Economy Seven timer (horstmann)

wazzer1

Hi folks, the above timer was tripping the RCD in a friends apartment, everytime he went to switch it on. Had a look for him and after checking the resistance on the elements (which was fine) opened up the timer. Everything seemed visibly fine inside, and when i bypassed the timer, the RCD no longer tripped...The timer is only two years old, and since ive never worked with them before, im wondering should they go after this length of time?? As their fairly pricey to replace..

Thanks in Advance.

M cebee

wazzer1 wrote: »

Hi folks, the above timer was tripping the RCD in a friends apartment, everytime he went to switch it on. Had a look for him and after checking the resistance on the elements (which was fine) opened up the timer. Everything seemed visibly fine inside, and when i bypassed the timer, the RCD no longer tripped...The timer is only two years old, and since ive never worked with them before, im wondering should they go after this length of time?? As their fairly pricey to replace..

Thanks in Advance.

sounds unlikely ime
did you megger the immersion

meercat

M cebee wrote: »

sounds unlikely ime
did you megger the immersion

agree with m cebee here
most likely immersion element

wazzer1

Just got resistance off immersion, and the readings seemed about right. Would it not be strange for immersion elements to wear so quickly. Maybe not if its a hard water area i suppose. Any other way to check without putting a meggar on it?

Thanks.

M cebee

not really

you can pick up a cheap megger for troubleshooting-doesn't even need to be calibrated

meercat

megger is best

i assume its the boost(top element)if there are 2 side elements

disconnect it at the element and place wires in connector block
then switch it on
check for voltage
if it doesnt trip,then its most likely a faulty element

when element is disconnected check resistance across element terminals and earth on cylinder(this may show up an earth fault)

wazzer1

Ok suppose thats the only option then. Dont want him havin to buy a new timer if its not that at all!! I thought checking the resistance across L/N would tell ya the condition of the element, but obviously not. If it was the element gone on the top tank tank which is used for the boost,wouldit still trip straight away or only when you try use the boost function??

meercat

wazzer1 wrote: »

Ok suppose thats the only option then. Dont want him havin to buy a new timer if its not that at all!! I thought checking the resistance across L/N would tell ya the condition of the element, but obviously not. If it was the element gone on the top tank tank which is used for the boost,wouldit still trip straight away or only when you try use the boost function??

i would say that the boost function is double poled so there would only be a neutral-earth fault when its switched on

Bruthal

wazzer1 wrote: »

I thought checking the resistance across L/N would tell ya the condition of the element, but obviously not.

The immersion heating wire inside the element can still be intact, but the casing of the element splits, tripping the RCD, but still giving the proper reading on an ohm meter. Years ago before RCD`s were on immersions, they would be continued to be used after the element casing has split as there would be no indication of the fault, and the element would sizzle away and eventually would stop heating the water properly. By this time they were often in tatters when removed.

An earth fault should show up on a multi meter by testing from both ends of the immersion element to earth, with the multimeter setting on a high ohms setting.

A meggar is better as the lads said, but the multimeter should show it.

wazzer1

Cheers lads, all sorted, it was the off-peak element.

meercat

wazzer1 wrote: »

Cheers lads, all sorted, it was the off-peak element.