Testing Immersion Heaters and Thermostat

Oct 12, 2006 5 Replies
S

Re my previous post about my Immersion heater failing to heat and my getting the wrong item from

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they have now replaced letting me keep the "wrong" item . I replaced the thermostat from it in to the exisiting immerser which I thought was the problem but still the water didn't heat so I have just installed the replacement immerser I got today and it appears to be working fine .. . I now have the old immersion heater sans thermostat which I binned .I also have the other immerser with thermostat .



Is there a way of testing immersers/thermostats other than fiting them and seeing if they work ( if they do not you still have the problem of knowing if it is the thermo or the heater that is faulty)



Someone mentioned using a multimeter but can someone explain exactly how you do that please .I'd like to know out of interest if for no other reason . thx Stuart


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M

Immersion heater: test resistance between the 2 mains Terminals, and from terminals to Casing. T-C should be open circuit, any significant conductoin and its liable to blow fuses or rcd. T-T should be 20 ohms for a 3kW element, higher for lower power elements. If R is much higher its faulty.

Thermostat: the 2 terminals should be shorted at room temp, and should go open when probe stuck into boiling water.

NT

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M

Immersion heater: test resistance between the 2 mains Terminals, and from terminals to Casing. T-C should be open circuit, any significant conductoin and its liable to blow fuses or rcd. T-T should be 20 ohms for a 3kW element, higher for lower power elements. If R is much higher its faulty.

Thermostat: the 2 terminals should be shorted at room temp, and should go open when probe stuck into boiling water.

NT

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S

Thx NT ...I've now got myself a DMM and will check them to see if they are working .I've been meaning to get a DMM for a while anyway.I'm sure it will come in useful .

Stuart m

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T

My daughter (totally untrained electrically speaking) fixed her immersion heater by finding and pressing an internal reset button.

Probably not inherited DIY knowledge but deeply ingrained reluctance to pay for expert help:-)

regards

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S

Yes.Modern thermostats do have a cutout button on top which protrudes when activated . It is a very small button if you are looking for it .

Stuart

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