24 Dec - update - Grundfos pump still runs constantly

[Littlemiss21]

Blimey, 12 pages and 179 posts so far. This thread is giving those Brexit threads a run for their money!

I don’t know whether to laugh to cry anymore.

 

[dilalio]

Better to laugh until you cry

 

[Littlemiss21]

I’ve looked at the wiring junction pics - and I offer my apologies at this stage, that apart from the two orange wires being fed in together with the black in the same terminals, the rest of the wiring is a little over my head. I can understand the wiring on a s plan diagram, but dare not touch the wires. I only removed the wiring box cover (after powering down from the fuse spur) took the pics and quickly screwed it back on again.

 

[Littlemiss21]

Too many connections on the Switched Live to the boiler

View attachment 155078

Either the Brown or the Black goes to the Switched Live on the boiler. But where does the other one go to ?

Hi. Thank you for your message, the brown wire that you have kindly indicated with the arrow goes up to terminal where the yellow/green wire is - I think it’s visible on the first picture. Thanks again .

 

[Dan Robinson]

Hi. Thank you for your message, the brown wire that you have kindly indicated with the arrow goes up to terminal where the yellow/green wire is - I think it’s visible on the first picture. Thanks again .

It doesn't go into that terminal though.... Otherwise things would be going pop.

It goes to the flex next to the terminal which either goes to the boiler or the pump.

I'm surprised it's been installed as a switched live only. Sounds a bit pony to me.


I was going to suggest induced voltage causing the erroneous firing of the boiler and therefore pump. But this couldn't happen on a 3 wire set up. Nor have I seen it on a Vaillant ... Plenty on Shiessmann and Wooshitter though.

 

[Gasguru]

Unfortunately to see the wiring at the boiler end would involve removal of the outer case...and in the interests of safety that's not to be advised.
Assuming the pump is in the vicinity of the wiring centre can you follow the cable from the pump towards the wiring centre and confirm where the brown wire connects... ie. does it indeed connect to the orange termination.

 

[Littlemiss21]

Unfortunately to see the wiring at the boiler end would involve removal of the outer case...and in the interests of safety that's not to be advised.
Assuming the pump is in the vicinity of the wiring centre can you follow the cable from the pump towards the wiring centre and confirm where the brown wire connects... ie. does it indeed connect to the orange termination.

Hi Gasguru. Thank you. Yes, I draw the line at opening the boiler - that’s one thing that I def not dabbling in! . I’ve powered everything down again at the fuse spur and taken a pic of the pump cable leading into the wiring centre:

 

[dilalio]

I would leave it BG... They'll walk away if you've been tampering. You've come this far!

 

[dilalio]

As above, also check that any flex (cable) to the boiler isn't supplying both 240v and 24v (or other low voltage) in the one, shared flex. This can sometimes cause induced voltage on the other cores within the insulated sheathing.

I was going to suggest induced voltage causing the erroneous firing of the boiler and therefore pump. But this couldn't happen on a 3 wire set up. Nor have I seen it on a Vaillant ... Plenty on Shiessmann and Wooshitter though.

 

[Littlemiss21]

I would leave it BG... They'll walk away if you've been tampering. You've come this far!

Yes - that’s right. Apart from take these pics - I have not and will not touch the wires/wiring centre - health and safety and because I have no idea what I am looking at. It’s a matter of waiting, which like you rightly said I am leaving it to BritGas.

 

[Littlemiss21]

A BIG thank you to everyone for their input. I shall of course post the end findings on here...everyday is a school day - it will be nice to know the root cause of this fault.

 

[Dan Robinson]

That would imply I have read all the thread

 

[dilalio]

That would imply I have read all the thread

I have

 

[Gasguru]

It looks like the pump has not been wired to the boiler. AFAIR on some 4 series Vaillants this may have been acceptable? I wonder if the boiler pump and switched live terminals are connected together at the boiler end.

 

[petit_pablo]

It looks like the pump has not been wired to the boiler. AFAIR on some 4 series Vaillants this may have been acceptable? I wonder if the boiler pump and switched live terminals are connected together at the boiler end.

Wouldnt have had a pump live at boiler as previous boiler was a promax.

I'm surprised it's been installed as a switched live only. Sounds a bit pony to me.

Im not mad about the idea but vaillant say its ok on the new 400s.