Replacement for fFaulty Wireless Honeywell Room Thermostat, DT92E

dogfonos

The Wireless Honeywell Room Thermostat, DT92E fitted as part of the Honeywell boiler/hot water controller/programmer has an intermittent fault whereby it occasionally changes the temperature setpoint all by itself! I'm all for taking the initiative but this has gone too far. I need a replacement wireless room thermostst - doesn't need to be programmable - and I'm reluctant to replace like with like as the Wireless Honeywell Room Thermostat, DT92E has been unreliable and a brief Google reveals many other dissatisfied customers.

BUFF

You will need to replace with something that can bind to/use the Honeywell Wireless Relay Module (so most likely another Honeywell unit) or replace both items.
I would recommend having something programmable & with modern electronics they start from very cheap.

ThisIsWeird

Looks like the receiver is not on a standard backplate, so that means you'll need to undo some wired - probably three - unscrew the existing plate, refit the new one (very likely will be 'standard', so will accept a range of receivers), and refit the wires. This isn't any more physically complex than wiring a plug, but you will need to know what the wires do - and be able to isolate the power to it, 100% guaranteed...

So, are you up for that? If so, we can guide you. That leaves the Q - which replacement?!

Lots of options. I'd STRONGLY recommend a Programmable type, since these almost certainly will save you energy. I'd STRONGLY suggest 'Smart' with App control, too, for ditto and sheer ease of use. The biggest problem with Prog Stats is setting up schedules - and then changing them when required. App control will do this both intuitively, and in seconds. Lots of other pluses too. Since there's little to chose between then in cost, I think you'd be daft not to.

Most recommended on here is 'Wiser'. There's also Nest and Hive and plenty others. 

So, the only way I know of for a 'straight' replacement - Ie keeping the current wireless receiver and just replacing the stat - is to go for another DT92e, unless they make other models that use the same receiver. What do you think?!

ThisIsWeird

Seemingly the BDR91a receiver will work with all Honeywell stats that use their 'Remeses 2 protocol', whatever the heck that is.

[Deleted User]

From the Resideo (Honeywell) website:

‘The DT92E thermostat can be replaced with the Y87RF Single Zone Thermostat together with the RFG100 Remote Access Gateway, or the evohome controller. Both devices can be controlled by your phone and will connect to the existing BDR91 relay box.

The Lyric T6/T6R Smart Thermostat can also be a suitable replacement for the DT92E, but the relay box needs to be replaced.’

Have you by any chance had a fiddle with the thermostat? I ask because it is very easy to double bind a device to a BDR91. I spent a whole day resetting a Evohome system after a so called Honeywell Connected specialist managed to double bind three components. The online connected specialist course takes about 2 hours to complete! 

dogfonos

Thanks for your responses, much appreciated.

Can we take a step back please? There's stuff mentioned here that I don't understand. I don't have the Honeywell BDR91 relay box that I note is often sold with the DT92E. I assume this extends the 30m wireless transmission range of the DT92E? Whatever, it's not in my setup, which is: DT92E room thermostat, ST9420C wireless programmer and CS92A wireless cylinder thermostat.

I appreciate suggestions of buying a programmable room thermostat but for the life of me, I can't see any benefit to the way I use a room thermostat. Maybe I'm missing something as you're not the first folk to suggest a programmable room therm. I've read up on them before, understood their purpose but couldn't see any advantage (for me), but will re-investigate. And yes, I agree
they don't cost much more than a standard RT.

Dolor said:

From the Resideo (Honeywell) website:

‘The DT92E thermostat can be replaced with the Y87RF Single Zone Thermostat together with the RFG100 Remote Access Gateway, or the evohome controller. Both devices can be controlled by your phone and will connect to the existing BDR91 relay box.

The Lyric T6/T6R Smart Thermostat can also be a suitable replacement for the DT92E, but the relay box needs to be replaced.’

Thanks for the info. I hadn't spotted that when I checked out the Resideo website but I have asked a question via their webform and await a response.

Dolor said:

From the Resideo (Honeywell) website:

Have you by any chance had a fiddle with the thermostat? I ask because it is very easy to double bind a device to a BDR91. I spent a whole day resetting a Evohome system after a so called Honeywell Connected specialist managed to double bind three components. The online connected specialist course takes about 2 hours to complete! 

Your experience (together with others' anecdotal accounts) demonstrates why I would have preferred a far simpler setup, just like the setup we had prior to extensive building work carried out about 5 years ago (concentrating on the big decisions meant I overlooked a few minor details). The old, simple wired setup never missed a beat in over 20 years. Reliability is paramount for me. I'm only into tech. gadgetry when it benefits me in practical ways. And I'm one of approx 15% of UK adults who don't own a smartphone - the cost-to-benefit ratio isn't currently favourable for me - so any "app" based solutions are not an option, I'm afraid.

ThisIsWeird said:

So, the only way I know of for a 'straight' replacement - Ie keeping the current wireless receiver and just replacing the stat - is to go for another DT92e, unless they make other models that use the same receiver. What do you think?!

I think you're correct. I checked out other big brand (Danfoss) wireless room thermostats but they operate at different frequencies and probably have different wireless communication protocols too. It will be a nightmare (and yet more wasted time) attempting to mix & match other brands. Couldn't help noticing that a Danfoss programmable wireless RT typically costs about one third the price of a new DT92E. Doesn't enamour me to Honeywell products but it seems I have little choice. Were it not for the significant disruption that would be caused (not to mention cost), I would revert back to old tech. wired room and hot water cylinder thermostats with a wired controller/programmer - assuming they're still available?

Reluctantly, I'll have to go with another DT92E. Thanks again for your inputs.

[Deleted User]

dogfonos said:

Thanks for your responses, much appreciated.

Can we take a step back please? There's stuff mentioned here that I don't understand. I don't have the Honeywell BDR91 relay box that I note is often sold with the DT92E. I assume this extends the 30m wireless transmission range of the DT92E? Whatever, it's not in my setup, which is: DT92E room thermostat, ST9420C wireless programmer and CS92A wireless cylinder thermostat.

I appreciate suggestions of buying a programmable room thermostat but for the life of me, I can't see any benefit to the way I use a room thermostat. Maybe I'm missing something as you're not the first folk to suggest a programmable room therm. I've read up on them before, understood their purpose but couldn't see any advantage (for me), but will re-investigate. And yes, I agree
they don't cost much more than a standard RT.

Dolor said:

From the Resideo (Honeywell) website:

‘The DT92E thermostat can be replaced with the Y87RF Single Zone Thermostat together with the RFG100 Remote Access Gateway, or the evohome controller. Both devices can be controlled by your phone and will connect to the existing BDR91 relay box.

The Lyric T6/T6R Smart Thermostat can also be a suitable replacement for the DT92E, but the relay box needs to be replaced.’

Thanks for the info. I hadn't spotted that when I checked out the Resideo website but I have asked a question via their webform and await a response.

Dolor said:

From the Resideo (Honeywell) website:

Have you by any chance had a fiddle with the thermostat? I ask because it is very easy to double bind a device to a BDR91. I spent a whole day resetting a Evohome system after a so called Honeywell Connected specialist managed to double bind three components. The online connected specialist course takes about 2 hours to complete! 

Your experience (together with others' anecdotal accounts) demonstrates why I would have preferred a far simpler setup, just like the setup we had prior to extensive building work carried out about 5 years ago (concentrating on the big decisions meant I overlooked a few minor details). The old, simple wired setup never missed a beat in over 20 years. Reliability is paramount for me. I'm only into tech. gadgetry when it benefits me in practical ways. And I'm one of approx 15% of UK adults who don't own a smartphone - the cost-to-benefit ratio isn't currently favourable for me - so any "app" based solutions are not an option, I'm afraid.

ThisIsWeird said:

So, the only way I know of for a 'straight' replacement - Ie keeping the current wireless receiver and just replacing the stat - is to go for another DT92e, unless they make other models that use the same receiver. What do you think?!

I think you're correct. I checked out other big brand (Danfoss) wireless room thermostats but they operate at different frequencies and probably have different wireless communication protocols too. It will be a nightmare (and yet more wasted time) attempting to mix & match other brands. Couldn't help noticing that a Danfoss programmable wireless RT typically costs about one third the price of a new DT92E. Doesn't enamour me to Honeywell products but it seems I have little choice. Were it not for the significant disruption that would be caused (not to mention cost), I would revert back to old tech. wired room and hot water cylinder thermostats with a wired controller/programmer - assuming they're still available?

Reluctantly, I'll have to go with another DT92E. Thanks again for your inputs.

Honeywell offers some very high quality products. I had Evohome in my previous home which connected to 2 boiler demand relays (BDRs). The BDR is a just a wireless operated device that turns power on and off. 

The DT92E must be ‘bound’ (connected) to something.’ The connection can occasionally be lost and all that is needed is re-binding BUT you have to be careful to remove any old settings first.

If you would like some specific Honeywell - centric advice then I would  post on this forum:

https://www.automatedhome.co.uk/vbulletin/forumdisplay.php?13-Heating-Control

ThisIsWeird

dogfonos said:

Thanks for your responses, much appreciated.

Can we take a step back please? There's stuff mentioned here that I don't understand. I don't have the Honeywell BDR91 relay box that I note is often sold with the DT92E. I assume this extends the 30m wireless transmission range of the DT92E? Whatever, it's not in my setup, which is: DT92E room thermostat, ST9420C wireless programmer and CS92A wireless cylinder thermostat.

Ah, my apologies. So the ST9420C appears to be a wireless 'receiver' too, so communicates directly with the DT92E room stat, and also the CS92A cylinder stat. As you say, no BDR91 required.

Nice system, and I suspect not worth moving away from - unless Honeywell have some alternatives to the DT92E that will also work with the ST9420C? I'd drop them an email or 'chat'.

Why a Prog Stat? Well, how many times did you press the up and down buttons on the DT92E today - so far? A Proggie would have done most of these for you. And that's how it saves you energy - it never forgets to turn the stat down, and back up, and saves you the hassle. A Smart version with App control makes setting it up a breeze - sooo easy - and gives you instant override as well.

Forgot to turn the heating down when you went out t'pub? No problem - stab at your phone screen. And, if you are sober enough, stab it again before you stumble home.

Anyhoo, since you don't much like the DT92E, I'd take the opportunity to ask Honeywell what other room stats are directly compatible with the ST9420C, if any, and go from there.

dogfonos

ThisIsWeird said:

dogfonos said:

Thanks for your responses, much appreciated.

Can we take a step back please? There's stuff mentioned here that I don't understand. I don't have the Honeywell BDR91 relay box that I note is often sold with the DT92E. I assume this extends the 30m wireless transmission range of the DT92E? Whatever, it's not in my setup, which is: DT92E room thermostat, ST9420C wireless programmer and CS92A wireless cylinder thermostat.

Ah, my apologies. So the ST9420C appears to be a wireless 'receiver' too, so communicates directly with the DT92E room stat, and also the CS92A cylinder stat. As you say, no BDR91 required.

I'm the one who should apologise. I intended to add this info. to my original post but somehow pressed the wrong button and accidentally posted before I was ready. And I couldn't see a way of then editing my post. Ah well...

Yes, it's not a bad setup - when it's working. I've since read more about placement of the DT92E and it was sitting too close to a wired landline 'phone (incl. wired handset) so I've moved it the Honeywell recommended distance of 1m away.

ThisIsWeird said:

Why a Prog Stat? Well, how many times did you press the up and down buttons on the DT92E today - so far? A Proggie would have done most of these for you. And that's how it saves you energy - it never forgets to turn the stat down, and back up, and saves you the hassle.

Because of the DT92E tendency to change it's own temp setpoint, I'm checking setpoint once or twice a day. Other than that, I genuinely haven't touched the thing for months. Last time was probably to reduce the setpoint temp when I received a gas bill in June!

My household is rarely fully unoccupied and even so, I can't predict those occasions when it is likely to be so, therefore I couldn't program times/temperatures into the prog room thermostat in advance. I do see the usefulness if a household is regularly, or at least predictably, unoccupied for a time but for me, it's easier to just switch heating off on the ST9420C when we leave and back on when we return. If the place is going to be unoccupied for a long period, I'd turn heating and hot water off on the ST9420C and leave it on frost protect. True, the home could be pretty cold when we return after an extended absence but that's only a minor, and rare, inconvenience.

[Deleted User] said:

Honeywell offers some very high quality products. I had Evohome in my previous home which connected to 2 boiler demand relays (BDRs). The BDR is a just a wireless operated device that turns power on and off. 

The DT92E must be ‘bound’ (connected) to something.’ The connection can occasionally be lost and all that is needed is re-binding BUT you have to be careful to remove any old settings first.

If you would like some specific Honeywell - centric advice then I would  post on this forum:

https://www.automatedhome.co.uk/vbulletin/forumdisplay.php?13-Heating-Control

Fair enough. You mention some alternative products (to the DT92E) in your first post so I'll check these out and contact Honeywell/Resideo. Thanks for the Honeywell forum link. Have to say neither the DT92E or CS92A have ever lost connection with the ST9420C. I've changed batteries in both the DT92E and CS92A once in 5 years of use and don't even remember 're-binding' so it must have happened automatically or was a very simple process.

Thanks again folk. Your help has been much appreciated. Happy New Year!

ThisIsWeird

And to you and yours.

hitman

I know this is an old thread, but I came across this when investigating a similar problem to the OP.
In my situation I noticed my DTS92E would occasionally show a blank screen when moved and perhaps at other times. Batteries were fine.

I figured this intermittent power loss could be causing a reset, and on some days no heating if the thermostat was offline!

I decided to open up the thermostat to see if there were loose connections. There are spring based metal contacts from battery holder to circuit board. I tensioned these up slightly by just bending the contacts up a bit, and also cleaned the contact points on the circuit board with an eraser.

Putting it all back together seems to show this has helped as shaking the thermostat no longer results in a blank screen.

To open the thermostat there are two lugs behind the batteries. The circuit board can be removed by prising up gently from the bottom end.

Hope this helps someone else in future.