Replacing Honeywell ST699B with a ST9400C

Sponsored Links
old prog............new prog

live..........to.......live

neutral....to........neutral

3............to.........4

6............to.........3

7............to.........1

you dont need the links on 8 and 4
 
Sponsored Links
i read with interst this thread, as I want to do the same, to upgrade my 699 to a 9400 to allow me to use boost feature to save heating costs. but looking at the photo of the backplate, I notice that i have no wire on the no7 terminal. is that normal, its one of the HW terminals. my heating and water timing works OK at the moment btw.

will wiring in the new unit but with no wire to 1 still work?

grateful for any help
 
The hot water "off" signal is used with "Y Plan" systems which have a single three port motorised valve. Yours is likely an "S Plan" system which has 2 or more two port valves. The hot water off signal is not required with this configuration.

If yours is an "S Plan" then all is well.

Welcome to the forum bigalbie. For future reference it's best to start your own thread with a new question. Adding your question to an existing thread is known as "hijacking"
 
THanks to Stem and apologies for hijacking, sounds bad...... just seemed sensible to follow the theme but thanks for putting me right.
A
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top