Question about OTR microwave design...

[superocd]

Does the vent fan double as the cooling fan for the transformer/magnetron? I've noticed with every OTR microwave I've used, the vent fan seems to kick on when the microwave itself is used, which leads me to believe that there isn't a separate cooling fan for the microwave components like there is with standard countertop microwave.

Does anyone know whether this is true or not? This has me curious, lol.

 

[arbilab]

In a 1990 apartment, the OTR hood fan was separate from the magnetron fan in both a GE and a Whirlpool.  (Incidentally, both electronics failed while my 1982 GE still works fine today.)

 

In today's world of mindless costcutting, wouldn't surprise me to find only one fan.  Though sucking grease-laden hood air over the mag'tron sounds like a bad idea, may not make much difference in a product designed to fail when the warranty runs out.

 

[yogitunes]

best way to find out is to open it up and have a look see.....

 

[tomturbomatic]

I should think that you would be able to tell from the noise level between just zapping something versus running the exhaust fan alone. I can't imagine that running the noisy exhaust fan every time you ran the microwave would make it a very desirable appliance nor would needlessly pulling that amount of air out of the kitchen make it a very economical appliance to operate. There is a big difference in sound level between the two operations with my KitchenAid Micro-Convection Oven.

 

[combo52]

OTR MWOs, In One Word.......DON'T

Yes many of the newer cheaper models use the same fan motor to cut build cost, even though it is the same fan motor the grease laden air from below the unit is not being blown over the mag tube to cool it.

 

I recommend to everyone not to install a MWO over a range or cook-top especially a gas range or CT.

 

If you actually do much range or CT cooking they can have a very short life AND they are a terrible fire hazard, these OTR MWOs are not even legal in most of Europe.

 

When you add a MWO to your kitchen either build a spot for it or hang a GE Space-Saver MWO under the wall cabinets instead.

 

If you do a nice kitchen and build in a MWO, buy at least TWO of the same model from the start if you are going to live in the house for at least 10 years and use a MWO much, that way when the original craps out you can just switch it out easily.

 

John L.

 

[DADoES]

 
The GE Profile OTR that was in my kitchen for 15 years and the GE non-Profile that theoretically will replace it after we finish destroying the kitchen cabinetry both have a separate cooling fan for the magnetron.  The airflow exhausts through the same top/front grill (recirculation, not outdoor exhaust) as the hood function but the hood function is a separate dual-squirrel-cage blower.  The hood intake of course is under the unit.  The magnetron cooling intake is at a grill at the right above the control panel.  Configured for outdoor exhaust the magnetron cooling outflow would be the same but the exhaust outflow would be at the top/rear.

 

[superocd]

I'm glad I replaced my OTR micro

When I bought my house, I remodeled the kitchen and replaced the circa-2004 appliances, flooring, countertops and cabinets. I bought a Whirlpool kitchen package, which included the OTR micro, and regretted that I didn't just buy a high-CFM range hood (as I did eventually). Even though the micro had a straight shot through the roof, it seemed to make a lot of noise but not move a lot of air. I wound think that the airflow oath from the intake on the bottom to the exhaust out the top or back would have a lot to do with how weak OTR micros are in exhausting, as it basically has to move the air around the oven cavity.

Going back to what I remember, the WP micro I had was a tad quieter in micro mode but not by much. Every standalone micro I've used had quieter cooling fans than OTR models -- in fact, the hum of the transformer made the most noise.

I have wondered about the grease issue on OTRs if the exhaust fan is used to cool the components. Even if it had a separate cooling fan, I would think grease would meander its way in due to the proximity of the cooktop surface and the fact that every fan needs an intake of some sort to work. I've always cooked anything "greasy" outside but I still boil things on my stove, which also had me wonder about steam/condensation. Not really a worry of mine anymore, as I took out my OTR and went with what I really wanted -- a range hood with almost 400 CFM and a standalone micro on my counter -- but was always curious about the construction and design of these things.

 

[mattl]

A cheap OTR may use the fan for both, but not a decent one. Having an OTR for 30-40 years - without issue - I have no problems.  I replaced a working 15 year old model 10 years ago with a convection microwave model and it's still going strong.  Love to roast a chicken or bake a small amount in it.  The 400 cmf blower is more powerful than many range hoods, and has a decent draw.

 

Everyone has their opinions. I choose not to clutter my countertop up with a microwave. For me OTR is fine, does the job and looks fine.

 

[philcobendixduo]

My 1988 GE JVM150.....

......has a separate fan for the magnetron. The instructions say that the vent fan will automatically turn on if temperatures under the unit (from cooking) reach a high level but I have never had that happen.
I wish my unit could have been vented to the outside but it's downstairs on an inside wall which makes that impossible.
Thankfully, I don't cook a lot!

 

[petek]

Never had one but I did consider it when we bought the new stove last year, to replace the builder grade Nutone exhaust hood. I'm glad I didn't now. I agonized over what hood to get, maybe moreso than any other appliance purchase I've ever made. Not sure why LOL. Ended up with a Broan Elite 600 cfm and boy does the sucker suck. It's a straight shot out the back of the hood thru the wall. On high it's not horribly noisy and you can feel the wind it creates a few feet away from the stove.. Nothing escapes it.

 

[tolivac]

I have had OVR GE Advantium ovens for ever since I moved into my current house-almost 25 yrs and have had NO problems with my Advantium cookers and fires.These had a separate blower to cool the magnetron.One of my Advaniums died a few years ago replaced it with a new one.

 

[fan-of-fans]

I think the OTR microwaves in theory are a good idea. They save counter space in smaller kitchens and generally look better than a cheap-o Broan hood.

But I hear in general the exhaust is not very powerful.

One idea I have seen in some homes is to use an OTR microwave somewhere else in the kitchen other than over the stove. I hear they make great exhaust fans for countertop appliances that don't make as much in the way of fumes - slow cookers, electric grills, steamers, etc. And save counter space as well without being over the range.

 

[circlew]

The best way to install a microwave is built-in to a cabinet at the proper height. The cabinets come in various widths and depths to accomodate any size MW oven and its trim kit. Some are tall cabinets with a pull-out shelf (usually called a microwave cooking center), wall cabinets, or base cabinets, which can be standard height or taller, such as 40.5" high. This way no one has to reach over a hot range top, and it doesn't take up counter space. This also allows a decent hood to be installed, preferably with the power unit mounted outside, such as on the roof.

 

[electro]

OTR Microwave question

Ok,you got me thinking about this thread so I just had to go check mine!

Mine is a combination Microwave/Convection oven. I love the features and what I really bought it for was the powerful LED lighting for the range top.
I never use the Convection part as I have 2 ovens in the range.

I did the test and mine does have the 2 separate fans. They do not sound alike and the exhaust fan has 4 speeds.

I also like the position of the controls on this microwave oven except there is
a design flaw. Some owners have had a problem with the cable that goes through the door. It seems some owners have had this cable fail after several years.

As I said I bought it for LED lightning. I bought one of the last 40" double ovens from Frigidaire which I love but I needed more light.

I solved the possible future wiring issue by buying a Frigidaire microwave for the counter. To be honest I never liked the idea lifting hot dishes up to the OTR microwave anyway.

I also tested the counter top microwave and I do believe it uses the SAME fan for both function. Of course it was MUCH less expensive than the OTR model.

 

[steved]

We ditched the OTR microwave

When we moved here we took advantage of having a larger kitchen and went with a separate hood and microwave. I bought a Sharp Carousel at Walmart.com for $150 and a recessed hood from eBay. The micro is 1100 watts and is more than sufficient and we have a powerful exhaust to outside. Plus the micro is away from the range area.

 

[gusherb]

Before my aunt started building her house she said she was gonna get a proper range hood. Next thing I knew, she was cheaping out and going with an OTR microwave and downplaying everything I had said about why she should get a regular range hood.

Fast forward to now, the thing is noisy and useless. It is vented through a 4” pipe and you can tell it’s moving air but the lack of a proper hood design to catch the heat and odors makes it pointless to even run.

If it was my house I’d have installed one of those 1200 CFM externally mounted blowers with variable speed control and make damn sure the house never filled with fried food odor.

 

[paulg]

OTC microwave ovens / Over The Counter

I forgot about the OTC microwave. SteveD has installed an over-the-COUNTER microwave oven which has no vent feature but a surface light. It looks like a countertop oven but is actually designed to be mounted above the counter. Smart design.

 

[combo52]

OTR MWOs, In One Word.......DON'T

Hi Rob, reply #13 You should not leave the metal shelf in your MWO if you are using it for MW cooking UNLESS you have two large plates of food in the MWO at the same time, one on each shelf.

 

We get calls every week that  shelf supports caught fire or just melted and burned, check out your owners Manuel if you have any question.

 

John L.

 

[electro]

John,
Thanks for your CORRECT advise. I never use the shelf in normal use. The shelf was in there as I was going to "test" the Convection part of the oven just once.
I got the book out to check about using the convection part ONLY.

That was very kind of you to catch that in the picture. I am going to REMOVE that shelf RIGHT NOW!
I would hate to mess this microwave up as it has lots of nice features and I like the very powerful led lights,controls at the bottom of the door and the stainless interior.
I also like the new counter top Frigidaire but it has fewer features and a plastic liner and it cost about 1/6 the cost of the OTR Professional.