IR Testing on a radial FC with Combi Boiler

[newtothis]

Combi boiler on a dedicated radial circuit, has a FCU no neon with a 5amp fuse.
Any special precautions need to be taken before applying 500V DC?

Thanks in advance for any advice

 

[telectrix]

as long as the FCU is double pole, just switch it off before testing.

 

[davesparks]

Normally it would be an sfcu rather than fcu for a boiler, or is that what you meant? Sfcu being switched fused connection unit, fcu being (unswitched) fused connection unit.

The short answer to your question would usually be switch the sfcu off, plus checking that the sfcu is double pole if it's an older one. More modern sfcu should be double pole and so will disconnect both L and N allowing safe testing.

For a fcu it's worth disconnecting the neutral as well as removing the fuse to be certain.

You are testing the fixed wiring not the appliance itself.

 

[newtothis]

Thanks - Yes it's a SFCU, I appreciate the correction.
Getting the terminology right will help me to ask better questions.

It is old, I'm not sure if it's double pole will check, if it's not I will change it.
That question was about my boiler, thanks very much.


With reference to a current question on the main forum.
I have a purley academic question.
http://www.electriciansforums.co.uk...ma-rcd-tripping-after-replacing-consumer.html

Someone connected a boiler to a new CU and it tripped the RCD.
If testing was carried out prior to fitting the new consumer I don’t believe this fault would have been picked up. I suspect possible water ingress, via the flue.

How is this situation handled, is it by informing a customer that vital appliances my not work after CU update ?

 

[Leesparkykent]

Thanks - Yes it's a SFCU, I appreciate the correction.
Getting the terminology right will help me to ask better questions.

It is old, I'm not sure if it's double pole will check, if it's not I will change it.
That question was about my boiler, thanks very much.


With reference to a current question on the main forum.
I have a purley academic question.
http://www.electriciansforums.co.uk...ma-rcd-tripping-after-replacing-consumer.html

Someone connected a boiler to a new CU and it tripped the RCD.
If testing was carried out prior to fitting the new consumer I don’t believe this fault would have been picked up. I suspect possible water ingress, via the flue.

How is this situation handled, is it by informing a customer that vital appliances my not work after CU update ?

ideally he should of broke the controls down to find the fault..probably a dodgy valve that's leaking...once the faulty component was found he should inform the customer. If the customer wasnt willing to have the fault rectified/dodgy component replaced then I would of put the heating system/controls on a plug top and then it would be down to the customer whether they plugged it in, on my advice not to.

 

[newtothis]

ideally he should of broke the controls down to find the fault..probably a dodgy valve that's leaking...once the faulty component was found he should inform the customer. If the customer wasnt willing to have the fault rectified/dodgy component replaced then I would of put the heating system/controls on a plug top and then it would be down to the customer whether they plugged it in, on my advice not to.

Hmmm I'd be well out of my comfort zone there :thinking:. I was half hoping someone would say going inside gas boilers, is above and beyond the call of duty ?

 

[Leesparkykent]

Hmmm I'd be well out of my comfort zone there :thinking:. I was half hoping someone would say going inside gas boilers, is above and beyond the call of duty ?

The op of that thread said it has a 3 port valve so its a Y-plan. Being a Y-plan the programmer, room thermostat, cylinder thermostat, pump,3port valve and wiring centre are going to be external to the boiler.

 

[davesparks]

Someone connected a boiler to a new CU and it tripped the RCD.
If testing was carried out prior to fitting the new consumer I don’t believe this fault would have been picked up. I suspect possible water ingress, via the flue.

How is this situation handled, is it by informing a customer that vital appliances my not work after CU update ?

Personally I doubt I would have picked it up before turning it back on as it would have been isolated for the testing.
Water ingress via the flue shouldn't get in to the electronics, unless the boiler is very broken or the flue installed incorrectly.

The best way to handle it is to discuss the job with the customer beforehand and explain that faulty appliances may become apparent with testing/adding RCD protection. Then also putting a disclaimer on the quote/contract to cover your rear end.
I, and I'm sure most electricians, have been caught out in the past and learned from it.

 

[davesparks]

Hmmm I'd be well out of my comfort zone there :thinking:. I was half hoping someone would say going inside gas boilers, is above and beyond the call of duty ?

Going inside a gas boiler is a much debated subject, the last official line I heard was that an electrician may carry out work on a boiler as long as it does not break any gas seal or affect the flow of and gas (fuel gas, air, flue gas) so basically you can normally access the terminal chamber to connect/test. But if in doubt then it's best to get a gas safe bloke to advise.

I work with a local plumber regularly and have taken the time to learn the basics of plumbing and gas work, which I think is advisable for any electrician doing heating systems.

In my opinion you need to understand what the controls you are wiring are doing and why they do it. There are a lot of electricians who just follow the 'paint by numbers' wiring diagrams and get completely lost when faced with anything that doesn't resemble a standard system.

 

[newtothis]

Thanks again Dave, I'll have to give this all some very serious thought.

 

[davesparks]

Thanks again Dave, I'll have to give this all some very serious thought.

No worries, ask as many questions as you need to