In taking off my old Danfoss programmer and wireless thermostat receiver I found a rats nest of wiring. It seemed to be a non standard S plan arrangement, it clearly worked in that the configuration but was not easily mappable into a Gen 3 Nest.
The setup is:
Alpha CD24R Condensing Boiler
2 x 2 Port Valves (HW and CH)
Pump (Powered from Boiler)
Hot Water Cylinder with Stat
Boiler Wiring:
Live/Neutral Feed
Switched Live (Grey)
Channel 1 On (Black)
2 Port Valves:
Orange Wires bonded and linked to the boiler Ch 1 On (Black)
Grey Wires Bonded and linked to boiler Switched Live
Brown and Blue bonded to Live and Neutral feed respectively
The Stat Wiring I can't remember but I could only map directly into the Nest 3 and 6.
I bonded the 2 port valve greys and linked to ports 2 and 5 on the nest but got nothing.
I then bonded a direct Live feed into the 2 port greys and could get them to actuate but the boiler wouldn't fire.
It's at this time point I lost my rag and opened the boiler to check the wiring colouring and assignments. I suspect its not correct but I've managed to get it all working with some rewiring.
I've decommissioned the Boiler Ch 1 On black wire. It doesn't seem needed? Certainly not from S Plan diagrams I've seen. Does that sound reasonable? Is working without it so I can't envisage what purpose it would serve.
I've kept the 2 port valve oranges bonded and connected to boiler switched live (grey).
I've kept the 2 port valve greys bonded and then linked to 2 and 5 on the Nest. I've also kept a direct live feed (Brown) bonded onto the greys. The S Plan wiring indicates this would ordinarily be taken from the boiler but I'm not sure how that's achieved with what I have.
The ports actuate as expected with CH and HW demands and the boiler fires / pump runs. I can't see what could go wrong wrong with the Boiler Ch 1 On wire decommissioned but I'm not an expert....
The setup is:
Alpha CD24R Condensing Boiler
2 x 2 Port Valves (HW and CH)
Pump (Powered from Boiler)
Hot Water Cylinder with Stat
Boiler Wiring:
Live/Neutral Feed
Switched Live (Grey)
Channel 1 On (Black)
2 Port Valves:
Orange Wires bonded and linked to the boiler Ch 1 On (Black)
Grey Wires Bonded and linked to boiler Switched Live
Brown and Blue bonded to Live and Neutral feed respectively
The Stat Wiring I can't remember but I could only map directly into the Nest 3 and 6.
I bonded the 2 port valve greys and linked to ports 2 and 5 on the nest but got nothing.
I then bonded a direct Live feed into the 2 port greys and could get them to actuate but the boiler wouldn't fire.
It's at this time point I lost my rag and opened the boiler to check the wiring colouring and assignments. I suspect its not correct but I've managed to get it all working with some rewiring.
I've decommissioned the Boiler Ch 1 On black wire. It doesn't seem needed? Certainly not from S Plan diagrams I've seen. Does that sound reasonable? Is working without it so I can't envisage what purpose it would serve.
I've kept the 2 port valve oranges bonded and connected to boiler switched live (grey).
I've kept the 2 port valve greys bonded and then linked to 2 and 5 on the Nest. I've also kept a direct live feed (Brown) bonded onto the greys. The S Plan wiring indicates this would ordinarily be taken from the boiler but I'm not sure how that's achieved with what I have.
The ports actuate as expected with CH and HW demands and the boiler fires / pump runs. I can't see what could go wrong wrong with the Boiler Ch 1 On wire decommissioned but I'm not an expert....
