Honeywell ST699

[llionevs92]

I have recently moved into a house with a very old honeywell control panel, st699 or st799, everytime i set the clock for the automatic timer it resets to 00:00 after a few hours, have looked into fitting a replacement, the ST9400c, is this a straight forward job? Im confident enough with wires just not sure if they go in the same place on the replacement, thank you

 

[RandomGrinch]

The ST699 has a few more terminals on the backplate and will also have some wire links between L and terminals 5 and 8...

These aren't required on the ST9400C, as the links are built in to the PCB.

The terminals have also moved..
CH on has moved from terminal 3 on the ST699 to terminal 4 on the ST9400C
CH off, from 4 to 2
HW on, from 6 to 3
HW off, from 7 to 1

It should be a straightforward swap.
If you want to post a photo of the wiring on the ST699 backplate, we should be able to confirm.

Although it is worth mentioning, there are a load of alternative and smart thermostat options available, if you want to upgrade from the ST699.

 

[llionevs92]

Thank you very much, will get back in touch with photos soon, got a baby on the way in november and would love to get the heating on a timer, very grateful for your help