There are many ways to wire the CM900 to IP522, can you advise if the wire is between the two, and which end has become disconnected?
Ok depending on the wiring standard used it may be worth checking which colours where used for the terminals from CM900, the manual for the CM900 can be found here, which shows on the right hand side of page 4 what each terminal is used for (in essence there should be 3 terminals A, B and C).
Ok next we need to look at the IP522, the manual for the terminal layout can be found here.
Give me a minute to get my head round the current setup on your CM900
From what I can make out one of the two cables (black or grey) should be going to terminal 2 the other terminal 4, can you advise if this matches up to what you can see at your end?
Hi sorry, it appears I didnt get your messages until this morning.
Right, can you tell me what the other wires going to the boiler for hot water are doing (which terminals are they connected to on the IP522?