Biasi 24s boiler, fitting programmable thermostat

[diyphysio]

Hi,

I have a Biasi 24s boiler, i've replaced the old honeywell mechanical thermostat (must have been 15yrs old) with a Horstmann Centaurstat 7 programmable thermostat. After reading a few reviews online this sounded easy, however the boiler is not responding (firing up) to my increases in desired temperature.
the boiler has a timer clock, if set to constant then boiler works (but constantly) if not it doesnt. The old wires that were connected to the honeywell were red, blue and yellow (plus earth that was already sealed behind the stat). THe instructions for the new prog stat say refer to manufacturers instructions however dont have these as only moved in few months back.
Can anyone help??? in meantime ive put old honeywell back up....
Thanks

 

[bengasman]

Could be wired up wrong, or wired up right but programmed wrong.
Bring it back and get a proper one like Siemens. Easy to install, easy to program, good quality.

 

[diyphysio]

thanks bengasman.

its in the box ready for return today.
I dont think it was wired up wrong, however I didnt have a voltmeter tester to confirm that red wire was live, blue neutral, yellow return...
thanks for suggestion.