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EvoHome, a mini review

PostPosted: Sat Jan 31, 2015 12:33 pm
by MindBender
After many long abandoned plans of controlling our Remeha boiler through the Remeha Gateway and set of Honeywell HR80 valves wirelessly, I finally realised it was time to act. Because what I wanted when I joined the forum a long time ago - controlling my heating system from my phone - seems nowadays standard on more advanced thermostats, such as NEST, Toon, etc. Briefly I considered getting NEST, but it not being an OpenTherm controller, and Google being the puppet master behind the curtain, I quickly started looking for alternatives. A pity, because I really like the NESTs design.

My choice fell on Honeywell's EvoHome system. The colour touch controller isn't as pretty as NEST, but it does support OpenTherm, modulating (proportionally controlled) boilers, it is able to control different zones separately, using wireless HR80 or the more modern looking HR92 valve controllers. And to top it off, there's even a Honeywell Gateway connecting it to the internet. Everything I ever wanted, for just €1200.

Installing the system was a breeze. Although there is an annoying snag in the touch controller software: When adding valve controllers, it regularly says it has added one (or two) more than you actually added. Perhaps it recognises duplicates, and the snag is only in the reported number, but I do get communication errors reported in that zone. And there is no way to list the controllers associated with a zone and remove separate controllers. All you can do is remove the whole zone and add it again, hoping no duplicates show up. I gave up after 8 retries with all different valve controllers.

The touch controller shows the actual temperature and setpoint for all zones, up to 6 in the first screen, up to 12 in total. Unfortunately it doesn't show the outside temperature, even though the documentation says this information is read from the boiler and actually used in the control algorithm (if the boiler is equipped with an outside temperature sensor, like mine). I think this is a missed chance.

The touch controller can be removed from it's stand, but I really don't see the point of doing that. It's more convenient for programming, but the device quickly heats up in your hands, indicating a room temperature for well over 30 degrees after just a couple of minutes. Perhaps Honeywell should ignore this sensor when the touch controller is running on batteries. When running on batteries, the touch controller beeps shortly every 30 minutes or so. It took me a long time to figure out where the beeping came from, and why it was doing that.

Zone temperatures can be controlled independently. The system can measure the zone temperature using the valve controller's sensor, or the touch controller's internal sensor. The latter only for the zone it it located in, of course. For every zone, a time schedule can be set. Schedules can be copied, day to day, and zone to zone. Zones can be combined, like kitchen and living room. For each zone, adaptive heating (optimisation) can be enabled, making the system anticipate on changing setpoints: It will start heating earlier, to make sure the zone is at the specified temperature at the specified time, instead of starting to heat at the specified time. It can also do the same for cooling down situation, preventing the system to start heating 5 minutes before the heating is supposed to turn off at the end of the evening. The optimisation feature is per default enabled for all zones, but confusingly system-wide disabled.

Zone setpoints can be easily changed, on the touch controller, on your phone if you have a gateway, and on the valve controller dial. This latter function however, seems to have a bug: The new setpoint isn't indicated on the touch controller. Neither are other valve controllers in the same zone updated with the new setpoint. It may be a feature, but a dumb one at that. When changing setpoints on the touch controller, it also asks until what time you want this manual override over the program to be active, with an option to make it permanent. I find this function extremely useful, because it prevent forgotten manual overrides going on for weeks. On a regular system, a forgotten opened radiator knob doesn't have a much impact as on this system: With this system, an opened radiator knob actually turns on your boiler.

My setup consists of the following components:
1 Touch controller (colour), with the 3 optional fronts (of which one is white, like the standard one already installed, rather silly)
1 Wireless OpenTherm interface
1 Internet Gateway
10 Valve controllers, for 8 difference zones

Now I can only hope this system is efficient. I bought it mostly for comfort reasons, but I don't want my gas bill to double. This is another reason why I chose Honeywell: They're not doing OpenTherm, modulating boilers and wireless radiator controllers for the first time. Many of the alternatives only do at most 2 out of these 3, and they all do it for the first time. And it's not hard to make a thermostat that works, but it is hard to make one that works well.

I hope this information is useful to anyone. I was unable to find many of the things I wrote down here in the documentation. For anybody interested in this system, I recommend reading my next post 'EvoHome, OpenTherm and Remeha' (viewtopic.php?f=70&t=10280) as well.

Re: EvoHome, a mini review

PostPosted: Mon Feb 02, 2015 11:54 am
by MindBender
This is a serious bug/shortcoming/feature:
Last night I woke up in the middle of the night and I heart the boiler burning. Considering the problems we are experiencing, I stepped out of bed to check if it was stuck in an error again. It was not: According to it's status display I was heating water up to 100 degrees for heating. Heating for warm water I could still understand, because it has a small reservoir to keep warm, but for heating is strange. So I went downstairs to check the EvoHome touch controller. All setpoints were well below the actual temperatures, so the was no reason for the boiler to burn.

However, I noticed the temperature in my office to be 22 degrees. And I remember dialling the radiator controller to that temperature earlier that day. So I went to my office and checked: It was a pleasant 22 degrees there and the radiator controller still reported a setpoint of 22 degrees, even though I had remotely set a lower temperature for that room on the touch controller at the end of the day.

I already posted that a setpoint set from the radiator controller dial isn't communicated back to the touch controller. But what is much worse is that such a manual setpoint cannot be reset from the touch controller! So these local setpoints will be active until deactivated locally. Which could be a very long time if activated accidentally, by kids or by a cat stepping on the dial. And again: The consequence of this is much worse than a parasiting radiator in a regular system. In an EvoHome system it will actually turn on the boiler, 24/7/365 if necessary, potentially wasting a lot of energy.

Re: EvoHome, a mini review

PostPosted: Mon Feb 02, 2015 5:33 pm
by Akatar
strange bug, because the radiator valve is communicating with the thermostat.