Honeywell CM921 partially blank screen issue

[Homebrewer]

Hi Guy's,

I am seeking some advice because I cannot seem to be able to troubleshoot my problem.

I have two Honeywell CM921's 1) Heating system. 2) Underfloor heating system. They are both, what I assume, paired with BDR91's. I cannot read the CM921 screen on the underfloor heating since most of the writing is blank, with just the odd line. Naturally, this makes it impossible to read or re-set. I have tried changing the batteries with new ones twice, making no difference.

My questions are:

1) If I replace the faulty CM921 with a new one. Does it need to be paired with the original BDR91 and if so how? Or do I have to replace the CM921 and the BDR91?

Cheers

 

[Dan Robinson]

Easier to replace both, but just changing the user control only requires rebbinding.

Not difficult.

 

[Homebrewer]

Easier to replace both, but just changing the user control only requires rebbinding.

Not difficult.

Could you please explain.... rebinding?

Thanks

 

[Homebrewer]

Hi Dan.... Thanks for pointing me in the right direction as I now have info on binding these stats. Which includes a U Tube video...