Honeywell thermostat drops to 5 degrees

in_my_wellies

I noticed my heating had switched off - set at 20.5 degrees
I checked the digital display and it was reading 5 degrees and would not respond to my pressing the ^ button so I set it at manual which read 20 degree for two seconds then the numbers cascaded all the way to 5 degrees. I put it back to auto and it read 20.5 for two seconds then cascaded all the way down to 5 degrees again. It will not keep at the set temperature
Can anyone tell me if this is a problem with the the thermostat or the boiler please? Any easy DIY fixes? It dates from about 2007, I changed the battery at Christmas as the 'low battery' sign was flashing 
Why does this happen on Friday at 5 o'clock and not Monday morning???

JGB1955

What sort of boiler do you have?  We have a system boiler but know there is an unidentified  'leak' somewhere in the system.  So... when it loses pressure, the boiler shuts off.  Fill the system via the loop and everything is back to normal.

in_my_wellies

Hi thanks
It's a Baxi, It's sealed and I did have a pressure problem which was fixed last spring with a new tank inside it which looked like a metal hot water bottle (sorry for the technical description) The boiler is working and on, hot water is working. 

Bendy_House

Hi imw.

What thermostat? Where is it? What exact model is it?

Since you call it a 'Honeywell', I'm assuming it isn't part of the boiler? In which case, the system pressure will have no bearing on it.

It sounds kaput, but we need more info.

daveyjp

As above.  Sounds like a Honeywell wireless similar to ours, a CM927.

Does it also say 'room temp' or 'target temp' on the screen?

fenwick458

lots of issues with Honeywell stats like this, I've been to 2 jobs this week where the display has gone blank on the wireless ones, and have swapped 3-4 in the past 2 years for the same reason, they used to be good but apparently not.
also have problems with hive and nest, their all singing all dancing fancy looking smart stats sometimes last just over a year before breaking...
look at basic programable thermostats in comparison, these are bulletproof and used to cost £30 not to long ago before inflation went off like a rocket, and I've inherited one in both of my last 2 houses and they both still work, one must be 20 years old and the other is 11 years old. wonder how many of the new "smart stats" will be working 20 years from now?

in_my_wellies

Hi, thanks for your replies. We fixed it. The button which turns the heating down had stuck in. Once released the problem was solved. It is old and all the buttons have become a little unresponsive so it might be time for an update.
I'm tempted to get a Hive type as I can see it might be useful but given what fenwick458 says I might just opt for the basic like for like one he suggests. 
Would I need a heating engineer or an electrician? I'm assuming it's not a DIY job?

This one:

Bendy_House

Lol! Pleased it was something so simple to fix - once found - and that you sussed it yourself.

Is it a DIY job? Well, yes, a 'competent' DIY job.

There is actually a very good chance that you can simply unclip your existing ProgStat and clip in an alternative. These would need to be (like your current model) 'wired' types, and not WiFi. Hive make such a wired model - the SLT5 - but unless you can get it cheap on eBay, it's hard to recommend as it's stupid money new - around £160 for just the main unit?!

If you wanted to go for the 'usual' Hive - the 'Active Heating' jobbie - this is WiFi, so you'd need to fit the receiver in one of two places; the usual place is near the boiler, and then you can mount the control unit on the wall wherever you want., or even have it sitting on a stand. The simpler DIY method would be to replace your CM907 with the receiver - because all the wiring should already be there - and then you can ditto with your control unit.

If you want APP and remote/voice/Alexis control, you need to add a 'hub'.

Hive - £99 for the unit and receiver, or £170 to include the hub.

Are you happy with the control you already have with the Honey, or do you want App/remote control too?

Lots of recommendations for 'Wiser' too.

in_my_wellies

Thanks, I shall have to digest all that. 
When we were working, family, unpredictable hours, etc the remote control would have been brilliant but thinking about it my life is quite predictable these days so the basic wired model will is suitable. The repayment time for the upgrade would be quite a long time! 
Thank you 

getmore4less

Someone got the Wiser 2 channel pack for £99 a couple of days ago.

City plumbing still have some

Bendy_House

Imw has a combi, so a single-channel jobbie is the one he'll need.

I have to say, at just over £100, the Wiser seems the best value by some distance, as it seemingly has the control unit, receiver and hub all included.

£99 will only buy the first two items with Hive, and the hub is something like £70 extra. I do have a soft spot for the Hive, tho', and it's generally considered one of the most user-friendly to operate.