Installing a CM927 with a 2 channel system

[stuarty1234]

Hi - I am about to get a new boiler (moving from oil to gas) and I would really like to get a Honeywell CM927 thermostat work with my system which currently has separate controls for HW and CH, my plumber isn't to confident on how to get this to work

I have read previous posts on this issue but I am unclear on the exact details and any links to Honeywell documents mentioned in these threads are now inactive (Honeywell Application Guides Nos 109 and 110) - does any one know where I can get a copy of these?

I had a CM927 in my last house and loved how it worked although this was with a combi boiler

My system is currently controlled by a Centaurplus C21, I have a thermostat on my hot cylinder and a wired thermostat in my hall but I really like the ability to vary the temperature at different times of the day - i know the CM927 is only single channel but can I control the HW using my existing Centaurplus and the CH using the CM927? If so is this type of system documented somewhere so I can show it to my plumber

Or is there something similar to the CM927 out there that I can use instead?

Any advice given would be greatly appreciated

Thanks in advance

 

[Dan Robinson]

It is a piece of Plss. If your installer can't work it out - get another installer.

You can use your existing timer for hot water. If the stat on the wall is in an OK position, save some cash and change it to the CM901 and reuse the wires. If dummy plumber wants to make it easier he can just leave the timer's heating channel on constant.

But seriously if he can't figure that out himself it is time to look elsewhere

 

[vicvapour]

Not too sure if you can get a wireless 2 channel programmer is thats what you are after.

Does it have to be wireless?

 

[MJN]

As Dan, this exact setup (CH programmer, seperate HW timer) is extremely common so you really do need to sack the plumber pronto as one ought to be suspect of what other incompetences he might have.

My own system uses a CM927 for CH and a Sangamo PSW timer for the HW which I can definitely recommend. Whilst I could've reused the timer function of the previous all-in-one Siemens CH/HW timer I opted to replace it to keep things nice and simple (and the sale of the Siemens paid for the Sangamo so it was a win/win situation).

Mathew

 

[vicvapour]

Is the plumber Part P registered?

If he is fitting the the controls he would have to be as this notifiable minor work.

source:
PART P:
DOMESTIC ELECTRICAL SAFETY
April 2006 Revisions
(modified April 2007)

 

[stuarty1234]

Thanks for the responses - I have got it sorted, I think there was a bit of confusion between me and my plumber with what exactly I wanted all sorted

Thanks again