Is there a standardized method for testing a microwave oven for proper function?
Or what do you do to ensure unit is functioning properly?

The reason I ask is AHS is refusing another clients request for repairs.

__________________
badair http://www.adairinspection.com Garland, TX 75042
Residential-Commercial-Construction-EIFS-Infrared Thermography
life is the random lottery of events followed by numerous narrow escapes

Barry,

If and only if it's a built in.

Crumpled up Wet paper towel. Starts to steam in about 30 to 45 seconds on high.

__________________
It Might have Choked Artie But it ain't gone'a choke Stymie!
Billy J. Stephens HI Service
Memphis TN.

Barry,

I follow what I learned from a 20+ HI veteran in Houston:

Timer & Clock: Functioning? Y/N (actually an additional item not required)
MWave: Small glass of water, heat/run for 60 seconds, if water is boiling it is functional.
Carousel: Turns? Y/N

Then there are the Range Hood options, but that is a different section of the 7A-0 form, but I do refer one to the other.

As noted above ... for built-in units only. I don't touch the portable units.

__________________
Cheers - Nolan E. Kienitz, PMP
Dallas Home Inspector
www.NolansInspections.com

Barry, I don't know of a specific test, but the boiling water is mentioned in the TREC standards as an option.

My other test equipment is the multipurpose rag I carry in my pocket which exhibits an elevated temperature when heated for 10 seconds. My test equipment is faster and safer and can be used even if no water service is present. I tried using the boiling water thing when I first started out and got burned once.

__________________
Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002

I carried a microwaveable hard plastic drinking cup which I would fill with water, set the timer to 30 seconds, and if the water was not 'hot to the touch', it was 'not working'. Depending on how large or small a cup you use, the water will likely boil in less than 60 seconds - I found that with the size cup I used, 30 seconds would make it 'hot to the touch'.

__________________
Jerry Peck, Construction / Litigation Consultant
Ormond Beach, Florida
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

I've always said a cup of tap water for 1 minute at high should be at least 120°F otherwise just wait for the sink supply in most homes.

I also carry microwave popcorn and will pop a bag for function and snacking on vacant properties and will ask permission on occupied, when clients are around, they like the treat and proof their future micro is working.

The issue on this one instance is a $900.00 unit that requires repair or replacement IMO and the warranty co. does not want to honor their agreement, go figure.

I was just curious what test methods were used by others.

Warranty co. says, "Inspector's 1 minute test along with a light tester is inferior and should be tested on high for 2 1/2 minutes this should boil water 212°F in most units."
Unit in question will only get to 200°F by their own time and test,
"but that is close enough" they say.

Glad I don't have to eat their cooking

Found this wattage formula but doubt it's any better than what I/we try to do during an inspection How to Easily Test Your Microwave Oven's Wattage

I'm with Jim on the boiling thing, injury or too messy on previous occasions

I'll be sticking to the 1 minute and light tester or popcorn until shown different

HNY BTW and thanks for your replies

__________________
badair http://www.adairinspection.com Garland, TX 75042
Residential-Commercial-Construction-EIFS-Infrared Thermography
life is the random lottery of events followed by numerous narrow escapes

Barry,

I also do the test with a cup. I use the regulation sized sippy cup, nothing fancy.

Fill the small cup and turn on for 1 minute. If water is hot to touch, I note on report that a cup of water was heated after 1 minute test.

I also check to make sure the turntable is operable and that the unit is properly supported. Check to make sure there is no damages to the door or the glass panel.

Another thing I do is make sure that the recirculating fan is venting properly. Many of these have had to fan cover panel removed as if they are going to be vented to the exterior; but many I have found vent to the bottom of the above cabinet.

I also make note if the bottom surface light is not operable and the condition of the filters.

rick

I guess it goes without saying to check the receptacle the microwave is plugged into - I have found quite a few that are improperly wired, when the rest of the receptacles in the kitchen were ok.

I use the wet paper towel method. Wet the paper towel put it in the center and turn the unit on for about 15 seconds. That is all it takes for a nice steaming paper towel.

In my report I tell how I tested the microwave and that the only thing I can tell them is that it worked well enough to make the paper towel steam. I write in the report that I did not cook anything in it to test it.

__________________
Scott Patterson
Spring Hill, TN
http://www.traceinspections.com

Their 'standard' is likely for their 'new' units. That may be how they selectively test their units heating capability off the assembly line. Not real scientific like the QA tests I did at a defense plant I worked at for 5 years after high school, but, then, this is not trying to guide airplanes at 500 mph at 50 above the ground either . Their test will demonstrate that the 'unit is working to their specification', presuming that is representative of their specification, of course.

Now, to the link you provided:
"Keep in mind that it’s normal for a microwave to produce less energy as it ages (hmmm… sounds familiar somehow!), but your results should be within about 50-75 watts of the rating."

I'd guess that the 12 degrees difference is within or close to that "50-75 watts of the rating".

By the way, the stuff I worked on was with microwaves, only very few of our tubes were in that low wattage range. We even had a few in the <1 watt (rated in mW) range, but most were in the kW to MW range (some I tested were over 5 mega watts). Nonetheless, though, there is a reduction in power over time (aging effect) as stated in your link.

__________________
Jerry Peck, Construction / Litigation Consultant
Ormond Beach, Florida
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

Notice there is no reference to the starting temperature?
That would also be something to consider when testing to a specific temperature over a certain time; 40 degree water takes longer to reach boiling than 80 degree water.

__________________
Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002

Does, did or will the warranty company provide documentation for their testing procedures? It would be nice to see what that basis is.

I don't think any of the various SOPs get to this level of data collection for a microwave.

I know that isn't the bottom line here as you are working with a client to help resolve an issue and are being taken to task for more definitive information.

__________________
Cheers - Nolan E. Kienitz, PMP
Dallas Home Inspector
www.NolansInspections.com

I basically do all the same as stated above:

check seal
turntable
light
temp w/ sippy cup of agui for 1x min-- s/b 110-120F
CHECK FOR RUST!!! Any rust is necessitates hitting it with a baseball bat.

I do not check units not permanent to the structure (built-in).

Dick

__________________
"If con is the opposite of pro, is Congress the opposite of progress?"
Richard Rushing, HCRI
Duncanville, Tx.

I use the paper towel method too.

NOTE!! Do NOT put a "dry" fabric shop towel in for the test. It WILL catch fire - yes flames and a lot of nasty smelling smoke. Not that it ever happened to me....no, and that's my story.

I check the control panel to see if the buttons work.
The light and turntable.
If it heats up my paper towel to steam.

"Inspector's 1 minute test along with a light tester is inferior and should be tested on high for 2 1/2 minutes this should boil water 212°F in most units."
Unit in question will only get to 200°F by their own time and test,
"but that is close enough" they say."

They may have a point. The cheapo microwave in my basement takes much longer to make popcorn compared to the one in the kitchen. I think the power rating has a lot to do with it. If it boils water in a reasonable amount of time, I would have to say it is probably OK.

When I make press coffee (in the good kitchen one), I put 16 oz of water (room temp) and hit 3 minutes and it boils just before the timer goes off. And it's a full rolling boil by then (220 degrees).

I have found that if I use the water from my refrigerator door, it just about the same time.
JF

Why any paper towel at all? Why put anything combustible at all in a micowave? Show me the light.

rick

Rick,


It's wet not damp. Most always on site. one less thing in the bag.

Push 33 start it steams that part of testing is done.(Don't Walk away).

1.Dish Washer

2.Set Oven 350

3. Set Burners on Low

Snatch a couple of paper towels (wet and leave water running.)

Press 33 start.(Light comes on?,Table turning?

Open cabinet under sink (Drain Leaking?)

Microwave timer dings. Steam = Microwave,Seal?Cabinet?Test other Buttons,

Back to Drain. ect.

Everybody has their own way.

__________________
It Might have Choked Artie But it ain't gone'a choke Stymie!
Billy J. Stephens HI Service
Memphis TN.

220 degrees F?

I've always thought, and been told, that water boils at 212 degrees, and that boiling water never gets hotter than 212 degrees F - it just boils faster and faster and faster the more heat you add, but the temperature does not rise.

__________________
Jerry Peck, Construction / Litigation Consultant
Ormond Beach, Florida
Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )

Generally speaking: the temperature at which boiling occurs (boiling point) depends upon pressure. At sea level (14.7 psia or 0 psig), yes water boils at 212 degrees. On a mountain in Colorado it will boil at a lower temperature. A lot of cook books have "high altitude" instructions to adjust recipes for this lower boiling temperature. Water will boil at higher temperatures when under pressure (hence the use of the "pressure cooker") and on a submarine (I believe they do allow the air pressure to increase somewhat above normal atmospheric when submerged).

When it begins boiling, liquid water will continue to boil at the same temperature (dictated by the pressure). As more heat is applied the rate of boiling increases but the temperature remains the same. The steam will be at a much higher temperature than the boiling water.

However there is also a special case called superheating. A liquid can be heated to a temperature significantly above it's normal boiling point if it is heated in a smooth walled container and kept very still. This prevents those little bubbles from forming in the water (called nucleation) and delays the onset of boiling. When being superheated, the water is storing energy that will be released in a steam explosion accompanied with rapid boiling if the water is disturbed.

Superheating is a concern when using microwave ovens to boil water, especially those units without turntables. Opening the door, setting the cup down on the counter, dropping a tea bag or a spoon of sugar into it ... any of these could kick off the boiling process and send scalding water flying. Many people have gotten severe burns from this.