Immersion heater cutouts Ask questions and find answers to many subjects relating to electrics and electrical work

[incognito]

Hi All,
Can someone tell me how immersion heater cutouts work and how they can be reset? Also can anyone tell me how to change an immersion heater without the water spilling out of the top of the copper hot water tank?
Mike

[BLAKEY1963]

[quote="incognito"]Hi All,
Can someone tell me how immersion heater cutouts work and how they can be reset? Also can anyone tell me how to change an immersion heater without the water spilling out of the top of the copper hot water tank?
Mike[/quote]

MIKE
The cut out as u call it , is a thermostat , normally 16 - 20 inches long
maybe more, depending on size of element.
they work on temperature setting ,( manually set ) .
WITH POWER OFF , SUPPLY ISOLATED ! , AN low resistance
omhmeter cab be used , across the thermostat to detect a deflection of the meter or a reading to indicate , it is working .
As for draining your immersion tank , have u tried the plumbing
DIY DOCTOR FORUM.
POST YOUR query onto plumbing and i am sure expert advice
will be given .
BLAKEY1963

[sparx]

Hi mike,
not all immersion heaters have an overtemp. cut out built into thermostat, only been in common use for a few years.
If fitted usually look like a small dot or small pin, which needs pushing in with pointed implement until it clicks.
To change element means turning off water inlet to tank, then whilst tank still full of water turn out large boss 1/2 turn with special ring spanner sold for purpose, then draw of some hot water from a tap, to lower level below element. Then undo element & replace, doing reverse .
OR better still call a PLUMBER to do it as it's very easy to tear cylinder away from boss.

[kuzz]

Like sparx says "crack" the element first with the tank still full or there is every chance it will twist or buckle. personally i find this much easier with a box spanner, the ring type are awful. you probably will have to hit the bar of the box spanner with a reasonable amount of force. DO NOT just run the hot water as when it stops running only the header tank is empty. The tank must be drained down using the drain off or my preferred method (combination cylinder type) is syphoning. (Thin hose pipe down the pipe that takes cold water from the header tank to the bottom of the cylinder, suck to start then let gravity do the work. A mouthful of water is worth avoiding though.)