Worcester Bosch Pump overrun

[DEMPSEY1965]

Hi

Can you help?

My greenstar 12ri has been banging away on heating sutdown and have discovered that it has no pump overrun. What I would like to know is, is it a case of changing a few wires around? If so how difficult is it?? Ant help and diagrams would be greatly appreciated. The wiring panel has 12 terminals if that is any use lol.

 

[dancinplumba]

hi, check the MI's they will tell you

 

[tweakyboy]

I'm guessing who ever has wired the boiler hasn't wired it to the boiler?

You need to run a wire from the boiler to the pump, inside the boiler there are some terminals for you to be able to connect the pump to it.

Just digging out a link for the wiring diagrams.

 

[tweakyboy]

http://www.worcester-bosch.co.uk/cache/file/482/gas-boiler-wiring-guide.pdf Download this link by right clicking...

 

[DEMPSEY1965]

Many thanks for this although I think it might be beyond me. Do the original wires in the terminal block stay the same or does everything switch around?

 

[tweakyboy]

You should have a heating engineer around to have a look at the job, its straight forward to wire up but its getting a wire from the boiler to the pump.

Have a professional take a look, saves aload of grief if you manage to misplace a wire or two!

 

[GasmanxxxR1]

If the cable going to the boiler is a 5 core then its only a 5 min job to rectify

 

[DEMPSEY1965]

Typical! There are 3 cables, 1 which is obviously the timer and the other 2 have a black/brown/grey/earth in. The boiler is directly under the airing cupboard so routing a new wire isn't too much of a problem,really just the wiring afterwards.

 

[GasmanxxxR1]

Youve got all the cables you need then.

The wiring diagrams are in the boiler manual.

Need to be GSR to take the case off the boiler though

 

[GasmanxxxR1]

Who installed it, might not be wired up correctly in the boiler or wiring centre

 

[DEMPSEY1965]

Yes think I will get someone in,so the 3 cables are for the boiler, timer and the pump?

 

[DEMPSEY1965]

Right, the wiring is a mess but everything works fine though,just need to sort out wiring for the pump overrun to work. Ihave studied the Drayton wiring diagram and the 3 grey wires do not add up. I wonder if there is a clever person who can fatham them out for me then I can sort everything out. The 3 grey cables each have 3 core and earth which come from downstairs. 1 of them is from the timer which is wired strange and the other 2 from the 2 boiler terminals. Grey cable 1 has the black connected to neutral,brown to live and grey to the yellow of the tank stat and orange of the motorised valve and brown of the pump. Cable 2 has the black connected to the neutral,brown to live and the grey cable to the brown of the tank stat and grey of the valve. Cable 3 has the brown to live,black to neutral and the grey to the blue of the tank stat. If you could tell me which cable is connected to which then I would be most impressed and extremely grateful.

Many thanks.

 

[DEMPSEY1965]

Here is the diagram if you can make sense of it.

 

[Mike Jackson]

Looking at the diagram all three grey wires have connections that should run back to the programmer. I'd guess that the boiler is close to the programmer and is wired via that.

If the system is working okay apart from the pump over run issue then what you need to do is take the brown wire from the pump out of the terminal with the orange wire and somehow extend it back to the boiler and connect it to the pump live connection on the boiler. There may be a way of doing it utilising the existing wiring but without looking at it in person i couldn't say.

 

[larsson67]

check that the boiler is on a permanent live and not a switched live , i had a problem last year when the sparky wired up a new 18ri and new controls wrong so the boiler was powered by the switched live not allowing the pump overrun and causing the boiler to go to lockout

 

[DEMPSEY1965]

Ok guys thanks a lot for all your help,I appreciate your time.

 

[DEMPSEY1965]

Yes Mike is right,the boiler is wired to the programmer which is next to it. From the diagram is there anyway of enabling the overrun from the wiring terminal?

 

[DEMPSEY1965]

Hi Mike,

Just gone back to the wiring having left it for a while. I have sort of solved the riddle of the overrun. From what you have said about taking the brown from the pump and connecting it to the live pump on the boiler I need to find which one of the 3 grey cables has the pump live in it. From working out which is which, one brown is to the timer,one brown goes to the boiler live and one brown to the pump live. At the wiring terminal I can find the timer live by just taking one of the browns from the grey cables out to see when the timer has no power. So the other 2 browns will be the pump live and boiler live,will it be ok to remove each in turn and connect it to the live on the pump in a spare terminal on the block to see which is which without blowing anything up? If I connect it to the boiler live then the pump will just run all the time and I know it will be the wrong one. I know I am crazy but sometimes it is more rewarding if you solve these things yourself (with help from clever people).
Many thanks for your help.

 

[Roger Welton]

Its also worth making sure there is a bypass on the system, so the water can be pumped somewhere after everything has shut down!, It should be located between the pump and control valves.

 

[DEMPSEY1965]

Ok Roger,many thanks so my wiring will be ok from what I have said?

 

[dancinplumba]

grey wire of wire 1 is pump overrun, this should have feed from boiler me thinks

 

[DEMPSEY1965]

Yes that was what I was going for,just need to find the feed from the boiler,it's 1 of the 3 brown wires,it should go to the live pump on the boiler.

 

[Mike Jackson]

If it were me I'd just take one wire out at a time and see what stops working. Be careful not to leave the boiler running too long without the pump on but the overheat willl prevent damage. If removing just one wire stops the pump but the boiler still fires and the 3 port opens then you're onto a winner.

 

[DEMPSEY1965]

Sorted,just removed 1 wire at a time to find the pump feed from the boiler and got it second time. I then connected it to a spare terminal along with the live from the pump and everything is ok. I have a pump over-run! Can I take this opportunity to thank all of you who have helped me along the way and sorted this problem. Not only have you saved me a hell of a lot of money but also it meant I didn't have to damage my utility room by removing tiles etc to trace the wires. I really appreciate this and keep up the good work.

Many thanks again.

Regards

DEMPSEY1965

 

[Mike Jackson]

Glad you got it sorted and thanks for letting us know.

 

[DEMPSEY1965]

I don't know if the message will have got to everyone who helped,if not can you tell me how to do it plz,I just want to thank everyone for their input.

Regards