Testing new Microwave

jollyanna

I have a new 900 wat combination microwave oven and I'm unsure if it is functioning at the correct level. My last one was an 800 wat panny and this new one should obviously be more powerful but I'm constantly having to do extra mins and secs to get the desired heat from what I'm cooking/heating. Are there any tests I can run myself before going back to the retailer saying I suspect it doesn't function as it should ?

RussellS_2

You can test it by heating 1L of water for a set time and then checking the temperature of the water.

1. Procedure Using Fahrenheit Thermometer:
2. Pour exactly 1000 milliliters (mL) of cool tap water into a microwave-safe container. Using the thermometer, stir the water for about 10 seconds, then measure and record the temperature. For accurate results the initial water temperature should be between 60 degrees F (15.6 degrees C) and 80 degrees F (26.7 C).
3. Place the container on the center of the oven cooking shelf. DO NOT leave the thermometer in the container. The cooking shelf (tray) or turntable must be in place and any metal racks must be removed.
4. Heat the water for 33 seconds at full power. Use an accurate digital timer or stop watch if the oven has a mechanical timer.
5. After the heating time is completed, immediately remove the container, stir the water for about 10 seconds, re-measure and record the temperature of the heated water.
6. Subtract the starting water temperature (step 1) from the ending water temperature (step 4) to obtain the temperature rise.
7. To determine the output power in watts, multiply the total temperature rise by a factor of 100.
8. Example:
   1. Starting temperature (T1) = 60 deg F
   2. Ending temperature (T2) = 72 deg F
   3. Subtract T1 from T2: 72 - 60 = 12 (temperature rise)
   4. Multiply temperature rise by 100: 12 x 100 = 1200 watts
9. The test may be repeated to insure accuracy

Procedure Using Centigrade Thermometer:

1. Same as above
2. Same as above
3. Heat the water for exactly 62 seconds at full power. Use an accurate digital timer or stop watch if the oven has a mechanical timer.
4. After the heating time is completed, immediately remove the container, stir the water for about 10 seconds, re-measure and record the temperature of the heated water.
5. Subtract the starting water temperature (step 1) from the ending water temperature (step 4) to obtain the temperature rise.
6. To determine the output power in watts, multiply the total temperature rise by a factor of 70.
7. Example:
   1. Starting temperature (T1) = 16.0 deg C
   2. Ending temperature (T2) = 33.0 deg C
   3. Subtract T1 from T2: 33.0 - 16.0 = 17 (temperature rise)
   4. Multiply temperature rise by 70: 17 x 70 = 1190 watts
8. The test may be repeated to insure accuracy

Just make sure you use a 100% microwave safe container as you want the microwave energy to go into heating the water and not the container.

jollyanna

Thank you Russels, how did you know that ? I'm off to seek out a thermometer - only one I have is a digital poorly person type so I may have to buy a new one.
I've tried looking for reviews of this micro (Prestige ) but not found a single one. Sometimes when you read if another consumer has had doubts about performance it makes you think, aha, it's not my imagination. I hope it will be OK as I spent ages looking and this one suits my needs perfectly.

RussellS_2

I used this method a few years ago when our old microwave seemed to be taking longer and longer to heat things up. I couldn't remember the procedure exactly so I did a google search for it. I would have posted a link to the article but I wasn't allowed to as new members can't post links in this forum to stop spamming.

Anyway, glad to have helped.

totalsolutions

Watt you have will be OK, measuring say 33.0 deg C. Just don't leave it in the water container whilst you heat it up.

jollyanna

I'll be doing the test tomorrow. Is the retailer likely to take my word for it if I suggest it could not be functioning properly ?
Does anyone know who makes Prestige microwaves ? So many maufacturers seem to be umberellas for different labels and you don't quite know who's made it.

ih8stress

jollyanna wrote: »

I have a new 900 wat combination microwave oven and I'm unsure if it is functioning at the correct level. My last one was an 800 wat panny and this new one should obviously be more powerful but I'm constantly having to do extra mins and secs to get the desired heat from what I'm cooking/heating. Are there any tests I can run myself before going back to the retailer saying I suspect it doesn't function as it should ?

I've recently got a new microwave and been experiencing the same problem.

Does anyone know if it is possible to adapt the test (or use another method entirely) as

a) my microwave pan only holds half a litre of water
b) I've only got a meat thermometer in the house

I've done a rough test using half a litre of water in a plastic microwave pan for 62 seconds at full power (not sure if I should have reduced the time as well).

Before temp: 10
After temp: 24

= 14, 14 x 70, = 980 watts.

The microwave is a 700 watt model.

Does this sound about right?


Also, if the Op is reading this, how did you get on with the test, and did you end up returning it?

Thanks:)

jollyanna

Hi, yes I did try the test and result was a bit wonky/ not finite, which I attribute to using a digital medical thermometer. I've been too busy with kitchen re-fit and Xmas stuff to look in to it further but I am planning to in the New Year. Mines a combination convection and I'm now not convinced the convection oven is performing as it should either ! I need to cook in it a bit more before I start making complaints so at least I will have given it sufficient time to get to grips with it and be certain that it ain't right before steeling myself to confront the retailer. Good luck with yours.

ih8stress

Thanks for the reply jollyanna. Mine is a cheapo Tesco value one, which I got in the recent double-up scheme. I think I have 28 days (nearly up) to return for a refund/exchange. Otherwise you get into the whole return for repair scenario.

Like you, I'm not sure what the tests revealed exactly. Yours sounds more complicated being a combination one but I would say if in doubt, get in touch with them.

My problem is getting back to the store (no transport) and no doubt just getting half the value back.

Good luck. Enjoy your Christmas.