how to wire in an overrun control to a worcester 40CDI conve

[n0rm4nb4rw1ck]

new to this forum .I hope some one out there can HELP. I have a Worcester 40CDI conventional boiler that kettles when central heating is switched of.I have been told to fit an overrun circuit to the system, this I have purchased,but I don't know where and how to fit it.It has a nice little circuit board with mounting holes and 4 coloured wires with LS to orange. N to blue. LP to red. LU to brown wire.I hope someone has been faced with a similar problem and is willing to pass on their knowledge.

 

[D_Hailsham]

But the Greenstar 40CDi Conventional boiler (GC NO 41-311-72) has built in pump over-run. The pump should be connected to terminal ST2.

If your boiler is kettling this is due to the build up of limescale, which says you are in a hard water area. Add one or two cans of Sentinel X200 to the system and the kettling will reduce.

 

[Dan Robinson]

Old ones had a separate module, but can't for the life of me remember how it was connected. Pretty sure it mounts the left side of the boiler (internally).

 

[n0rm4nb4rw1ck]

thanks for all the reply's I will check out your suggestions. I remember I was told that the problem would get worse with age. The reason why I purchased the overrun unit was because the Worcester engineer who fitted a new circuit board under the warranty said that it was needed. so presuming that he must have known it didn't have one I got one .I have had the boiler in use for 5 years now. it's reassuring to know that there are people out there willing to give up their time to help.Thanks again.....