Worked on quite a few yet thought that was blocking the pipework? What would replacing the hex do?
He doesn't like repairing these, a very bad repped boiler but can be fixed, for the fault you describe much less than a new one.
Where's it leaking from? Why has it started leaking? Many of these leak when moved and messed with. You may find screwing it down then full open will stop it.
Oh yes that call. I have a leaking radiator on a Sunday morning. We had a few people round last for drinks and party and it suddenly fell off the wall.
Did it?
What's Myhome? Never heard of it? Is that an existing back plate from receiver?
You might have a valve fault rather than the hive. Have to test if valve motor is getting power when hive demands.
As said then, fill to 2 bar, leave it off, check condensate for leakage.
Forgot to say, the trap will be full, so don't take that as an indication of leak.
Oh yes they do. Think about it. They close. Thus putting more leather on the system, makes boss pressure gauge go up. Bad boss.
Seriously, because I'm becoming bored of you. Search in the search button expansion vessel charge.