Our Honeywell evohome Frequently Asked Questions are normally quite technical in nature so we will list these below. Firstly, please read Honeywell's evohome Frequently Asked Questions page to see if your answer is here. If once you have read all these FAQ's and you still cannot find the answer you are looking for, please Contact Us and we will do our absolute best to give you the answer you are looking for.
Our most recent FAQ's are:
1. Why is my evohome Controller is showing a 'COMMS FAULT'?
2. Why does the BDR91 Wireless Relay Box controlling the boiler turns ON & OFF frequently?
3. How do I unbind and rebind a device on the evohome Controller?
A 'COMMS FAULT' is indicating the evohome Controller is not receiving a signal from the device it is reporting. This can be due to several reasons, however the main reason is normally that the evohome Controller was not bound correctly to the other evohome device in the first place or that the evohome Controller or the evohome device is being affected by interference from another RF device or the devices are poorly located. The first steps would be to test RF signal strength between the evohome device with the 'COMMS FAULT' and the evohome Controller using the 'System test' section of the evohome Installation Guide (from page 29 onwards). If the RF signal tests are showing 'poor' signal, then you need to improve this by possibly relocating the evohome Controller and trying again. If it is showing 'good' signal, then look for the problems the equipment could be facing while trying to transmit an RF signal. The last resort is to rebind the device or zone that the 'COMMS FAULT' is occurring on - this must be done thoroughly (complete unbind of the devices) and rebound with care to ensure you do not cause the same issue again.
The evohome system uses TPI (Time Proportional & Integral) control. The evohome system will not wait for your room to go cold before heating it back up and instead evohome will learn the zones it controls and will want to ensure these remain comfortable. To do this, the evohome system uses an advanced control system that anticipates load/demand before the room temperature drops and adds the required amount of energy to that particular room. While the setpoint for the heating zone is within the 'Proportional Band', this can result in the BDR91 Wireless Relay Box that controls the boiler turning ON & OFF at regular frequent intervals. This is perfectly normal and is the way TPI thermostats ensure the room temperature does not get too hot or go too cold. More on TPI control can be downloaded in a couple of PDF documents created by Honeywell here - http://www.honeywelluk.com/documents/All/pdf/FAQ%20TPI%20Control.pdf & http://www.honeywelluk.com/documents/All/pdf/TPI%20Functionality%20explained.pdf
Rebinding a device (CS92A, HR92UK, T87RF, etc) on the evohome Controller needs to be done with care and failure to unbind and rebind the device correctly will cause issues. Please head to our evohome Forum (https://theevohomeshop.co.uk/forum/) where there is help and advice on binding evohome items correctly.