Honeywell wireless room thermostat (DT92E) - weird problem

[dogfonos]

Would appreciate views on this strange problem I'm having with a Honeywell wireless room thermostat (DT92E) that was fitted to my central heating system five years ago.

Three or four times over the past five years the Honeywell DT92E appeared to change room temperature setpoint (increased by 1 or 2 degrees) without any human involvement. First couple of times I thought me or someone else must have accidentally touched the setpoint button (not so easy as it takes a few button pushes to change the setpoint a couple of degrees) - perhaps when the decive was picked up or moved (if indeed it had been).

Since then though, we've not touched the thing, yet it has still changed setpoint, without human input, two more times. Weird. Last time I corrected the setpoint, I pinned a sticky note on it with the setpoint and date. There's only two of us in the household and I'm certain neither of us or any visitors has touched the thermostat. And I don't think the place is haunted!

Question is: Is it unheard of for wireless room thermostats to change their own setpoint occasionally? Anyone have any experience of this particular device? Thanks.

 

[gas112]

poltergeist , very common fault

 

[dogfonos]

poltergeist , very common fault

Well, any malevolent spirits better watch out as the mother-in-law is due to visit over Christmas.

Thinking about it, the cat has been looking a bit shifty...

 

[dogfonos]

Well, seems like the mother-in-law didn't exorcise that pesky poltergeist. I noticed the two radiators not fitted with thermostat valves were getting unusually hot this afternoon and and can confirm that the Honeywell wireless room thermostat (DT92E) changed it's setpoint again - from 19C to 21C - without any human, cat or spiritual intervention (though I can't be certain of the latter!).

Setpoint change has happened several times since it was fitted around 5 years ago but I put it down to buttons being accidentally pressed/knocked. I suspect some other DT92E's units have the same problem but users probably explain away the automatic setpoint change in the same way I did.

I'm thinking of reasons for this occurring. Perhaps interference from other wireless devices? Few wireless devices are used regularly in this household - just the DT92E and associated hot water tank thermostat (CS92A) and the main boiler programmer (ST9420C). Other than the broadband router, positioned over 7 metres away, that's it. No Bluetooth either. There are some other wireless devices but they haven't been used in months and are turned off. And there are no fault symbols showing on any of the Honeywell devices. I shall contact Honeywell about this issue. I expect their response will be predictable, along the lines of: 'Never heard of that happening before. Someone must have changed the setpoint'.

If I were a tradesperson, I wouldn't be fitting any DT92E's to my customers' heating systems. There must be alternative options.

 

[MJN]

If I were a tradesperson, I wouldn't be fitting any DT92E's to my customers' heating systems. There must be alternative options.

Bit of an overreaction IMHO. They're a great stat, and I suspect yours just has something wrong with it. It's certainly not a common issue (even for you with a dodgy one by the sounds of it). Just replace it (for something completely different if you've lost all faith).

 

[dogfonos]

Just replace it (for something completely different if you've lost all faith).

I'd like to but can I mix & match these heating control devices? The Honeywell CS92A and ST9420C are working fine and I'd like to keep them. Is there another reputable branded wireless room thermostat that could replace the DT92E and communicate effectively with the other Honeywell devices? Thanks.

 

[MJN]

Yeah the DT92E is just a simple thermostat (arguably doing it a disservice with that title given its decent TPI implementation which maintains a very stable room temperature compared to many others) but I'll let others with wider product experience suggest alternatives. Personally I'd stick another DT92E in (actually I'd replace it with a programmable thermostat to combine time and temperature functions but that'd be changing the scope of the question).

 

[dogfonos]

Been investigating alternative wireless room thermostats to replace my troublesome DT92E and compatibility between brands is a minefield. Similar devices from more reasonably priced big names, such as Danfoss, have different wireless operating frequencies and, quite possibly, communication protocols too so it's a no go. I'm resigned to replacing the (expensive) DT92E like-for-like.

Thanks for your inputs.

 

[Mister Banks]

When buying a wireless thermostat you will be buying the receiver too so compatibility shouldn't be an issue.

 

[dogfonos]

An update...

Resideo suggested I factory reset the DT92E by entering installer mode so I did that on 13th Jan. Since then, the device hasn't automatically changed temp. setpoint - but it's only been six days. Time will tell. To be fair to Resideo customer services, they have made a real effort to get this wierd issue sorted, which I appreciate.