All ORTs vent upwards in recirculating mode. They are not designed to work with 14”D cabinets. They are designed to work with 12”D cabinets. You’d need a custom stainless spacer at the rear if you were to bump it out 2”.

All ORTs vent upwards in recirculating mode.

Recirculating mode has nothing to do with it; the microwave was being used as a microwave, not as range ventilation.

My cabinet maker put 14 inch depth cabinet for my microwave to mount under. I can bump out the microwave to allow the top vents exposure but it still will be putting moisture upward.

Post the manufacturer recommended installation requirements and photos showing how it was actually installed, please. If the two are at odds, you need to speak with your cabinet maker and/or Samsung to resolve the situation—if it needs resolving.

Here is a link to the manual and screenshot below
http://downloadcenter.samsung.com/content/EM/201712/20171226114452014/SMH1927_XAC_DE68-04108B-02_EN-CFR.pdf

Last one. I can bump it out but moisture still will go up. I spoke with two large appliance retailers and they say that is just the way it is.

As said, the max depth of the wall cabinet above should be 12”.

You can always do a real hood and put a MW elsewhere.

Agreed and I can bump it out but I'm still not liking the idea that moist sir blows up on my painted cabinets. It seems strange that would be a design that would not cause problems.

Can you please post pictures of your actual installation that shows how it’s vented? Do you have any problems when you’re using the exhaust fan part of it for stovetop cooking or is it strictly when using the microwave to cook things? Just trying to make sure I understood your original post.

But really, do you know why the cabinetmaker made the cabinet 14” deep? That’s the major question, here. You’d be surprised at how much of an impact not following installation clearances—even if it’s only 2”—can make. Actually, the bigger question is, who did the microhood install and why didn’t they follow install instructions?

He told me to 14 inch deep to accommodate the microwave and have it be flush with upper. If I was going to use my old microwave it would have been ok. I indicated I was getting new microwave and I had to provide him with the model. I have a call into him.
The issue occurs while using the microwave

1. I think everybody assumed that this was a recirculating microwave oven, i.e., an oven without a duct that exhausts to an outside wall or roof.

2. A modern recirculating oven will exhaust through the top-front of the oven.

3. The last picture shows that the upper cabinet contains a duct. If the microwave has been configured correctly* and the duct is attached to the oven, you shouldn't feel any exhaust coming from the front or top of the oven.

4. Per the installation manual, this model is designed for a cabinet of 12" maximum depth.

5. The Whirlpool WMH53521HZ 30 Inch Over the Range 2.1 cu. ft. Capacity Microwave Oven (top-rated by Consumer Reports) can be used in a 14" deep cabinet. The oven will protrude from the front of the cabinet.

*for upward exhaust.

Many microwave ovens can be configured to vent out the top (into a duct), out the back (into a duct) or out the top (recirculating mode, no duct).

All microwave ovens have an internal cooling fan for the magnetron. It typically also exhausts some air/moisture through the cooking cavity.

OTR units typically exhaust that cooling air from the top/front.

My GE does the same.

Mine is installed in non-exhausted (recirculation) configuration. It has a motorized vent panel that opens during operation ... BOTH with the vent hood function ON, and with it OFF (only the microwave operating).

The builder / kitchen designer of my house put a bunch of fancy trimwork around the microwave, which overhangs it and effectively blocks the airflow from going upwards, directing it forward into kitchen and/or into the face of whoever is standing in front of it.

Countertop units typically exhaust it out the back which makes the airflow much less noticeable.

Panel open

There's supposed to be a charcoal airfilter set into the top of the unit, accessible to change or clean by pulling the panel open. The filter isn't there, and it wouldn't be accessible if it was because the trimwork blocks access.

I agree but mine is vented to the outside. I’ve been to two different appliance stores and they say they never heard of this happening

They never heard of it because 98% of the people using an OTR use the 12”D cabinets that it was designed to be used with.

Agreed but there is still moisture coming out and they all agreed that indicates it’s a seal problem with the door. Both stated that irregardless moisture should not come out. This vents are for when you are not venting to the outside

Microwave oven doors are not air-tight so I wouldn't assume they're moisture-tight.

My unit has separate fans for cooling the magnetron and for the exhaust hood function. The cooling fan generates MUCH less airflow volume than the exhaust but the vent panel still opens fully and some air can be felt. I can't reconfigure it into outside-vented mode but I assume the cooling fan would vent the same way through the panel in both configurations. The cooling fan airflow isn't enough force by itself to blow properly through an outside duct.

To be sure, there's appreciable moisture sometimes inside the cavity and door (may be a few drips onto the range cooktop when the door is opened) after an extended cooking operation (rice, boiling pasta, etc.) that I leave the exhaust fan running for a while to dissipate it and fully cool-down the unit.

" I agree but mine is vented to the outside. "

The exhaust fan for the COOKTOP is directed outside. The exhaust for the interior of the microwave and the microwave is different.

" Agreed but there is still moisture coming out and they all agreed that indicates it’s a seal problem with the door. "

I'm not sure how you can tell this when it is mounted 2" too deep in the cabinet. Can you see the vents for the oven on the top of the unit?

Yes I can see the vents. If I open the door the vents are directly in line with the cabinet. I see the full vent and see and feel the moisture coming out of the vent. The vents are covered if I close the cabinet door. Even with the doors open moisture accumulated on the bottom rail of the cabinet. So by installing out 2 inches more would mean that with door open moisture would just be further away. Never had moisture come out so visibly from a microwave. I’ve seen I accumulate and when you open the door escape but not going upward while cooking like this does

Update- cabinet maker is bumping out the microwave. They dropped the ball on it having to be installed with 12 inch cabinets. Still have steam going in between the glass and on the outside on the lower part of microwave. It sure why?

Thanks for the update, Kathy - good luck!

Microwave default is recirculating, installer needs to switch it to outside vent? Attaching a duct to the top does not change it, need to physically change the microwaves configuration.

I have this same issue with a new LG microwave mounted under a 12 inch cabinet. It is recirulating and has ruined my upper cabinet doors. I have a formal complaint with LG at the present time. Seems these new up-venting microwaves are destroying the upper cabinets and more folks need to complain.

@HU-836678489: "I have this same issue with a new LG microwave mounted under a 12 inch cabinet. It is recirulating and has ruined my upper cabinet doors."

The LG LMV2031SS and LMV1764ST recirculating ovens are 15.81" and 15.69" deep, respectively. I don't see how the exhaust of ovens that deep can touch 12"-deep cabinets.

I have the exact same problem with my GE microwave, it has destroyed my upper cabinets and I am livid!!!!!!!

I just make sure to open my top cabinets when using microwave. It looks silly having them open but has prevented any damage

@kathy Marano: "I have the exact same problem with my GE microwave, it has destroyed my upper cabinets and I am livid!!!!!!!"

When properly installed, a GE OTR microwave oven -- even when recirculating -- will not destroy the cabinets to which the oven is attached (I have GE JVM3160RFSS). What is the model and the depth of the upper cabinet? Is the oven configured to vent or recirculate? Post a photo; include one from the side.

I've learned to just open my cabinets above while using microwave o make sure moisture doesn't cause damage to the cabinets