Hot Water only coming on when heating switched on first

[Tryingit]

My parents have recently moved house, their boiler looks fairly new and was recently serviced. It's not a combi.
They are only able to get the hot water to come on by first switching the heating on. They are then able to switch the heating off and the hot water remains on until the switch it off again.
The valve moves across when the heating is put on, does not move then the hot water goes on, it moves back when both are off.
Thank you

 

[Hugh Jaleak]

Sounds like a wiring fault, if you are not comfortable with testing and fault finding on main electricity, then advice is I'm afraid to find an Electrician who is familiar with heating circuits and let them test and diagnose. You never know what's been done before....

Artisan Electrics on You Tube, he was testing in a Domestic Property and found someone had wired the heating system up with two power supplies, resulting in a 13A Plug in the Kitchen having Live pins when removed from the socket!

 

[Tryingit]

Thank you, we had a feeling it was a wiring fault rather than the valve. What a pain! Thank you for replying.

 

[CountryFan]

If it’s a 3 port mid position valve, it doesn’t move for hot water only.

 

[Tryingit]

If it’s a 3 port mid position valve, it doesn’t move for hot water only.

Thanks, so does it sound like the valve is behaving as it should?

 

[gas112]

put a pic up of the valve

 

[Tryingit]

Does this help? Can get more if needed. Thank you