Hi all -
My existing programmer is a Honeywell ST9400C for CH and HW, each circuit having a motorised valve. I wish to replace it and have been offered a ST9500C. I understand this is normally used to control 2 separate heating zones, but in all other respects it seems identical to the ST9400C.
Can anyone advise if it is a simple swap with my existing programmer or do I need to make any wiring modifications? I am thinking for Zone 1 & Zone 2 I can just substitute CH & HW (or vice versa).
Regards.
My existing programmer is a Honeywell ST9400C for CH and HW, each circuit having a motorised valve. I wish to replace it and have been offered a ST9500C. I understand this is normally used to control 2 separate heating zones, but in all other respects it seems identical to the ST9400C.
Can anyone advise if it is a simple swap with my existing programmer or do I need to make any wiring modifications? I am thinking for Zone 1 & Zone 2 I can just substitute CH & HW (or vice versa).
Regards.