Immersion heater fault

[TPES]

I have a customer who had a fault on there immersion, they've lived with this fault for about 8 months and just relying on the boost to give them a quick short supply of hot water. They said it used to work fine, no problems then just went off,

So after going and having a look it was just there thermostat had tripped out and wanted re-setting, so i did this and turned the temperature down slightly, the next day the customer text me saying everything was lovely and they had plenty of hot water. Sorted!!.... So I thought..

After a couple of days she says there is no hot water again... So going back I did IR tests across the element showing no open circuit, and knowing that the element was fine just a couple of days ago i was assuming my fault would be the thermostat again, continuity across the stat when turned up and down just as I would expect..

So I rang "santon" as it is a santon premier plus cylinder. They said they have replaced the original stats that came with the premier plus for a new design of stat, I explained my customers problem to them and they said I was right to change for one of there new immersion stats 11" long.

The stat got delivered and I put it in last night, this morning the customer text saying..."sorry, but still no how water" when they woke up

Without changing the element is there anything you chaps could recommend? And when testing heat elements what figures are you expecting on your meter be it an immersion or storage heater element?

I know a simple continuity test end to end Of the element isn't always accurate as you can still get it to bell out but have a faulty element, so IR test are more accurate..

 

[Deleted member 19807]

is it on any sort of timmer? I have replaced 2 timmers in the last month both the same make (from screwfix)

on one system the over temp button had poped out, this we found was caused by the heating system thermostat not working and taking the water temp over the safety limit for the thermostat so when they tried the immersion it would not work.

you could bypass the thermostat to test the element directly, you should hear it heating within a few seconds.

I suspect you will find the answer when you go back, just start with the basics,

you will probably find the user has not got it turned on.

 

[Deleted member 9648]

You would expect a resistance through the element of 17-18 ohms...(simple ohms law...a 3000w element on a 230v supply)..If the IR to earth is OK and you get that sort of continuity figure the element is fine...there have been lots of problems with overheat cutouts on some stats...I've been back to a few. If the cutout keeps operating for no apparent reason get back on to santon for advise.

 

[TPES]

It is economy 7, on late at night, She's never touched anything, the isolator is on just as it has always been and it was working for a couple days with no problems.

 

[truckster]

These poxy high limit stats are causing a lot of problems judging by the amount of posts around the forums, it seems to be pot luck if you get one that is actually calibrated right.