Testing of central heating control wiring

[elementps]

Hi all,

Just after some advice on the testing of central heating control wiring.

Obviously the fused spur feeding you boiler will be tested within the installation.
From reading, I have become aware that the control wiring is covered by part p, there is also an option for this when submitting work online.

Could anyone shine a light onto the extend and requirements for testing the controls? And how would these tests be certified, is there a specific certificate?

Many thanks

 

[GT1]

I would only test up to the fcu of the boiler. Anything after that and you risk damaging pcb's and boiler electronics.
Part P comes in because some work on heating is notifiable, ie new installations. However beyond the fcu you leave behind "permanent" installations, and thus the rules on verification/testing.

 

[Deleted member 26818]

If there is a wired thermostat, then that would be covered by Part P.
Anything in the boiler itself is outside of Part P or your responsibility.
Be very carefull about conducting any tests on thermostat wiring, make certain that it is disconnected at both ends before conducting any tests.

 

[Guest123]

All the control wiring should be tested as it is a fixed install that you have carried out. The OCPD for the system would be the BS 1362 3A fuse in the fused connection unit.

I usually carry out an R2 test for continuity of cpc rather than link out every item of control gear i.e timeclocks, valves, stats etc etc. I/R is carried out as described, all sensitive equipment removed/linked out or tested via method 2. EFLI & RCD carried out as usual if required.

 

[elementps]

Thanks Lenny, this is what I was planning on doing, just good to see someone else following same procedure.

 

[Gritishbasspark]

Be aware when doing a Zs at the boiler position that if you remove the cover of the boiler to test especily on new boilers they can incorporate a seal so removing it could be a risky buisness if your not able to get it back correctly and im pritty sure you need to be gas safe registered to remove them in any case (but dont quote me on that.) If you wanted to do it it with out removing the cover I find conecting the earth lead to the chassis of the boiler as this is exposed metal work and if the cpc gets to the boiler it should be conected to the chassis and give you your reading.

 

[oldtimer]

It would be advisable to learn how heating systems work and are controlled remember there is new digital room stats and all new boilers have electronic controls so a megger anywhere near this equipment is a no no.

 

[PC Electrics]

I test IR on CH systems at 250V and L&N to E only, usually from the wiring centre so all wires can be included.

As R1+R2 cannot be measured due to relays and switching components I test R2 only at all accessories.

NEVER attempt to measure Zs - you'll blow something up for sure.

Check all wiring visually against wiring diagram. Check all connections are sound. Remember it's I and T and CH systems rely heavily on the 'I' (especially for polarity, which like R1+R2 cannot be tested fully)

Test the system through all permutations of the functionality, making sure all items respond as they should.

Issue an MWC and notify (if you've added any new wiring or controls). Note testing lims on your cert.

 

[PC Electrics]

Be aware when doing a Zs at the boiler position that if you remove the cover of the boiler to test especily on new boilers they can incorporate a seal so removing it could be a risky buisness if your not able to get it back correctly and im pritty sure you need to be gas safe registered to remove them in any case (but dont quote me on that.) If you wanted to do it it with out removing the cover I find conecting the earth lead to the chassis of the boiler as this is exposed metal work and if the cpc gets to the boiler it should be conected to the chassis and give you your reading.

See post 8 for advice about never attempting to carry out a Zs test.

It is perfectly legitimate for an electrician to remove a boiler outer cover and any necessary inner covers to access electrical connections. Just don't attempt to remove or adjust any gas carrying components, except for their electrical function.

 

[Gritishbasspark]

I think you may have forgoten to read the part where i say but don't quote me on that. The point i was suggesting was that it was easyer to test with out removing the cover as long as there is an isolator near by to get your test probe on the line cable. In respect to doing a Zs on a boiler I do a Zs on every boiler I wire up and I do three or four a day and have never had a problem just for the love of god dont try and megger between line and neutral just as PC electrics said L&N to E write L to N as a limitation.

 

[wildgoose]

If I can't gaurantee what's connected to a circuit, then I only insulation test by connecting the Live & Neutral together and test with respect to Earth. Normally at 250v first then at 500v if confident there's no expensive electronics to screw up.


This L/N wrt Earth, technique is widely accepted now because of the vunerability of some electronics circuits at 500v.

ps: At 500vdc, watch out for that surge protection multiblock, usually for supplying IT equipt. They record low resistance values and cause lots of head scratching!!

 

[heating eningee]

Im sorry but this shouldn't be taking place how as a electrician can you test if the boiler is still room sealed after you have removed any casing?

 

[telectrix]

he's probably gassed everyone by now. thread is 19 months old.