Stephen wrote:
Hope someone can advise.

The fuse on my immersion heater keeps blowing. It is on its own 15A
circuit. The fuse doesn't blow immediately but after one or two
days.
I have replaced the fuse three times and wired around the timer to
eliminate it as the cause.

Could it be anything other than the immersion heater causing the
blown
fuse ?

The hot water is only heated by the immersion as there is no gas and
the unit is around 12 years old. The make is a Thermtec Ltd 3kw.

If I need to replace the heater, do I need to buy a new thermostat
or
can I re-use the old one ?

Thanks in advance.

given the age, just get another immersion, these come with a new
thermostat and only cost a few pounds.

MrCheerful

BillR wrote:
MrCheerful wrote:
Stephen wrote:
Hope someone can advise.

The fuse on my immersion heater keeps blowing. It is on its own
15A
circuit. The fuse doesn't blow immediately but after one or two
days. I have replaced the fuse three times and wired around the
timer to eliminate it as the cause.

Could it be anything other than the immersion heater causing the
blown fuse ?

The hot water is only heated by the immersion as there is no gas
and
the unit is around 12 years old. The make is a Thermtec Ltd 3kw.

If I need to replace the heater, do I need to buy a new thermostat
or can I re-use the old one ?

Thanks in advance.

given the age, just get another immersion, these come with a new
thermostat and only cost a few pounds.

MrCheerful

But it can be very hard to get the old one out esp. in hard water
areas. Often resulting in buckled cylinder if you're not careful.

Then to prove that the immersion is faulty, rewire it from a plug and
see if that blows the fuse too. The thermostat will not cause fuse
blowing in my experience, while the element will.


I have changed lots of elements over many years and only once has the
cylinder started to twist and buckle because of tightness, although
the element still undid ok and a new one went in ok. Always start the
undoing process with the cylinder full, even if the element is at the
bottom, the weight of water keeps everything stable, also use a socket
with crossbar if possible.
MrCheerful

In article ,
(Stephen) writes:
Hope someone can advise.

The fuse on my immersion heater keeps blowing. It is on its own 15A
circuit. The fuse doesn't blow immediately but after one or two days.
I have replaced the fuse three times and wired around the timer to
eliminate it as the cause.

Could it be anything other than the immersion heater causing the blown
fuse ?

The element could have shorted to the casing, causing it to draw
more current. This will make the fuse carrier very hot (and the
cable quite likely warm too).
If it's an intermittent short such as a cable fault, then the
fuse carrier won't have time to heat up (although it might be
slightly warm just from normal operation of the immersion heater).

This is a handy technique to diagnose an overload current blowing
a fuse verses a fault current (short circuit) blowing a fuse,
but you have to get there immediately after it happens.

--
Andrew Gabriel

"MrCheerful" wrote in message
...
BillR wrote:
MrCheerful wrote:
Stephen wrote:
Hope someone can advise.

The fuse on my immersion heater keeps blowing. It is on its own
15A
circuit. The fuse doesn't blow immediately but after one or two
days. I have replaced the fuse three times and wired around the
timer to eliminate it as the cause.

Could it be anything other than the immersion heater causing the
blown fuse ?

The hot water is only heated by the immersion as there is no gas
and
the unit is around 12 years old. The make is a Thermtec Ltd 3kw.

If I need to replace the heater, do I need to buy a new thermostat
or can I re-use the old one ?

Thanks in advance.

given the age, just get another immersion, these come with a new
thermostat and only cost a few pounds.

MrCheerful

But it can be very hard to get the old one out esp. in hard water
areas. Often resulting in buckled cylinder if you're not careful.

Then to prove that the immersion is faulty, rewire it from a plug and
see if that blows the fuse too. The thermostat will not cause fuse
blowing in my experience, while the element will.


I have changed lots of elements over many years and only once has the
cylinder started to twist and buckle because of tightness, although
the element still undid ok and a new one went in ok. Always start the
undoing process with the cylinder full, even if the element is at the
bottom, the weight of water keeps everything stable, also use a socket
with crossbar if possible.

When removing an immersion element from a cylinder, always heat the copper
around the immersion with a blowlamp. This expands the copper and makes it
easier to screw out.


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