Room thermostat CM927 for 24i Junior boiler?

[gubar]

Hi,

I have an older version of these boilers, which only have one temperature dial (combined heating and water - no seperate water control). It has no room thermostat but has a digital programmer like this one installed:

http://www.ebay.co.uk/itm/like/2808...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

I'd like to buy, and have an electrician fit, a CM927 like this one:

http://www.plumbarena.co.uk/product...gclid=CISDjfuvgMICFRMatAodb28AMw#.VGlAK3NFCv0


But I'm a little confused by a couple of things and would like to ask some questions please:

a) I have read that an optional diverter valve is required for some controls to work. Given that I have the digital programmer installed, does this mean I have the optional diverter already?

b) The CM927 has controls for hot water and heating, separately. My boiler doesn't - will this cause a comparability problem?

c) Would the CM927 replace, override, or work along with the digital programmer? They both have timer functions, for example.

If anyone could answer any of these questions I'd be very grateful - thanks!

g

 

[SimoninEaston]

I am no expert (which won't stop me posting on here... ) but I have just been trying to get more info. about my own WB 24i junior and I doknow that there are a lot of different older models - which one exactly is yours?[/b]

 

[gubar]

Hi,

I can check the documentation later on to see if that has an exact model number. In the meantime, here's are a couple of poor quality pictures, if that helps.

Thanks,

g

Untitled

• gubar
• 18 Nov 2014
• 1

Untitled

• gubar
• 18 Nov 2014
• 1

 

[D_Hailsham]

a) I have read that an optional diverter valve is required for some controls to work. Given that I have the digital programmer installed, does this mean I have the optional diverter already?

The Junior is a combi boiler, so it already has a diverter valve.

b) The CM927 has controls for hot water and heating, separately. My boiler doesn't - will this cause a comparability problem?

The CM927 only controls heating. But that is all you need as hot water does not need to be controlled because the Junior is a combi boiler.

c) Would the CM927 replace, override, or work along with the digital programmer? They both have timer functions, for example.

The digital programmer will have to be set to permanently on so the CM927 can take full control.

 

[gubar]

a) I have read that an optional diverter valve is required for some controls to work. Given that I have the digital programmer installed, does this mean I have the optional diverter already?

The Junior is a combi boiler, so it already has a diverter valve.

b) The CM927 has controls for hot water and heating, separately. My boiler doesn't - will this cause a comparability problem?

The CM927 only controls heating. But that is all you need as hot water does not need to be controlled because the Junior is a combi boiler.

c) Would the CM927 replace, override, or work along with the digital programmer? They both have timer functions, for example.

The digital programmer will have to be set to permanently on so the CM927 can take full control.

Hi,

thanks for the post. The manual for the 24i Junior combi boiler mentions an optional diverter valve, that's why I mentioned it. Also, the later editions of this boiler have separate controls for heating system temperature, and hot tap water temperature.

Apart from that - what you say makes it sound like it will work just fine. So I think I'm going to go ahead and order it - thank you.

thanks,

g

 

[D_Hailsham]

The manual for the 24i Junior combi boiler mentions an optional diverter valve, that's why I mentioned it.

Which manual is that? Can you give the GC number of the boiler it applies to (usually on the front cover)?

As I said earlier, combi boilers already have diverter valves, so I can't see why an extra one is needed.

 

[gubar]

Hi,

sorry, that point was actually mentioned on a page I read related to the thermostat itself, not in the manual. So I guess this means it will work.

You seem to have some knowledge of these things - do you know if this (cheaper) wireless thermostat would also work with my boiler:

http://www.mrcentralheating.co.uk/s...tat-st620wbc?gclid=CJzut7m6hMICFbCWtAodQC0AaA

Thanks again,

g

 

[D_Hailsham]

Yes it will work, but you should check with Salus and WB that the receiver will fit and plug in to your exact boiler model.

 

[gubar]

OK thank you - I'll get the exact model/part number at home tonight, and email worcester and salus.

Thanks,

g

 

[gubar]

Hi,

worcester have replied to me that a wireless thermostat "..as long as the control provides a 230V switch live back to the boiler."

The two I have looked at are specified as being volt free - does this mean that it does not fit the description above, or have I misunderstood the terms?

Thanks again

g

 

[D_Hailsham]

worcester have replied to me that a wireless thermostat "..as long as the control provides a 230V switch live back to the boiler."

The two I have looked at are specified as being volt free - does this mean that it does not fit the description above, or have I misunderstood the terms?

Both stats can provide 230V back to the boiler, but they need to be wired to do this. This is easy.

Some stats are internally wired so they provide 230V; others can provide any voltage. These are called "volt free".

 

[gubar]

Great, thanks again. An electrician is going to fit it for me so should be a simple job for him then.

Thanks

G

 

[ALCPlumbing]

I would get your plumber to do it if I were you. I don't like electricians touching any part of a heating system I've installed. They generally don't understand heating systems. At least that's my experience with them.

 

[gubar]

Thanks again guys. One last question please - there are many places online to buy these. Does anyone have a recommendation for a reputable online retailer for an item like this?

thanks,

g