Honeywell replaced to Hive

[johne999]

Hi all - hoping for some sage advice.I have a R6660D and ST9400C installed with a normal boiler, I want to install my Hive 2-ch controller for CH and HW.

I can pretty much figure out the CH wiring, correct me if I am wrong, but the Hive replaces the R6660D receiver, but the HW is a mystery. There is a junction box with connections for the boiler, HW pump, receiver and timer, but I cannot work out if this is a standard arrangement or a unique install.

Any guidance appreciated.

 

[RandomGrinch]

I can pretty much figure out the CH wiring, correct me if I am wrong, but the Hive replaces the R6660D receiver,

Not quite, the Hive receiver would replace the ST9400C - the connections for the hot water and heating are behind there.
The R6660D would then be linked out, by moving the brown wire in terminal 4 of the wiring centre to terminal 3 - the entire R6660D and its cable could then be removed.
Show us a picture of the wiring behind the ST9400C, and we should be able to advise further.