Wiring is not my strong point. A customer with an open vented boiler has hot water but no heating. I suspect the danfoss 3 port valve. There are 4 wires: orange (switched live), grey (hot water off), brown & white (heating on) and blue (neutral). I was expecting the orange to become live once the valve had moved to the heating position but that’s not the case. It does become live and fire the boiler when hot water is selected. Am I right that the orange should become live when either is selected? The black wire on the left is the 3 port. Thanks!
Thanks. The brown/white wire becomes live when the programmer calls for heat so it must be a fault with the valve, right?
Brown/ white wire ? There should be blue ,green/ yellow ,white, grey ,and orange ( 5 in total) from MP valve to wiring centre ??
hi. if it helps, i put this drawing together, (leaving out neutrals and earth, for clarity.) how y plan works good luck peter
Thanks for that, Peter. I assume the orange will serve the same purpose with the different Danfoss wiring.
also im not sure but the valve you have, may not be spring return. its powered both ways, is it hot water priority ? or flow share, ? this diagram is for spring return, but should help figure it out
The brown & white gets 240v when the controller calls for heat. Then what? I'd normally expect the orange to become live and connect to the boiler switched live but the diagram suggests the orange is just HW.
HSA 3 is mid position spring return. The orange will be live in HW only by backfeed from cylinder stat. Only other thing to check is that the grey wire is live when heating only selected.
Thanks for that - looks like the setup they have. Would you agree that the grey wire out of the 3 port should become live if the valve is working properly (when the brown/white call for heat is live)? Looking at the diagram, the grey doesn’t seem to go anywhere other than link to the cylinder stat off via the broken black line. What would trigger the boiler?
The grey wire is a live feed to the switch in the actuator. normally this is fed from the HW off terminal in the programmer and the satisfied contact on the cylinder stat. When HW only is selected, the orange will be live as it is backfed from the boiler/pump connection that is fed from the cylinder stat demand contact.