Rcd tripping issue.

[Pauldicker]

Can someone shed some light on a problem I'm having.
I changed a CU today as there were only 6 circuits they are all now rcbo's there was no rcd protection prior to that.
On the ground floor circuit the rcd test was x1@ 147ms and x5@ 23ms.
However now when the customer turns the heating on its fine and if they turn the hot water on at the same time it's tripping the rcd.
It is run from a fused connection unit and upon looking all looks good in the fcu.
It's a valiant ecotecplus 618 and the controller is a lifestyle lp522
I'm not a heating engineer but I may be missing something obvious.

 

[Pauldicker]

more than likely as the boiler needs l n e and sl. With out knowing what plan it is etc its just guess work. But I would bet changing the programmer is going to achieve sweet FA.

Well its the cheapest option the customer wanted to start at.

 

[Midwest]

more than likely as the boiler needs l n e and sl. With out knowing what plan it is etc its just guess work. But I would bet changing the programmer is going to achieve sweet FA.

Yep kinda agree with you there.

 

[Midwest]

Well its the cheapest option the customer wanted to start at.

Doubt the programmer, is gonna be the cause of the problems. If it is internal, is going to be a pump, valve or something. From a distance, it sounds like the boiler been added to a dogs dinner of external wiring, to room stat & cylinder stat. Have you checked them for faults?

PS Or even the wiring in the box behind the programmer, pinched cables?

 

[Pauldicker]

Yep kinda agree with you there.

Guys as usual your advice is very much appreciated and that im happy that its not anything i have done as all i did was change the CU and put in an RCBO. I believe that there was possibly a fault prior to me changing the CU and it has only surfaced as there is now fault protection.
Your opinions are valued and appreciated.

 

[Pauldicker]

Doubt the programmer, is gonna be the cause of the problems. If it is internal, is going to be a pump, valve or something. From a distance, it sounds like the boiler been added to a dogs dinner of external wiring, to room stat & cylinder stat. Have you checked them for faults?

PS Or even the wiring in the box behind the programmer, pinched cables?

Wouldnt know where to start

 

[Leesparkykent]

Can't see how that works, as it appears to have an internal diverter value.

if it piped as a four pipe system.

 

[Midwest]

Guys as usual your advice is very much appreciated and that im happy that its not anything i have done as all i did was change the CU and put in an RCBO. I believe that there was possibly a fault prior to me changing the CU and it has only surfaced as there is now fault protection.
Your opinions are valued and appreciated.

Happy hunting, hate fault finding

 

[Pauldicker]

Guys as usual your advice is very much appreciated and that im happy that its not anything i have done as all i did was change the CU and put in an RCBO. I believe that there was possibly a fault prior to me changing the CU and it has only surfaced as there is now fault protection.
Your opinions are valued and appreciated.

And the fact it blew a 3amp fuse only seems to make sense.

 

[Pauldicker]

Happy hunting, hate fault finding

Im going to tell them to get a valliant registered engineer.

 

[Leesparkykent]

Well its the cheapest option the customer wanted to start at.

The cheapest and best option would be to find and diagnose the fault instead of changing random components. I agree with Midwest the wiring looks shyte so that would be a good place to start. With a multi meter it should take no more than about 10 minutes to find.

 

[Leesparkykent]

Im going to tell them to get a valliant registered engineer.

or a competent electrician

 

[Midwest]

Scratching my head to understand how this system works? If it is a combi, there's no cylinder and therefore no cylinder stat and associate wiring. External programmer feed to room stat , and switch wire back from stat to boiler along with permanent live and neutral? So if that wiring IR's out okay? Fault has to be in boiler, unless behind programmer??

 

[Leesparkykent]

Scratching my head to understand how this system works? If it is a combi, there's no cylinder and therefore no cylinder stat and associate wiring. External programmer feed to room stat , and switch wire back from stat to boiler along with permanent live and neutral? So if that wiring IR's out okay? Fault has to be in boiler, unless behind programmer??

It will be a system boiler not a combi hence the two channel programmer. System boilers are generally used on unvented/sealed fully pumped systems. The only difference from a sparkys POV will be that the pump is internal to the boiler not external.

 

[Wilko]

Hi - just having nice cup of tea and reading this interesting post. Without seeing anything and tin hat on etc : trips when hot water asked for ... I'm liking the 2 port valve? As Lee says, there's likely 2 two port water valves near hw tank, one for supplying heating and one for hw. And a boiler with its own internal divertor valve and pump (sorry, I'm just imagining the set up there). Both the 2 port valves have moving parts, water and power connected and so may cause current leakage? I've not had a valve do this to me, but it would be any easy one to check if you're onsite. Anyway, I would ramp test the new RCBO to see exactly what current fires it and then start measuring the earth leakage current for the circuit - step by step. Hope that helps. Cheers, David.

 

[Midwest]

It will be a system boiler not a combi hence the two channel programmer. System boilers are generally used on unvented/sealed fully pumped systems. The only difference from a sparkys POV will be that the pump is internal to the boiler not external.

Thanks for the explanation