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Dales-Electronic, HVAC Technician
Category: HVAC
Satisfied Customers: 1466
Experience:  I am a Home Appliance / Refrigeration Technician of 25yrs+ with my own business and for multi-brand national companies.
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Wiring a cm927 wireless room stat into avata plus

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Hello Mike here.

I could really do with some help wiring in a Honeywell cm927 into a remeha avanta plus 28c. I know this is really easy but I'm a bit new to the game and just needed a bit of help so I can move on with my career. Do I leave the current mechanical timer connected into x2 . And do the AB wires from receiver go to 7 and 8 on x9?.

OK a couple of quick questions, was the installation fitted with a mechanical thermostat prior to you wanting to connect a wireless one? If so which stat was it?
Customer: replied 2 years ago.
No. Boiler was only fitted with a mechanical timer. No thermostat. Hope this helps?
And thank you for responding
OK got you ~ in this case remove link between links 7 & 8 on X9 and connect Relay box R6660D wires to A & B obviously having already connected a fixed mains supply to the L & N terminals within. Leave the existing mechanical timer connected. Would you now kindly rate my service to you using the smiley faces below, this lets me close down the question whilst allowing you further information on a free of charge basis ~ Ian
Dales-Electronic and other HVAC Specialists are ready to help you
Customer: replied 2 years ago.
So simple??
Well I do thank you very much and appreciate your input.
regards Mike
Have fun
Customer: replied 2 years ago.
I assume the (broken) mechanical timer will need to be in the on position at all times?
Thanks again in advance.
OK what is it that you are trying to do here, you did not mention that you had a broken timer, so to explain, the timer is responsible for the on/off operation of the boiler whilst the thermostat is just responsible for looking after the room temperature. If you don't want to replace the timer then yes you will have to switch it on and off as required and leave the thermostat to control the room temperature.
Customer: replied 2 years ago.
Ok maybe I wasn't very clear.
The mechanical timer with all the little knobs on it does not work because of the plastic gears inside are probably Brocken. So setting the mech timer or using it with timed mode of course does not work. HOWEVER, the little switch on the mech timer does still work ie, when they want heating on they switch the little switch on mech timer to on position then heating works. They don't have a thermostat on or outside the boiler. They want a thermostat to control timed heating instead of replacing the cr4p mech timer all the time. Hence why I reccommended the single channel wireless room thermostat (honeywell CM927) so they can control the heating.
So, does this still make sense to leave the mech timer where it is still connected but in the ON position all the time so that the newly wired thermostat can work???
I'm happy to pay you for your efforts if you haven't already benifitted from this.!!! Just let me know how

Right I have to assume here that this is in a rented property (?) or is family as you refer to them as 'they' however, there is a replacement digital timer available for this model link follows or you could buy this on ebay which also throws up a spare pcb - for the same price.

Digital ~

Remember the thermostat only controls the temperature not the time and whilst switching it on manually controls the time if you forget to turn it off then you use up gas. Also (I assume here too) if you are a landlord you have a duty to provide working heating systems both time and temperature. But at least you have some suggestions as to a way forward ~ Ian

Customer: replied 2 years ago.
Ian, am I allowed to put my mobile no on here because it's best I talk you?
I'm aware that the thermostat controls the temp, but the cm927 is a single channel and thermostat right? Just asking why would I need the new digital plug in timer (which I initially thought of doing) if the temperature cannot be controlled which is what they want? to be able to control the temp. The cm927 will act as programmer and thermostat doesn't it??
Yes, rented property, family of 5.
I wondered why you wanted to do it this way but thought you were after the wireless rather than the timer. The way that the boiler normally would work as a stand alone unit is that hot water would be on demand whilst the central heating would be controlled by a timer with timed periods but would also cycle on and off using the boiler thermostat (usually preset by the manufacturer) during timed periods ie it measures the return temperature of the central heating water and switches on and off according to this. A more complex way of doing it is to control the room temperature with a room thermostat, thereby controlling the air temperature rather than the water temperature. Now it is usually more sensible to use the manufacturers time controls (otherwise you may end up doing more wiring) and then buy a separate thermostat (in your case a single channel either wired or wireless would probably be the best. Unfortunately, if you put in a telephone number the system blanks it out so that we engineers cant read it.
Customer: replied 2 years ago.
I understand all the above. Right, if I replace mech timer for digital timer (the one you reccommended) then to wire just a wireless roomstat ONLY is this done in the same way as you explained by removing link in 7 and 8 of x9 plug etc ??
What if I spelt out my mob no would that help? hahaha

You can sent it my email address if you like ~ dales.electronic(at) and I'll pick it up when I get to work tomorrow. Basically if you

get a base station that plugs into the connections already mentioned then a wireless one would work fine for you but you would have to be aware that the batteries would need changing from time to time.

Customer: replied 2 years ago.
Hi Ian
I emailed you last week with my no, did you receive it?
Still just waiting a response if you can Pls. Would be good chat about this situation. I'd be grateful.
Regards Mike
Customer: replied 2 years ago.
Hi Ian
I'm a bit confused as to youre reply??
Wanted to know if you received my email??
Pls let me know if I need to back off (hope not) as I still need your input regarding this matter

Give me an hour and I will be back on here, just heading off to pick my daughter up