Earth testing ect

[transam]

We have been having trouble recently with some boiler Pcb's on one particular make of boiler , alway's have suspected problem's with the house ( earth) wiring & have advised that customer get's a spark's in to test circuit's ect however

Someone from the CC suggested that it would be a good idea to invest in a Socket & see pdl 234 tester ?? any advise would this instrument test for a poor earth ect ect ??? or would you advise something else do not want to get involved in poking around inside consumer unit's or disconecting wire's in consumer unit's ect ect

 

[securespark]

You don't already have basic loop-testing equipment?


You also suggest you have been experiencing problems on more than one boiler.

Why do you suddenly think there's an earth fault affecting one of them?

 

[OwainDIYer]

It's not puttertan sopremos is it?

 

[transam]

You don't already have basic loop-testing equipment?


You also suggest you have been experiencing problems on more than one boiler.

Why do you suddenly think there's an earth fault affecting one of them?

Because it has gone through 4 pcb's each one lasted approx 7 day's , another fella on the CC has had the same problem same boier , a recent post on the heating forum is an exact same problem same boiler 3 pcb's each one lasting 7 day's !!

The pcb's show no sign of damage at all the problem occur's is that they will not tall the gas valve to open , they stick at sparking only change board evary thing is o.k for approx 7 day's , conclusion from every one so far is house electric's ??? Gloworm Ultimate , gloworm can offer no assistance / answer's

 

[transam]

Polarity is o.k voltage is o.k , can polarity change in a house from certain equipment use ?? my guess is no but ??

 

[ColJack]

oh sure, blame the house electrics.. it couldn't possibly be a FUBAR gas solenoid overloading the PCB could it??

have you tested the voltage at the property? maybe it's on the high side if it's close to the transformer..

 

[securespark]

Yes, it can. I went to a house where there was a boiler fault. RP. Then the guy went back and it was OK. Then the customer complained the boiler did not work again. The gas eng went back with a colleague and lo, it was OK again.

I went and found polarity OK, so got UU to check the incomer. All well. Then the boiler went RP again. When I went back, I found the whole installation appeared to be RP.

It was traced finally (though not by me) to a two-way lighting fault that caused apparent RP on the installation when the two-way switches were in a certain position.

Don't ask me how!!!!

Maybe a bear of greater brain than I can concoct a scenario where such a possibility could occur.

 

[ColJack]

it's AC.. there is no polarity..

ok so there's line and neutral "polarity" but that's not really polarity it just ensures that the switches / fuses are in the line conductor and not in the neutral.
as far as everything else is concerned, it changes "polarity" 50 times a second anyway..

 

[transam]

oh sure, blame the house electrics.. it couldn't possibly be a FUBAR gas solenoid overloading the PCB could it??

have you tested the voltage at the property? maybe it's on the high side if it's close to the transformer..

In all case's the gas valve has been changed , on our's the boiler had a new fan , all sensing lead's have been changed , Gloworm came up with the gas valve scenario knocking out the pcb's not the case as I see it it pretty much leave's the house electric's unless you have any other suggestion's ??? if the polarity change's at some stage it only effect's the boiler the house is brimming with computer equipment , but must than revert back again voltage is o.k in all case's (3) it has been suggested it is the earth ?? earth test's have been carried out with multimter on the appliance , boiler / control's are fed from a plug in socket , this was tested with a fluke socket tester tested o.k

 

[transam]

it's AC.. there is no polarity..

ok so there's line and neutral "polarity" but that's not really polarity it just ensures that the switches / fuses are in the line conductor and not in the neutral.
as far as everything else is concerned, it changes "polarity" 50 times a second anyway..

My definition wrong as it may be is the reversal of the live & neutral which would effect the ignition sequence ! this has not been witnessed in any of the case's

 

[securespark]

it's AC.. there is no polarity..

ok so there's line and neutral "polarity" but that's not really polarity it just ensures that the switches / fuses are in the line conductor and not in the neutral.
as far as everything else is concerned, it changes "polarity" 50 times a second anyway..

I appreciate what you're saying Col.

But I was meaning RP as in L & N crossed over. I know the fault I looked at could not have physically reversed polarity, but I think the fault caused the boiler to perceive polarity as having been reversed. How, I'm not sure....

 

[transam]

Interesting securespark , don't suppose you would have any objection if I put your post on the CC would you ? you might be the !st sparky to get a post in there

 

[securespark]

Nope. Give me a few ticks and I'll see if I can locate my original post from the time.

 

[securespark]

Here it is:

//www.diynot.com/forums/viewtopic.php?p=469282

 

[ColJack]

given that you can switch the boiler on at any point during the cycle, I don't see how it ( the boiler ) can check for polarity or that a change in polarity ( L-N reversal ) would affect the boiler at all..

the ONLY thing I can see is that the gas valve ( new or not, might be too big ) is causing arcing and / or back EMF to whatever controls it ( don't know if it's solid state relay of semiconductor controll.. )

if there are voltage spikes then that might nerf something on the PCB, a transistor or maybe even a surge protector.. )

as it fails to open the gas valve then It might be a wiring fault within the unit itself, maybe a damaged wire etc, though the general timeline of about a week seems to rule this out as it would be more random than that.. .

if there is a dodgy earth to the appliance then any kind of internal surge protection / filtering of the supply would not work properly as they generally dump the surges / filtered noise to earth to get rid of it.. so they might be right..

of course it could just be that there's a bad batch of PCB's with a faulty component that might not work with older kit and that gloworm just doesn't want to admit that and recall hundreds of PCB's for a few that might be incompatible..
maybe they tightened the spec on one or 2 components to make it cheaper ( like using 5A relays instead of 10A etc.. )..
with the older gas valves they don't work ( and the original fault WAS caused by a dodgy valve but the replacement is the same size etc.. )