clicking off/on if I turn the thermostat down/ up but it doesn't make a difference. The heating engineer I've been using is stumped and basically gave up. Dont blame him tbh.

It's an old Ideal boiler that should probably be getting replaced soon but this feels more of a controller type issue.

Does anyone have any idea what I can do to fix this or what it could be?

 

[ianmcd]

post pics of what you have, mid position valve programmer, room thermostat boiler etc we need more information

 

[Alec_t]

Have had a problem last few months with radiators only heating up when hot water is on.

What changes, if any, have been made at the start of that period to the system and which could have triggered the problem?

 

[pabs83_]

Attached pics

 

[pabs83_]

What changes, if any, have been made at the start of that period to the system and which could have triggered the problem?

None that I can think of. Everything pointed the 3 way valve.
It was a Drayton replaced by honeywell originally, would that make a difference?

 

[pabs83_]

This is the old one that was originally replaced