crwdns2934065:0crwdne2934065:0: 1
1
Why does my over the range microwave keep shorting out the monitor switches and blow the breaker. I can replace the monitor switch and it will work for a day or two then short out again. I work at an apartment complex and this happens on a lot of them
crwdns2934109:0crwdne2934109:0
crwdns2934065:0crwdne2934065:0: 498,8crwdns2936485:0crwdne2936485:0
11
385
1,5crwdns2936485:0crwdne2936485:0
Hi @doug573
It's a possibility.
Here's some info that may help.
The model is made for Kenmore by Frigidaire as it uses all Frigidaire parts (Kenmore actually don't make any appliances, they just order and rebrand other makes e.g. LG, Whirlpool etc).
Here's the parts list for the model if parts are required.
The manufacturer's part number is listed with each part.
Search online for the part number to find suppliers that suit you best.
Here's a poor image of the wiring diagram that may also help.
As can be seen, if when opening the door with the oven operating, the monitor switch closes before the primary interlock (top door switch) opens, then there's a direct short across the input supply.
(click on image)
crwdns2934105:0crwdne2934105:0
I have tried replacing the monitor switches in several units but it just doesn’t last. I have tested the door switches and they test fine when checking for continuity during open and close. I’m sure it has something to do with residents pulling the door open during operation and not pushing the stop button. I just wish I knew how to correct these as again they have just been replacing them and I bet they have replaced more than 30 of these due to this.
All you can do is when replacing a switch, is to use an Ohmmeter (power disconnected from oven) and check, when opening the door very, very slowly, is if the monitor switch is electrically closed, before the primary interlock has electrically opened, then it may be an adjustment or replacement (worn?) of the switch actuating lever assembly i.e. door latch or the position of the switch itself in relation to its actuating lever.
By using the control panel option to stop the cooking process, the R2 relay on the control board is released, which opens the power path to the HV circuit, stopping it from functioning, preventing arcing across the monitor switch, so even if the latch/switches were out of adjustment the problem wouldn't occur.
Getting people to change their habit of controlling the way the oven is stopped during cooking by just opening the door, may be more difficult ;-)
Just another thought on the problem
Might be best to ensure that the correct replacement monitor switch is installed i.e. search for manufacturer's part number - Frigidaire part # is 5304509459 It is an NC (normally closed) type switch.
Have read that cheaper switches are available online and whilst they're compatible, they are of inferior quality and are prone to earlier failure. Usually opening the door to stop the oven and getting switch failure problems takes a few years or even more to show up.
Cheers
@jayeff thanks for all your help. I greatly appreciate you
crwdns2936751:024crwdne2936751:0 0
crwdns2936753:07crwdne2936753:0 1
crwdns2936753:030crwdne2936753:0 7
crwdns2942667:0crwdne2942667:0 71
crwdns2944067:02crwdne2944067:0
Hi @doug573,
What is the make and model number of the microwave oven?
Is the microwave being stopped during its cooking operation by opening the door instead of stopping or pausing the oven by using the control panel options?
If so this is a good way for the monitor switch contacts to fuse together. Arcing across the contacts.
Also check the operating sequence of the door interlocks because you don't want the monitor switch to close (when the door is opened) before the primary interlock has opened as then there is a direct short across the input supply. Only for a very brief moment but long enough to blow a breaker perhaps
crwdns2934271:0crwdnd2934271:0 jayeff crwdne2934271:0
They are Kenmore model number 790.80333310. Again these are at an apartment complex where I work and I would say this happens about 4 or 5 times a month in different units. They have just been replacing them. Do you think that there could be wear on the door interlock mechanism that could cause this.
crwdns2934271:0crwdnd2934271:0 Doug crwdne2934271:0