An Alternative Perspective

[DBMandrake]

I am from the camp that actually does not think the battery contacts are to blame. I actually think we feel they need fixing and in doing so reboot devices and hence they appear to work again. I actually believe the weakness is in the radio protocol.

I have to offer a contrary opinion on this - the battery contacts are definitely iffy on the Honeywell devices. Nobody has said they're the cause of all problems of course...

I've had nearly all of my nine HR92's and three of my five DTS92E's spontaneously shut off or reboot due to battery contact issues at one time or another. Just a couple of weeks ago I went to press the temperature adjustment button on a DTS92 and the whole thing shut off and then rebooted when I released the button. A light tap to the front cover once again caused it to go blank and reboot again. That's not my imagination Tighten up the contacts and reinsert the batteries and I was unable to reproduce the problem.

In the case of HR92's the issue is usually that it spontaneously reboots when the motor tries to adjust the valve pin, (especially when it reaches the limit stop) or sometimes with a relatively light touch on the top wheel it will reboot. Tightening the contacts fixes this too.

Poor quality "spring" steel in the contacts is the root cause of the problem I believe - it's soft and loses its tension over time.

[mtmcgavock]

I have to offer a contrary opinion on this - the battery contacts are definitely iffy on the Honeywell devices. Nobody has said they're the cause of all problems of course...

I've had nearly all of my nine HR92's and three of my five DTS92E's spontaneously shut off or reboot due to battery contact issues at one time or another. Just a couple of weeks ago I went to press the temperature adjustment button on a DTS92 and the whole thing shut off and then rebooted when I released the button. A light tap to the front cover once again caused it to go blank and reboot again. That's not my imagination Tighten up the contacts and reinsert the batteries and I was unable to reproduce the problem.

In the case of HR92's the issue is usually that it spontaneously reboots when the motor tries to adjust the valve pin, (especially when it reaches the limit stop) or sometimes with a relatively light touch on the top wheel it will reboot. Tightening the contacts fixes this too.

Poor quality "spring" steel in the contacts is the root cause of the problem I believe - it's soft and loses its tension over time.

Honeywell definitely have issues with their battery contacts - the new std programmable stats we fit are doing the same (And they're a new model out) End user picks the thing up to alter temp and the thing reboots! Having to tension them up from new.

I only yesterday had to tension up my T87RF as when altering it the thing reboots.

[DBMandrake]

On point 2, I think this would be useful for things like spare bedrooms or other unused rooms, which you want to be usually off but at a quick touch allow it to follow a 'normal' schedule if for example it is occupied by guests etc.

Just set a continous override to something like 10C in the guest room zone. It will be overridden by the heating off action but will go back to the continous override temperature when the system is turned back on.

To expand on that, the whole issue of zoning I find interesting. I'm not sure I ever found a definitive definition of what a 'zone' actually is in the context of the Evohome system, but made the assumption that it was a single or group of heating areas that can have their time schedule and temperature set, independent of other 'zones' (I think I was correct).

Yes, a zone is something that can be uniquely scheduled and controlled. Usually a single room, but there is a special "multi-room zone" zone type that can be configured which applies the same schedule to multiple rooms.

When I first mapped out my rooms and number of radiators it seemed to me that 12 zones was quite restrictive, on the basis that I'd like every room to be it's own zone. I have more than 12 rooms and I'm sure a lot of larger houses will too.
So I presume the idea of this is to group similarly used rooms together, but without making it so complex that there are too many schedules to keep programmed and up to date.

Some of these mappings are logical such as downstairs hallway and upstairs landing can be zoned together, and rooms connected via an opening such as kitchen/dining room in my case, which in effect is one large room.
However once you do this and set up the zoning, it seems you lose any visibility of the rooms within a zone. For example, in 'System Summary' all I see is RADIATOR VALVE. It doesn't tell me that 'Living room' actually has 2 radiator valves in the same room, or that 'Kitchen Dining' is actually 2 rooms with a radiator valve in each.
I would have liked to see the setup process involving adding each room by name as step one, then grouping these into zones, with the ability to move them between zones (e.g. moving a Guest Bedroom from an 'unused' zone to an 'active' zone)
I'm interested in how everyone else manages the zoning process?

A key thing to think about when you consider different combinations of radiators and rooms for zoning is whether to use a single room zone or a multi-room zone. (This is a setting within the zone settings)

In a "single room zone" there is only one nominated temperature sensor for the zone and all TRV's within the zone use this reading. This sensor could be a wall sensor or one of the HR92's in the zone. (You can choose which one) Multiple HR92's in a single room zone work in unison when controlling their radiators as they are supplied the same set point and the same temperature measurement to work from. (Relayed via the controller)

Single room zone is the obvious choice if all the radiators in the zone are in the same "space", such as a closed off room. It gets a bit more nebulous in an open plan area like a joined kitchen / dining room area whether single room zone (and thus a single sensor) is appropriate because if the thermal characteristics of the two areas are too different you might see quite a heat gradient across the area. (Like heat from a kitchen causing that to be hotter than the dining room side, and radiators not compensating)

A multi-room zone still tells each HR92 to follow the same set point schedule but to use its own internal temperature sensor. The primary use for this mode is if you want to combine different rooms into the same zone for the purposes of scheduling and reducing the number zones required. A good example would be combining two children's bedrooms - you want the same temperature schedule in both rooms but measuring the temperature in one room is obviously not going to regulate the temperature in the other room properly - they must both use their own individual sensors.

However it can also be used in scenarios like upstairs/downstairs landing (the upstairs will generally be hotter if only one sensing point is used) large open plan areas with different thermal characteristics around the "room", unusually long and skinny living rooms etc...

The pros and cons of the two modes are:

Single room zone - one nominated sensor takes the reading for the entire zone and all TRV's operate in unison using the same inputs to control the radiators equally. A remote wall sensor can be used for better accuracy. Adjusting an HR92 directly will show the manual override on the controller and also change the set point of the other HR92's in the zone. (After a few minute delay) Not appropriate for radiators in completely different rooms or spaces.

Multi room zone - every HR92 uses its own internal sensor to make a decision about its own radiator heat output to regulate the temperature in it's vicinity. A remote wall sensor cannot be used. Adjusting an HR92 directly will change the set point on that HR92 (until the next scheduled set point change) but this change will NOT be shown on the controller and will not propogate to other HR92's in the same zone. (So one child adjusting their bedroom HR92 won't affect the other bedroom in the same zone) Appropritate for radiators in different rooms/spaces, and might also be useful in large areas that are nominally a single space but are too disjoint in thermal properties to get an even heat throughout the area from a single temperature measurement. Only the temperature measurement of the first HR92 is displayed on the controller so there's no way to know from the controller what temperature is measured at additional HR92's in the zone - you need to look directly at the HR92.

Other than that so far so good. A couple of minor things, such as the controller doesn't sit very tightly or securely on the wall-mount kit - it wobbles a bit when you touch the screen, and it can be lifted straight off. I would have liked to see it lock into place, as I have visions of it getting knocked upwards then falling straight onto the floor off the mount.

Yes this looseness on the wall-mount is worrying to me too, on a couple of occasions it has been knocked in an upwards direction and nearly come off the stand. It's a snug fit on the table stand so its disapointing that the wall mount is so loose. When I get around to it one day I plan to apply some thin self adhesive felt pad to the wall mount around the centre connector to pad it out a bit and make it a bit tighter.

Also I have the HR92 set for 'room temperature' display which to me seems preferable to set temperature. However as the bottom part of the LCD is unused in idle mode, it would have been nice to have the 'other' temperature displayed at the bottom too. Don't know whether these devices are capable of receiving OTA firmware updates from the controller?

As far as we know field / over the air firmware upgrades for the HR92 (and all devices apart from the Evotouch controller itself) are not possible unfortunately. Also the HR92's LCD screen is not a bitmap screen - it's a fixed symbol screen like an LCD watch with the lower line designed for letters - there's no guarentee that it has the necessary symbol segments to be able to display a temperature at the bottom. (But even if it could, the lack of any firmware updates is a show stopper - there have been no HR92 firmware revisions for the last 5 years)

[G4RHL]

Like you the HW is the only sensor that reports regular loss of comms. This is not a battery issue because it has be occurring on and off since the system was installed. I think the problem is that it is impracticable to mount it away from the HW tank and pipework. I would prefer it to be mains powered and have a more robust radio signal/protocol.

The issue with batter contacts is seen when batteries are replaced or the valve head moved. Just a gental tap can cause the display to blank and the device reboot.

My HW sensor is about the same distance away from the HW tank and pipework as the CH heating relay but that never has the same problem. My CH relay is just marginally further away. No problem. However, the CH sensor, whilst the same distance from the tank as the CH relay, is lower down with the full body of the tank in front of it. The CH relay is higher up and “sees” more of the top of the tank as it comes to a curved top. I expect some attenuation, but it is not all the time. As dpmandrake found it could well be the orientation of the antenna in the sensor.

It could of course be that the sun spot cycle is not good and won’t be for some years to come and thus affecting many radio signals!

[filbert]

I am from the camp that actually does not think the battery contacts are to blame. I actually think we feel they need fixing and in doing so reboot devices and hence they appear to work again. I actually believe the weakness is in the radio protocol.

In the couple of years I’ve had Evohome (with 12 HR92 + HW) I’ve not noticed any problems with battery contacts. I do find the little springs a pain to release and reset when putting new batteries in, though.

[benwillcox]

Just set a continous override to something like 10C in the guest room zone. It will be overridden by the heating off action but will go back to the continous override temperature when the system is turned back on.

Ah yes that does have the same desired effect, thank you.

Yes, a zone is something that can be uniquely scheduled and controlled. Usually a single room, but there is a special "multi-room zone" zone type that can be configured which applies the same schedule to multiple rooms.

Thanks for the detailed explanation, it makes sense for things like a downstairs hallway/upstairs landing to be a multi-room zone as the temperature differential between the two sensors will be quite high.
It almost seems like there should be another mode, like multi-room zone but that allows either HR92 to adjust the set temperature and mirror that to the other HR92s. Or to average the reading between multiple sensors in a single-room zone. In reality I doubt I'll be using the manual control on the HR92 anyway so doesn't really matter.

As far as we know field / over the air firmware upgrades for the HR92 (and all devices apart from the Evotouch controller itself) are not possible unfortunately. Also the HR92's LCD screen is not a bitmap screen - it's a fixed symbol screen like an LCD watch with the lower line designed for letters - there's no guarentee that it has the necessary symbol segments to be able to display a temperature at the bottom. (But even if it could, the lack of any firmware updates is a show stopper - there have been no HR92 firmware revisions for the last 5 years)

I did notice that I think there is a USB socket underneath a cap on the HR92 so maybe firmware updates aren't out of the question. The lower line on the display is a multicharacter 11 segment display so more than capable of displaying temperature, albeit without the 'degrees' symbol. Something like '20C' would be fine.

[bruce_miranda]

There is a USB socket on the previous generations of Evohome control panels too, but the firmware has never been officially updated on those either. The only devices that have actually received any firmware update has been the Internet Gateway and the WiFi controller.
So I would say the chances of seeing a firmware update on anything else is the square root of 0.

[DBMandrake]

e is a USB socket underneath a cap on the HR92 so maybe firmware updates aren't out of the question. The lower line on the display is a multicharacter 11 segment display so more than capable of displaying temperature, albeit without the 'degrees' symbol. Something like '20C' would be fine.

It's not a USB socket, it's a connector for connecting a physical "window open" switch.

This allows the window open function to be activated by something like a reed switch when a window is physically opened instead of relying on temperature drop heuristics to detect a window (or door) left open. It's documented in the HR92 installation manual and is enabled through one of the window settings in the HR92 settings menu.

I don't know of anyone who is using this feature though or whether the companion sensor is readily available! (Although as it's just a switch you could make your own if you have the right connector - I think it might actually be a micro-USB connector but it is definitely not USB signalling)

[CT1]

I have been going through the irritating process of trying to get the batteries in the controller to accept a full charge. Something that I do not think the user should be expected to do. As part of this and to check it has worked, I have had the controller off the wall for some time and have taken the opertunity to see if the location has any affect on the loss of comms with the HW sensor. I have been unable to force a loss of comms, no matter where I place the controller in relation to the tank and pipework. It does not therefore look as though this is the cause of my occasional loss of comms. Maybe the sun spot hypothesis needs further investigation.

[benwillcox]

It's not a USB socket, it's a connector for connecting a physical "window open" switch.

Ah yes I do recall seeing that in the manual now you mention it. Ah well, I'll forget any idea of future firmware updates then!

Nobody else finding that the maximum of 12 zones is limiting, if wanting to go for a one zone per room approach?