Hi all, possibly a stupid question, but I'm trying to confirm whether or not there's something wrong with my microwave before replacing/modifying it. It's a GE JVM1540SM5SS OTR microwave (picture attached). It's vented to the outside. My problem is (possibly) with the intake for the vent. I'm not sure that it's really any good at actually drawing air up away from my gas range.

The microwave has a slotted grill along the top front of it, with two small intakes for the vent behind the grill (red arrows in attached picture). I confirmed that it does suck air in here, by loosely holding tissue paper near these spots and having it adhere to the grill from the air pressure. However, I would expect that the vent would primarily draw in air from beneath, where the blue arrows are in my diagram. There are grease traps down there. The problem is, I don't think that it is drawing in air from there. I never see any effect on steam rising from my cooking when the vent's on, and the same tissue paper test underneath the microwave has no effect on the paper. Maybe it's a small thing, but it just doesn't seem to be working properly.

Is this something that I could change? Some alternate means of routing the airflow so that it draws in from the bottom, rather than the top? For what it's worth, the grease traps don't seem dirty at all, and I really don't think the previous owners would have cleaned them. Or is there a good way to test and see if the vent is in fact drawing in air from the bottom, besides observing steam or the tissue paper I used?

 

Welcome to the forums.

Based on this...........
On models shipped for non-vented exhaust, a disposable charcoal filter is included with the oven and
needs to be installed to help remove smoke and odors.

On models shipped for outside top exhaust, a Charcoal Filter Accessory Kit is required for the non-vented exhaust. (See your Owner's Manual for the kit number)

It looks like your microwave/vent hood is setup for recirculating which means there is no outside vent and the air is just circulated thru the microwave. In at the bottom, thru a charcoal filter and out the top.

Can you confirm there is an outside vent/discharge ?

Owners manual - pdf
Installation manual - pdf