Immersion stat

[GrahamT]

Any ideas why an resetable immersion overheat stat would keep tripping?

I've tried 2 new ones and all have overheated as oppose to just turning on & off

 

[kevplumb]

Any ideas why an resetable immersion overheat stat would keep tripping?

I've tried 2 new ones and all have overheated as oppose to just turning on & off

short answer is its overheating

try checking the adjustable stat

 

[GrahamT]

so why hasn't the adjustable stat prevented this on all 3 stats that have been fitted?

 

[kevplumb]

err cos its not working would be my first guess

 

[Gasop]

Make sure that the connections are as tight as possible.
Loose terminals can cause extra heat.

If you bought the Immersion from PTS then dump it and get another elsewhere.

 

[GrahamT]

err cos its not working would be my first guess

so the original and 2 new stats are all faulty??

Any "help" rather than short smug statements would be much appreciated.

Further to my original post, the immersion as a whole is new (from Plumbase), the stat kept overheating - I then replaced with new stat from Grahams - this overheated - have just put another new one from Plumbase in today.

I also know the timer is faulty and constantly on. This is to be replaced, but I thought the stat would just keep turning on/off as the water is used and cooled etc.. Unless it is getting overworked?

 

[JohnD]

what temperature is the hot water, what is the element stat set to, is the cylinder also heated by a boiler, does the cap on the immersion feel unusually hot?

 

[cider]

Often overheat of immersion is caused by the primary heat source heating the water hotter then the oh stat is set to.
For example if the cylinder is connected to a rayburn.
If this is the case just bypass the oh stat

 

[kevplumb]

Further to my original post, the immersion as a whole is new

then why didn't you say so

 

[GrahamT]

it's a direct cylinder and the stats were set at 60 C

 

[picasso]

Often overheat of immersion is caused by the primary heat source heating the water hotter then the oh stat is set to.
For example if the cylinder is connected to a rayburn.
If this is the case just bypass the oh stat

not a good idea, when the boiler isint being used(for whatever reason) the immersion will be switched on with the o/h stat bypassed.

 

[cider]

like they have for the last 50yrs before some jobsworth made them over safe

 

[TicklyT]

Just checking - is it actually overheating, or is the overheat cutout tripping at a lower temperature than it should?

Is it wired correctly?

Some immersions have nice big terminal posts on the heater element and cutout, but hide the small terminal on the side of the thermostat the live feed should connect to.

A wiring fault could have been there since the original installation was made. It could be masked by the timer switching off the supply before it overheats, the problem only coming to light when the timer fails.