Honeywell Evohome Controller Reset Itself

[G4RHL]

Thanks for this. Good to know that all I have to do is wait. Yes, it is the desktop unit I have and I had just been unplugging it as it was easier. This time I had taken it from it's cradle and when I had gone to put it back on, I think that what I had done was just touch the contacts together briefly which caused it to reboot. (I was able to replicate it).

Yes, I am a complete newb to Evohome and to home automation although I am getting sucked in (today there is an electrician as I type installing LightwaveRF switches at home). At a user level I like to think of myself as a bit of a techie but what is frustrating is that there is not much around to read up on, such as FAQs, troubleshooting, how people have got round various issues.

I have the newer HR92s and I think that they just reconnect themselves after a comms fault (what causes these?) but again, good to know that taking a battery out could make it sync.

When I first looked into the Evohome I thought that the rad valves were removable so that they could pick up the temp in a different part of the room but they are obviously not.

Also something else that would have been good would be a wireless window sensor as someone always leaves our kitchen door open in our house - if there was a way of incorporating the window sensor that Lightwaverf does into the Evohome......

You will find LightwaveRF gear very useful. I started to go that route 2 years ago and also change light bulbs to LED ones. All lights, including garage and outside ones are controlled using LightwaveRF and I have installed some sockets as well. I have used a number of plug ins as opposed to installing sockets simply because it is easy. It does give good control from wherever you - Australia for me a couple of months ago.

For heating though I went the Evohome route. Costs me more but the quality is excellent. There is though often a delay in things happening, when resetting etc. Once you know it happens then the concern goes! Possibly it is due to the inbuilt delay with the TRVs communicating back and forth as they do so at about 4 minute intervals I believe.

I set the optimisation parameters recently and to my surprise the system seems to learn and adjust. At first heating came on about an hour ahead to warm a room to its set temperature as set by the timer but I noticed after a few days this began to change, it is not always an hour and often less and seems to be dependent on the actual temperature of the room at the time it calculating the time it may take to get up to temperature so that how soon it switches on depends on the actual room temperature at the time. Also, and am not sure if I am right on this, but it also seems to learn how long it takes to warm a room up as well. It could be just me but it seems that way.

The system works well. Am running with 11 zones (every room is set as a zone) and 12 radiators with the TRVs. There is a 13th radiator without one to provide a relief go the pump if all others close down and the pump is on an overrun. This one is the downstairs loo. Its lovely and warm in there!! I have noticed since installing it all though that the boiler/pump rarely goes into overrun when the heating goes off. It always used to happen before. Not now it seems.

[SensibleHeatUK]

Regarding optimisation (you can set Optimum Start and Optimum Off if preferred) then yes, the units do learn the characteristics of the room and adjust this automatically depending on the room temperature and setpoint target. The units also measure the accurracy of room temperature control and automatcially adjust their valve modulation to improve control accurracy. These features have been in the previous generation of the control for many years and come from strategies used in commercial buildings with full scale BMS systems. In fact the modules here do a far better job than most BMS systems as the programs have been developed and tested over many years and a lot of effort has gone into the fuzzy logic self-learning/tuning algorithms to ensure they are effective. Many BMS systems are still programmed during commissioning using code written by the commissioning engineer, and very often use generic PID control loops that are never properly tested/tuned/adjusted leading to poor levels of control that are never improved. Honeywell's approach guarantees that the majority of installations are optimised without user intervention and deliver the best performance possible within the boundries of the user settings and the limitations of the mechanical systems they control.

[G4RHL]

Thanks for confirming my suppositions! It certainly has seemed to gradually adjust in the optimisation setting. A definite learning process. Such that I have now moved my start times for some zones forward by an hour letting the optimisation do its thing.

Initially I also spent some days monitoring the temperature in rooms at say waist height using two thermometers for reference purposes. This showed the reading in the TRVs in some cases was lower than actual room temperature, in one case it was higher. Possibly the lower temperature may be due to drafts at ground floor level plus the fact that hot air rises so it will be warmer higher up. I adjusted the relevant TRVs to compensate but still ended up with different readings. Assuming that possibly there is no real need to make these adjustments I have reverted back to a zero compensation setting and accept the room temperature will be higher. Indeed at night with curtains closed in my lounge the TRVs are set to 21C but the room temperature at waist height is often 23 or 23.5C. Perhaps I ought to try adjusting again?!

For those also installing hot water with Evohome what is not clear in the manual and took some solving was the need to pair the sensor on the tank to its receiver first, then pair to the hot water relay, then pair to the heating relay and in that order.

It would be more useful if the custom menu/override could be more editable and also if there was the facility to add additional custom menus or perhaps make all the others customisable which probably could be simply done with a software upgrade. For example the preset menu that reduces all to 15C if one is away is fine but it is all, I have a radiator in my conservatory which if set to 15 will come on. It would be nice if I could edit that menu so that the conservatory is isolated to come on if say the temperature dropped to 3C - indeed not 5C! With the minimum set at 5c I hear the heating operating during the night but it would not at 3C as the temperature rarely if ever drops that low. I have used the custom menu to get around this but it still leaves the conservatory set to a minimum of 5C and that I think is too high.

A great system though. I have ended up with a much more balanced heat throughout the house.

[SensibleHeatUK]

When you bare in mind that water can start to freeze at temperatures just above freezing (upto 4 degrees in certain circumstances) I would guess that the 5 degree minimum was chosen deliberately for this reason. Evo is sold all over Europe, with external temperatures that will be far colder than that in the UK, so I expect it will be a safe temperature for those areas too. I've certainly had customers who have suffered frozen/burst pipes and now have a requirement by their insurance company to maintain 7 degrees as the minimum internal temperature otherwise they will not be covered against future frozen pipe claims.

Due to the way the HR92s operate they may start to open the valve/run the heating before the minimum temperature is reached, so even at 3 degrees you may not stop the heating from firing up in the Conservatory when it gets very cold. It does this so as to make sure the room temperature does not fall below the minimum setting while it waits for the circuit to warm up and start heating the room.

I actually prefer the simplicity of the quick action/custom menus now that you can also override any zone directly too - the older Hometronic system had 16 customisable overrides (although none had any time program control) which were either rarely used, or became very complicated to manage as only one override could be active at a time.

[G4RHL]

Yes, a good point worth making - freezing can start at higher temperatures than you may think. Too many customisable menus would certainly create chaos but a little more flexibility with what we have would be helpful. Possibly there is also an IFTT patch that someone has written that does this. But then you can so easily make things over complicated.

Have had mixed messages from insurers when leaving my property unoccupied. From the minimum setting to be 5C, 7C, or 10C, having to do a complete drain down and the one that I think gets first prize is to drain the system but you do not need to drain the radiators! When I pointed out the stupidity of this to the insurers they came back to me and amended the condition to keeping the heating on set to no less than 10C.

One thought, it would be a nice touch to have a device that guests can have to turn up the radiator in their room without showing them how to take the end cap off and adjust it with the little wheel nor by letting them have the app on their phone. Or would the free standing thermostat do that if left in a guests room to use? I presume it will.

[SensibleHeatUK]

The dial on they top of the HR92 allows for simple guest adjustment (or the same could be achieved with a DT92 or new single zone thermostat on the wall), so no need to remove the HR92 to get at the inner gear or provide access via the app. And any adjustment is temporary as it will be reset by the next time program entry, so no risk of the setting remaining permanently changed.

[G4RHL]

There is no dial on my HR92s and to manually adjust I have to remove the end cap to expose the inner gear. I think the single zone thermostat may be the best option (Evohome Y87RF2024). Of course when we have guests I could always tell them its just tough if they don't like the temperature of their room! The spare bedroom is currently set at 15C!

[SensibleHeatUK]

All HR92s have the adjustment dial on the top (it is the circular cover that hides the ) - it is a standard part of the design! In the settings menu it can be disabled so turning it would have no effect on the setpoint. However under normal settings you can adjust the setpoint using the dial.

[G4RHL]

Think we are saying the same thing. To access the adjustment dial you have to, with your finger nail, prize off the circular cover. Indeed the same dial that is used to change the settings. Probably best not to tell guests about this in case they play around with other settings. The single portable room stat seems to be the best route for me telling them to turn the dial if they want it warmer or cooler but for God's sake to keep the stat in their room and not walk into another with it!

[The EVOHOME Shop]

Think we are saying the same thing. To access the adjustment dial you have to, with your finger nail, prize off the circular cover.

The white circular cover is the 'adjustment dial', no need to take it off...