Wiring Alpha boiler to Honeywell Y Plan

3 Nov 2005
Reaction score
Newcastle upon Tyne
United Kingdom
I have just had a new Alpha CD24R boiler fitted (by a COTGI fitter) but his electrician made a complete hash of the wiring - twice. I am waiting for another sparky to come but after my previous experience I'd like to know what the wiring should be. The boiler is to be wired in to an existing (and working) Y Plan with room and cylinder stats and mid-position motorised valve. These are wired into a 10 terminal junction box according to the Honeywell diagram. The problem is the conections from the boiler. I called the Alpha helpline (twice) and got the same advice -"only one wire goes from boiler no. 1 to j box no. 8, and nothing else connected." However this leaves terminal 1 on the room stat and terminal C on the cylinder stat not connected to anything. The boiler has an Alpha internal digital programmer fitted but I suspect that the Alpha helpline didn't listen and assumed that there was an external programme wired in.
Can anyone tell me the connections between terminals 1, 2, 3 and 4 on the boiler block and the standard Honeywell junction box.
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local