Honeywell CM61 Thermostat 'auto' issues

[greenie]

This is my first post on here, i've found some very useful info and am hoping that someone will be able to assist me.

I have a feeling that this is a very stupid question, with the answer staring me in the face, however i have read instruction manuals and searched the web for answers and still cannot figure it out.

Honeywell CM61 Thermostat:-

Manual mode works fine and auto mode works fine....to an extent.

Below shows the programmed times (auto) i currently have set:-

Prog 1, Auto, time set at 06:30 (22C) - boiler starts
Prog 2, Auto, time set at 08:00 (5C) - Boiler switches off

Prog 3, Auto, time set at 19:30 (22C) - boiler starts
Prog 4, Auto, time set at 22:30 (5C) - boiler switches off

Prog 5, nothing set, display shows - - - - - - -
Prog 6, nothing set, display shows - - - - - - -

The boiler has been auto starting anywhere between 03:00 / 05:00, yet these times are not programmed...
For some reason the boiler auto starts early morning, in between the set times. It doesn't just come on and go off, it comes on and has been staying on until i have to override it by pressing 'off'. Could this be something to do with the temperatures i have set ? or the programmed times etc ?

The boiler was installed about 10 weeks ago, Worcester Greenstar 30. All auto times have been working fine upto now, daytime auto times are ok, its just the morning that seems to be a problem. I Have not used any auto times for about the last 4 -5 weeks. But now the weather has changed i have auto times set, and its been the past few days this problem has been occurring.

Any advice or info would be much appreciated.
Cheers
marc

 

[simond]

I suspect this is the Honeywell Optimum Start function.

We have had similar issues with this a couple of years ago, thought the customer was mad; however, a call to a nice lady at Honeywell resolved it.

Optimum Start is meant to learn how long it takes your house to get from cold to hot - which is easy to do, when you think about it, as it has all the information to hand. It then calculates the latent time to reach your target temperature at a particular time of day, and advances the 'boiler on' period so the temperature is reached by 06:30 (in your case).

This is all fine and dandy in principle, but it seems the software is not infallible.

The nice lady at Honeywell in 2004 was explaining that she had a CM6X and it worked beautifully. Then she blabbed a bit further and said that hers came on a 3am sometimes, so she fixed it by changing the 'on' period to 10.00

So, the simple answer to your problem is to access the second level menu and turn off Option 14 - Optimum start.

We nobble all our CM6 series stats when we install them to stop customer experiences like yours.