frustrated with CM67 room stat - help

[haf]

I am really frustrated with my room stat. I have a Worcester 30CDi boiler with a honeywell CM67NG wireless room stat. Everything works fine other than i recently noticed that the boiler was coming on at odd hours of the day and night - outside the times set on the timer. I looked around on this forum and found out about the 'optimum start' feature and follwed the advice to switch it off from the 'installers menu'. The system has been behaving better since then but it still seems to come on by itself at times - usually the night. I thought it might be to do with the fact the the CM67 has a 5 degree lower temp setting and this may be the culprit but past couple of mild nights tell me this isn't the case. I have also noticed that the heating doesn't always switch off at the time set by the timer.
The CM67 does have a temp setting aligned to both the switch on time and the switch off time (i have no idea why you would have a switch off temp setting) and i'm not sure if this has anything to do with my incorrect operation. To be honest my requirement is simple in that i just want heating to come on and off as defined by timer and nothing clever - sadly the CM67 seems to be very complex with loads of options.
I have even done a reset and 'bind' with the base unit. I am now thinking my timer may be faulty and i may just get a new one at £50.
any advice appreciated

 

[fitz1]

your only setting temp at times , not on and off.six temp settings during 24hr. boiler will come on if cm67 temp setting asks for it.

 

[bobw1956]

Set your off setting temps; to 10 deg;
IE; on 6.30 temp 22 deg off 8.30- 10 deg;
on 12 temp 20 deg; off 2.00- 10 deg;
on 4.30 23 deg; off 11am-10 deg;
Great bit of kit, it,s not faulty,try the above and let me know the outcome

 

[haf]

thanks bob,
I will set 'off' temp to 10 degrees and see what happens.

fits,
I think i understand what you are sayng i.e I'm not actually setting temp as on or off but just saying at time x get temp to level a and at y time get it to level b and so on for 6 settings. So if i want to simulate an/off then i should set the 2nd time to the minimum poss i.e 5 degrees. I would assume that if temp got to below 5 overnight then boiler would kick in until its 5 degrees.

It all makes sense as soon as you stop thinking about the programming as 3 sets of on/off but 6 sets of 'get to this temp'

Fingers crossed that the boiler now starts coming on/off at sensible times.