Appliances Renovation

Misunderstandings about the safety aspects of cooking: Microwave ovens continue…

Checking power output

If a drop in power output is suspected, the following simple check can be carried out. You need paper and pencil, a spoon, two microwave-proof containers bigger than 500m1 (18fl oz) and a thermometer capable of readings between 10°C and 50°C. (The thermometer must not be used inside the microwave.) Unless seconds can be set on the oven itself, you will also require a stopwatch.

• Mark the containers A and B, fill each with 500m1 (18fl oz) water and stir. Measure and record the temperatures as T1 (temperature at start). Ideally, this should be about 15°C but not above 20°C, otherwise the results will not be accurate.
• Place the containers each side of the centre of the
  oven on the turntable if fitted, or on the base.

• Set the oven to its maximum setting (full power) and switch on.
• Allow the oven to operate for 87 seconds, then switch off.
• Remove the containers and stir well. Measure and record the temperatures as T2 (temperature after 87 seconds).
• Subtract T1 from T2 for each container. Calculate the average rise in temperature by adding the two answers together and then dividing by two. Multiply this average by 50 (this being the power supply cycle in the U.K. of 50Hz) to give the output of the magnetron in watts. Check the rating plate to confirm that it matches the manufacturer’s rating figure.

If results are found to be much lower than the nominal rating, this indicates a fault developing within the circuitry. Check that the oven is clean and dry and double-check all readings. If the reading is still low, have the microwave circuitry checked by a qualified engineer. To continue using the oven when a fault is suspected is false economy as further damage may result.

Use and care

Although you can do little to repair a faulty microwave oven yourself, there is a lot you can do in terms of correct use and care.

A microwave oven is much easier to clean than a conventional one, but even so, failure to do so is a common source of problems. A build-up of fats or sugars will absorb microwaves, heat up and burn. The carbon formed attracts even more microwave energy and the concentration of this energy can damage the interior of the oven and drastically shorten the working life of the magnetron, resulting in expensive parts replacement. Any spillages during cooking should always be mopped up immediately and thoroughly (some ovens have removable bases where liquids can seep into the cavity, causingsevere damage).

Regularly wipe the interior with a paper towel or slightly damp cloth. A little detergent may be needed on stubborn stains, marks or grease, but avoid abrasive cleaning liquids and scouring pads. Ensure the surfaces are clean and dry, paying particular attention to corners and grilles. To remove really stubborn stains, place a small microwave- proof container full of water in the centre of the oven and switch on to full power. Allow the water to boil for a short period of time. The steam will loosen the deposits so that they can be wiped away with a cloth.

Clean the outside of the oven with a damp cloth or sponge moistened with a little detergent. Do not allow any droplets to run into vents or panels. This applies also to the door inner and outer. Do not use wet cloths or aerosol sprays on the touch control pads of electronic ovens, as the liquid may seep into poorly sealed panels, causing damage or rendering the appliance temporarily inoperable.

Similar problems may arise if the microwave oven is sited in an unsuitable position, such as too close to an open cooking area, near a kettle or above normal oven vents. Steam might then seep between touch control membranes or condense as water droplets on components within the casing. This can cause low insulation or corrosion resulting in eventual failure. Often the first signs of this sort of problem are intermittent faults, such as being unable to set the oven or start it even though it worked when last used. After leaving it for a while and then resetting it, everything is seemingly working properly again. Watch out for this type of problem and try to prevent it by placing the oven in a more suitableposition.

DOs

• Do ensure that the oven has a good earth path, lead, plug and socket.
• Do check the cable for damage and avoid routing near hot or sharp areas.
• Do make sure that the oven is cleaned regularly.
• Do use the correct setting and times for the type of food being cooked.
• Do remember that standing time is important.
• Do have the appliance checked by a qualified microwave engineer if in any doubt.
• Do make sure that all parts are in place when using the oven, that is, all seals and panels, door correctly shut and seated correctly.

DON’Ts

• Do not allow the oven to operate when empty.
• Do not attempt to use a microwave oven if the door is damaged or hard to close, or the hinges are bent, broken or loose. Seek qualified help.
• Do not interfere with or poke items into the door latch holes. The interconnected switches and interlocks must not be tampered with.
• Do not use domestic ovens for commercial applications, such as in cafés or restaurants.
• Do not allow food particles or debris to build up within the oven cabinet, door seals or lip.
• Do not block air intake vents for the cooling fan
  or site the oven in damp or steamy conditions.

• Do not use metal containers, bag ties or skewers, porcelain with metal edging (painted or otherwise) or a complete wrapping of cooking foil (small pieces may sometimes be used).
• Do not remove the outer cover of a microwave .
• Do not use a microwave oven if the inner oven compartment is cracked or corroded in any way.

Possibly related posts: (automatically generated)
Misunderstandings about the safety aspects of cooking: Microwave ovens continue…

• Circuit for Electric Cookers continue...
• Misunderstandings about the safety aspects of cooking: Microwave ovens
• Circuit for Electric Cookers
• Using Basic Household Electronics Safety Hints (Cookers, Electric blanketsand Kettles)
• Saving Electricity
• Electrics Communications Hardware, Electric Bells, Buzzers and Chimes Wiring
• Using Basic Household Electronics Safety Hints (Wiring, Fire and Shock)
• Cut Electrical Bill on Heating and Cooking
• Using Basic Household Electronics Safety Hints (Bathrooms and Flexible Cords)
• Electric Water Heaters