Kettles, electric urns and rice boilers

This page covers electric kettles and urns, and may contain some useful tips concerning rice boilers.

Summary

Electric kettles and urns are basically fairly simple devices but the combination of heat, water and electricity can often lead to failures. This is particularly true of cheap electric kettles which often, unfortunately, can't be repaired.

Safety

Always double check that the device is unplugged before starting work. It could be very dangerous to test it by plugging it in whilst partially dismantled.

Parts may be very hot after the device has been switched on. Be sure to allow them to cool before working on it.

Electric kettles

We frequently see broken electric kettles at Restart parties but unfortunately tend to have limited success in repairing them. Most modern ones are cordless, resting on a circular base which is connected to the mains supply. Some older cordless ones have a non-circular base with the connections beneath the handle. Even older ones have a detachable lead and these have an element that you can see when you look in the top, and might even be replaceable. More modern kettles, on the other hand, have the element built into the metal bottom of the jug. They all work by providing a path for the steam, as they come to the boil, over a bimetallic strip which bends under the heat, so flicking off the switch.

If the kettle is completely dead, check the fuse before doing anything else. This is not often the problem but is easily checked and could save you a lot of time. Again, not often the problem, but you might also like to check the connections fro the mains plug through to the base.

Sometimes the problem is a lid which doesn't close or stay closed, and this can be a broken piece of plastic, not often repairable. There may be some screws under the lid allowing you to access the hinge or catch.

Disassembly usually starts with removal of several screws in the base. Some or all of these may be security screws to prevent unskilled tampering. The base will then come off allowing you to examine the switch, the element and any other parts.

The element is probably the first thing to check. The connections should be fairly obvious and you can check it with a multimeter on a resistance range. For a 3KW kettle it should read around 20Ω. The element is not usually replaceable.

There is likely to be a thermal fuse to cut off the current in the event of the kettle boiling dry or being operated empty. Test it with a multimeter on a resistance range (it should record practically zero resistance). This, you may be able to replace, but make sure the replacement is rated at the same temperature and current. It may be mounted so as to be in good thermal contact with the base of the jug, and a replacement must be mounted likewise.

The switch mechanism consists of several plastic and metal parts allowing it to be switched on by an external control and switched off by the bimetallic strip. The plastic parts sometimes get broken, and here too, they are not often fixable. Sometimes something may get dislodged and you might be able to see how to fix it.

Water leaks are sometimes a problem, and these are hard to fix, particularly in the presence of limescale. Steam may get into the switch mechanism and causes corrosion. This too is problematical but there may be some hope if you can clean it up.

Electric urns

Catering urns, particularly the higher quality ones, may offer more hope as spare parts may be available and may not be hard to fit. Spare elements, switches, thermal cut-outs, taps and other parts may be available from a catering equipment supplier.

Fault finding initially follows the same principles as for a domestic kettle. Instead of a thermal fuse it may have a thermal cut-out with a manual or automatic reset. The manual reset types have a button to press which will give a definite click as it resets, but some level of disassembly is likely to be necessary to access it as the button will be very close to live contacts.

Automatic fill types of urn are designed to be plumbed in to a water supply and contain an electrically actuated stop cock. There will be sensors to detect the water level and temperature, feeding into some sort of controller which switches the element and operates the stop cock.