Worcester Bosch Greenstar Ri boiler short circuit

[Michael Groves]

I’m an electrician. I’ve been called to customer home to trace a short circuit. When I disconnect the boiler and put my meter across live and neutral I get 118 ohms.
I called Worchesterbosch tech support and the guy said yes that’s normal, no hold on I’ll ask my mate. Then apparently said no it’s faulty.
Customer has contract with British Gas so engineer attended. Customer took a picture of me testing to show engineer. Engineer said I’m not an electrician, I don’t understand. But it’s all fixed and left. When I checked fault was still present.
Another engineer followed, he put a meter across terminals with red and green lights, cut back some cables in control box and said its fixed. I returned same fault.
Seriously, is it normal for a gas engineer not to be able to do a simple continuity check?

Anyway, is this normal for this type of boiler?

 

[bacon_sandwich]

Assume boiler is tripping MCB, hence your short cct statement. If there are no other loads on that cct, then it points to boiler or associated devices. If you cannot get a decent IR to earth from live to trace individual components then i would disconnect all associated loads, like pump and any zone valves and see if the fault is still present with just the control board connected, if you still have a fault i would probably replace control board. Zone valves and pumps should test properly with IR.
Hope this helps

 

[Michael Groves]

Boiler is not tripping, the reading came up on EICR. Everything seems to be working fine. I've isolated boiler from circuit so it must be coming from boiler or upstream devices (valves etc).

I don't want to get involved in fixing the problem, I just want to be able to give customer confidence it has either been fixed or this reading is normal. At the moment British Gas engineers don't give me any confidence at all. As a GSR engineer would you expect another GSR engineer to perform the tests you advise above?
Would you expect to see 118 ohms across terminals normally?

 

[Murdoch]

Boiler is not tripping, the reading came up on EICR. Everything seems to be working fine. I've isolated boiler from circuit so it must be coming from boiler or upstream devices (valves etc).

I don't want to get involved in fixing the problem, I just want to be able to give customer confidence it has either been fixed or this reading is normal. At the moment British Gas engineers don't give me any confidence at all. As a GSR engineer would you expect another GSR engineer to perform the tests you advise above?
Would you expect to see 118 ohms across terminals normally?

Hum. Switch off boiler and redo IR test - are you doing L&N to CPC or L-N, L-E & N-E?

............... I would suggest the boiler isn't part of the fixed wiring - like a cooker..........

Next

 

[Michael Groves]

Some background information, previous spark did EICR but did not give customer paperwork and has been paid. Ran out the door saying short on ring main, I'll be back...…….. That was a few months back. I've told customer to get paperwork otherwise I need to completely redo tests which means paying twice.
I've not performed an IR test at the moment, I'm hoping customer will get EICR so I can fully review and rectify all faults in one go.

I've only completed continuity tests, L&N - 118 ohms, L&E - open, N&E - Open. On this circuit only.

I agree boiler not part of fixed wiring, so not my responsibility. I don't want to get involved other than ensuring someone fixes it or documents this is normal operation.

 

[bacon_sandwich]

Couple of things. EICR ends at the boiler FSU. 118ohm is not a short cct, its not even odd and i would not even have measured it let alone queried it. At DC it represents a current of 2A so well within expected as a boiler is typically fused at 3A. As you do not know the components inside the boiler or even if the pump is across the load as well, thermostats and zone valves, it is a pointless reading and serves absolutely no useful purpose.

 

[bacon_sandwich]

Oh, should have mentioned, i am an electrical eng as well as GSR

 

[Murdoch]

Some background information, previous spark did EICR but did not give customer paperwork and has been paid. Ran out the door saying short on ring main, I'll be back...…….. That was a few months back. I've told customer to get paperwork otherwise I need to completely redo tests which means paying twice.
I've not performed an IR test at the moment, I'm hoping customer will get EICR so I can fully review and rectify all faults in one go.

I've only completed continuity tests, L&N - 118 ohms, L&E - open, N&E - Open. On this circuit only.

I agree boiler not part of fixed wiring, so not my responsibility. I don't want to get involved other than ensuring someone fixes it or documents this is normal operation.

Your approach to EICR's is completely wrong ........ its an inspection and test only .......... not a work creating scheme with lots of remedial works .

I don't care if the customer asks somebody else to do remedials - in fact I think its better if somebody else does them.

 

[bacon_sandwich]

I think he is hoping the EICR will turn up with remedials documented, so he can just carry out those remedials.

 

[Michael Groves]

Couple of things. EICR ends at the boiler FSU. 118ohm is not a short cct, its not even odd and i would not even have measured it let alone queried it. At DC it represents a current of 2A so well within expected as a boiler is typically fused at 3A. As you do not know the components inside the boiler or even if the pump is across the load as well, thermostats and zone valves, it is a pointless reading and serves absolutely no useful purpose.

We are in agreement about EICR ending at FSU.

Just for clarity, you would always expect to see a small reading across terminals, no matter what boiler?

 

[Michael Groves]

Your approach to EICR's is completely wrong . its an inspection and test only . not a work creating scheme with lots of remedial works .

I don't care if the customer asks somebody else to do remedials - in fact I think its better if somebody else does them.

I think you have misunderstand the post. I agree an EICR is a test only. I also agree your second comment.
To repeat, someone has apparently completed an EICR and highlighted some faults. However, the spark has not produced any paperwork. I've asked the customer to get the report to save him money.
Post back if it still does not make sense. Albeit watch out for a similar post on our forum with more content, you might prefer to post back on this.

 

[Murdoch]

^^ I simply don’t understand what you were trying to achieve by such a “test”

 

[Michael Groves]

Customer said previous spark found a short on ring. A quick continuity test showed 118 ohms across live and neutral. Quick unplug and this disappeared on ring, and showed up on boiler. I've now had confirmation this is normal so case closed on that.
Like I say I'm still waiting on EICR, maybe IR test might show something else on ring, but it will be cheaper for customer to get EICR, rather than pay me to do one, as they have already paid for it.

 

[Michael Groves]

I’ve alerted the media, I’m going for film rights ££££

 

[bacon_sandwich]

We are in agreement about EICR ending at FSU.

Just for clarity, you would always expect to see a small reading across terminals, no matter what boiler?

As i said before, the reading is of no relevance, i do not measure continuity between LN on a cct board for a boiler.
The outgoing LN from the FSU is generally wired directly to the LN input on the boiler control board. The board has a number of loads that often, but not always , flow through the board, e.g. exhaust fan, gas valve, temp sensors, spark inductor, often pump, etc. The actual state of all these loads as presented to the board when it is powered off and you have connected your meter is unknown, therefore the reading cannot be used for anything meaningful. Unless the reading is 0.0 in which case breakers will have tripped. As mentioned , if pump or valves are suspected, these can be isolated and tested separately using IR L to E and/or N to E.
Give it up please, lol

 

[bacon_sandwich]

Oh forgot to mention, often, but not always, a remote time clock/programmer and zone valves pull power from the same boiler FSU, if the thermostats are calling for heat you will be measuring the zone valve motors and programmer to boot, hence not a worthwhile test. If you do go at it with your meter on IR, please set to 250V as thermostats and boiler control board will get fried at 500V.....eek

 

[Murdoch]

I’ve alerted the media, I’m going for film rights ££££

I was going to give you a dumb but they aren’t on this forum

Shame

 

[Michael Groves]

I was going to give you a dumb but they aren’t on this forum

Shame

Yeah, wrong post, I would have deserved it...………………..