Honeywell ST9400C problems

[Tina Holmes]

Evening all

my husband has just installed today, a new timer unit for the CH/HW. We bought the Honeywell ST9400C. The problem
We have is that the central heating will come on no problem but the hot water makes the timer click and continuously switch on and off. Any ideas please or has anyone come across this before?
Many thanks

 

[CBW]

Please post photo of wiring and tell us what system you have: s-plan, y-plan, w-plan, c-plan.

 

[Tina Holmes]

Sorry am new here so not sure how to post photos

 

[Tina Holmes]

Think we have Y plan...hubby isn’t sure

 

[CBW]

Are you using phone, laptop iPad, other?

Double check the wiring is secure at hot water on terminal

 

[ianmcd]

Sounds like you have a Y plan and he hasnt wired in the HW off wire