Need help wiring a new digital thermostat

[marc1977]

OK,

so i swapped the broken stat for a nice new honeywell programmable thermostat and wired it up as you all suggested. It works fine EXCEPT it does not switch off when the old honeywell timer in the boiler cupboard upstairs has the CH set to off. In theory I guess this is not an issue as it can now be controlled by the new stat. This is related to hails post below:

"Is the live coming directly from the CH ON terminal of the Honeywell timer? If so, you have two timers in series; you only need one - the Digistat. There are two ways round this: (a) Set the Honeywell timer to Continuous; (b) move the connection from the CH ON terminal to a permanent live terminal. Method (b) is preferable."

it seems i have created method b) in my setup. Is this OK? Whats the best practise in these situations? I cant remove the old honeywell timer as it controls the Hot Water as well as Central Heating?

Thanks as always!

Marc

 

[D_Hailsham]

it seems i have created method b) in my setup. Is this OK? Whats the best practise in these situations? I cant remove the old honeywell timer as it controls the Hot Water as well as Central Heating?
If you have used method (b), the heating side of the old timer has been bypassed, so it won't have any effect. All it will do is control the Hot Water times.

Heating times and temperatures will be controlled by the CM907.Don't forget that if you want to turn the boiler off (say overnight) you need to have a low temperature for the last setting of the day, e.g 2300hrs = 10C.

 

[marc1977]

thanks hailsham.

BTW it turns out i "welded" the relay in the old timer box to ON when i blew the fuse...hence why it is always on now! however this works just fine so i am goign to leave it alone now!

marc