Central heating not coming on

Hi, I'm having an issue with the central heating not coming on. Bit of info about the boiler setup, boiler is an Ideal Classic SE15 FF, has a Horstman CentaurPlus C27 programmer, Honeywell tank stat and a Honeywell DT90e room stat. The light comes on, on the programmer for the central heating but nothing happens. Thinking that the room stat may of developed a fault, I got this swapped out under warranty today and fitted the replacement. Still nothing happening. Thinking now that the programmer may have gone wonky? Interestingly when the hot water is on the radiators are getting warm. Had an issue with the 3 way valve last year but changing the motor and freeing off the valve sorted it out. Would a faulty programmer cause the valve to get stuck in I presume the mid position? Or is it just coincidence that the valve may be worn out as well? Thanks.

A duff synchronous motor? It's a motorised switch which switches the pump on (IIRC)

Had to replace mine a few years ago with similar symptoms. Cost about a tenner from B&Q, and was able to do it myself.

It does sound like the 3 port mid position valve has seized up in the mid position. Thus also heating the radiator circuit aswell as the hot water. Imo new valve body plus actuator as it will seize up again.

Depending on what 3 port valve you have there should be a position indicator on the actuator telling you it's position. From this you can at least see if it moving when calling for heating hot water etc.

Just be careful if it has a plastic part on the switch lever, don't force it or you might snap it off like someone did to mine.

Try it again in December

The 3 way valve is a Honeywell, I changed the synchronous motor last year. Suppose it could have broken again. I've took the cover off and there is a bit of movement when calling for hot water. There's no movement at all when calling for heating. So is that the programmer bust or the motor? Does the programmer tell the motor which position the valve should be in?

Does the actuator have lights showing the relative position of the valve? Mine does.
Could be that when you replaced the motor you didn't solve the problem if the valve is seizing and it may actually burn out a motor if it won't move. Take it off and see how free the valve is with a wrench.




Obviously the wires are testable with a meter but only if you're proficient enough.

Unfortunately it doesn't have lights to tell you the position. I'll check if the valve is seized tomorrow. If it is, looks like a new valve is needed so we'll have to get a plumber in to do it.