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Thermostat for Combi Boiler

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chips

Newbie
Have a Worcester Bosch Combi Boiler controlled by a Honeywell CM921 wireless thermostat.

The button on the thermostat seems to have no effect when pressed so I'm guessing I need a new thermostat?

The CM921 is no longer made and a T3R looks a viable replacement but it's £75 ish.

Can anyone recommend a cheaper one that will do the same thing, or a way to get the button on the CM921 to work again, cheers
 
chips said:
Have a Worcester Bosch Combi Boiler controlled by a Honeywell CM921 wireless thermostat.

The button on the thermostat seems to have no effect when pressed so I'm guessing I need a new thermostat?

The CM921 is no longer made and a T3R looks a viable replacement but it's £75 ish.

Can anyone recommend a cheaper one that will do the same thing, or a way to get the button on the CM921 to work again, cheers
Click to expand...
You can get a cheap roomstat, programmable that will do the same job
 
Have you changed the batteries?
Have you checked the manual for troubleshooting?
Have you googled possible fixes?
 
I can't recommend a cheaper one mate but (to quote another members status on here, cheap won't be good and good won't be cheap) I have installed a Honeywell Evohome system, with HR92 radiator valves. I can't speak highly enough of this system, essentially (in a nutshell) what it does is turn every single room/radiator into its own zone, so no longer am I heating upstairs when no one is up there. Livingroom cold - the livingroom radiator will come on, hallway cold but livingroom warm or at the temperature I have set, the hallway radiator will come on, no others, A great purchase IMO
 
Kaspas4450 said:
I can't recommend a cheaper one mate but (to quote another members status on here, cheap won't be good and good won't be cheap) I have installed a Honeywell Evohome system, with HR92 radiator valves. I can't speak highly enough of this system, essentially (in a nutshell) what it does is turn every single room/radiator into its own zone, so no longer am I heating upstairs when no one is up there. Livingroom cold - the livingroom radiator will come on, hallway cold but livingroom warm or at the temperature I have set, the hallway radiator will come on, no others, A great purchase IMO
Click to expand...
That sounds a great system to have now that the price of energy has soared out of control. I turn the radiator valves down to 1 in the rooms I don't use in an effort to save a few quid.
 
bigwig21 said:
Have you changed the batteries?
Have you checked the manual for troubleshooting?
Have you googled possible fixes?
Click to expand...
Yes have changed batteries not so long ago but will try a new set. No word on this in the manual. Have googled the problem and it's either take the thermostat apart and clean the contacts between the button and the contact or do a re-set. Will give the take apart and clean a try, thanks.
 
chips said:
That sounds a great system to have now that the price of energy has soared out of control. I turn the radiator valves down to 1 in the rooms I don't use in an effort to save a few quid.
Click to expand...
The radiator valves that you have are probably the wax filled ones, they are not great and have a very short life, turning them down if they are old will probably do nothing other than restrict the flow of water to the radiator, they certainly won't monitor the temeperature of your room and adjust. The system above is mechanical, and they will physically turn on and off the radiators, they even detect if a door or window is open and adjust accordingly, they can even (because they are wifi connected adjust for the outside temperature). The system is not cheap, I think I paid around £700 for it, but it has paid for itself in about 6 months
 
Personally I wouldn't fit anything other than Honeywell.
I'm not sure of your particular model, I will Google it in the morning and get back to you, it's probably just a different number to what I use, they use different numbers for trade and DIY, even for the exact same thing.
 
steptoe said:
Personally I wouldn't fit anything other than Honeywell.
I'm not sure of your particular model, I will Google it in the morning and get back to you, it's probably just a different number to what I use, they use different numbers for trade and DIY, even for the exact same thing.
Click to expand...
I have HR92 Radiator Valves
 
Kaspas4450 said:
But.... you need the reciever wired into your boiler by a cerified Gas Safe Engineer, (especially if you have central heating insurance) the rest you can do yourself
Click to expand...
Why,?
You are not entering a gas compartment, I believe any COMPETENT person can do this, how a DIYer can prove competence I'm not sure.
btw, any competent person can undertake gas work in their OWN home.
 
I have the T3R , works fine , easy to operate , I only have 4 time time periods per day on mine , I’d prefer 6 but it works. Has different settings for weekend as well.

@kaspas , what type of boiler do you have ? It sounds like it would be expensive for a combi system.
 
steptoe said:
Why,?
You are not entering a gas compartment, I believe any COMPETENT person can do this, how a DIYer can prove competence I'm not sure.
btw, any competent person can undertake gas work in their OWN home.
Click to expand...
@steptoe and @Scufferoo You are right mate, I could have wired it in myself, but I would not be classed as a Competant person in the eyes of the insurance company, and if I did it myself then my Boiler and Heating Insurance would have been void, as it wasn't fitted by a Gas Safe Engineer, it only cost £40 to have it wired up. I only have a Ideal Logic Boiler, and yes it is an expensive system, but not as expensive these days as heating the whole house when there is no need to.
 
@chips
just had a google, I have fitted loads of those stats, usually very good and reliable, I've never known one to fail in the way yours has.
In fact, I probably have a couple kicking about in my shed/store, but I wont be back in the UK until just before Xmas.
I know its expensive, but I would personally recommend the T4R, or if it possible to hard wire then a normal T4
if you need a wireless stat then these are usually fairly reliable, I actually have a Salus in my own house, albeit hardwired.

Salus Logic Plus/Vogue RT510RF+ programmable boiler plus room thermostat | Wolseley
 
I have a NEST thermostat, I rate it highly,

You can control it from your phone. I set different temperatures at different times during the day, and has geo fencing, so switches off when you leave the house. Also, links to the smoke detectors, if it senses carbon monoxide it will shut off the boiler.

Only negative for me is, my boiler doesn't support Opentherm, so doesn't modulate the radiator temperatures.(vailant)

We had new boiler installed, so I brought one at same time.
 
IMHO
NEST are a PoS
I have fitted loads for landlords, nothing but hassle.
I used to make it very clear to them that once fitted and verified as working once I left it would be £200 callout to return as they just aren't worth the trouble for dropouts on WiFi.
A good idea, but shit Implementation.
 
steptoe said:
IMHO
NEST are a PoS
I have fitted loads for landlords, nothing but hassle.
I used to make it very clear to them that once fitted and verified as working once I left it would be £200 callout to return as they just aren't worth the trouble for dropouts on WiFi.
A good idea, but shit Implementation.
Click to expand...
mines hard wired to the boiler, not had any issues 3 years in.
 
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