Turn evohome screen off completely

[bruce_miranda]

I have my evohome screen set to minimum brightness and even then its too bright in the night.

Is there an option to turn the backlight or screen off completely?

[SplanK]

I don't think there is a way as I had the same issue.

However I have learnt to live with it, and set it to night mode 24/7 which helps.

[DBMandrake]

There doesn't seem to be any way to turn the screen off completely, either manually or as a screensaver, even when running from battery power.

Considering that if the unit is left off the charger by accident and allowed to run flat (about 5 hours) your heating system will stop working entirely (unless you have failsafe mode enabled, in which case your boiler will cycle at 20%) it seems a no brainer that an automatic screen saver should at the very least activate when running on battery power to keep the unit functioning as long as possible.

One for the wishlist perhaps ?

This is one reason I have ours permanently mounted on a wall mount in the hallway and not in the living room - the screen glowing in the dark would be too distracting when trying to watch a movie.

[FullBore]

Please excuse very simple questions...

What is failsafe mode?

How does one enable it, and is it best practice so to do?

What is meant by the boiler cycling at 20%.

FB

[DBMandrake]

Failsafe mode is a setting in the installer menu. It's a little bit vaguely documented but basically if the BDR91 boiler relay looses wireless contact with the evotouch controller for an extended period of time, instead of staying off it will start firing the boiler at a 20% duty cycle, even if the heating was previously off. EG, 2 minutes on, 8 minutes off.

The idea is that if your evotouch controller died (or was left off the charger for 5+ hours) in the middle of winter it would cycle your boiler on for long enough to allow individual HR92's to continue to frost protect your house. Otherwise the individual HR92's would open their valves at 5 degrees but would be unable to call for heat from the boiler.

I enable failsafe mode in the winter when there is the risk of freezing, especially if I'm away from home. But the rest of the year I turn it off, as any wireless communication faults can cause the boiler to run unexpectedly, wasting gas. (And I have had this happen to me before)

What's not clear from the sparse documentation for this setting, is whether it also protects against the evotouch loosing wireless contact with an individual HR92 - EG does the boiler relay start firing at a 20% duty cycle if an HR92 lost contact. I've asked this a couple of times on the forum but the Honeywell guys have not yet clarified on this point.

Another point that needs clarification is that if you use an external wall sensor like a DTS92, the temperature reading from this is relayed via the evotouch to the HR92(s) for the zone - without the evotouch the HR92's would not know the temperature of the room and thus not know that they needed to open due to the room dropping to 5 degrees.

I don't know for sure but I believe if HR92's in external sensor mode do not get a temperature update from the evotouch for an extended period of time (30-60 minutes ?) they automatically fall back to using their internal temperature sensor, and thus would still be able to frost protect, but it would be nice to have this officially confirmed as well.

So basically failsafe mode is there to make the frost protection more robust if devices fail or lose wireless communication with each other, but with the risk that your boiler might fire unnecessarily if you do actually have a faulty/dead device or wireless communication issues.

[FullBore]

Many thanks DBMandrake

That's most helpful.

The next obvious question, to which I think I know the answer.

Presumably the 20% duty cycle is fixed, and one can't opt for say 40% or 50%?

[DBMandrake]

Yes it's fixed. It's only there for frost protection, and to protect the house against freezing in the owners absence.

If you were actually in the house needing normal temperatures and had an Evotouch controller fail completely you could still get heating by either pressing the button on the BDR91 to turn the boiler on, (this normally only turns it on for a short time but I think if it has no communication with the Evotouch it will stay on permanently after being manually activated) or using the constant switch on your boiler.

Then you can adjust the individual HR92's manually to control different rooms. (no schedule of course) HR92's can work autonomously - I actually had a single unbound HR92 in one room for months before I even had an Evotouch controller so I know this from first hand experience.