Y plan provides HW & CH irrespective of request, turn of the power and

[GeoffG1]

I have replaced a danfoss timer /switch on a older system to a Drayton LP522 which consist of a hot water cylinder (heater not working) with a cylinder stat. A Honeywell y plan 3 port, a pump and a back boiler but no thermostat. I have checked and checked the wiring and all seems correct but… no matter what you ask for from the programmer you get both HW and CH. The motorised valve moves on its own and has resistance when the power is off but when on it is movable without resistance, turn of the power and it resets to AB again. Any thoughts please?

 

[Deleted member 120897]

Do you mean the programmer selects them both? Is it set to a gravity system?

 

[GeoffG1]

Do you mean the programmer selects them both? Is it set to a gravity system?

I tried that through moving the dim pin and it demanded both. When back in pump position then it does them separately. Its at the 3 port valve I think, it doesn’t select either CH or HW it seems to default to the AB position.

 

[Deleted member 120897]

It should default to HW, so there’s a chance you have got a wire wrong. Can you post a photo of the wiring? If you have a fully pumped system, then the Drayton will need to be set to that.

 

[GeoffG1]

Drayton set to pumped. I am going to replace the connection box and tidy it all up as this was done a long time ago and not good enough. The new part is the Drayton.

 

[Deleted member 120897]

I could be wrong, as I’m not 100% on wiring, but I don’t think you’re supposed to have a live link to hot water off. This usually comes from the cylinder satisfied.

 

[EvilDrPorkChop]

Yeah you don't need the link in from Live to HW off. Although that may not be your problem, that's certainly wrong.

 

[GeoffG1]

Thanks, will drop that one out when doing the rewire. We may have hit on the issue from watching a YouTube video. The 3 port valve has a override switch on the side it was set to Open Manual rather than auto. The video suggests it stays in in last setting. I powered off and moved it to auto, turned it back on the we can now get separate heating and water.