Bezzera BZ10 trips circuit breaker, microswitch replacement?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
aoleg

#1: Post by aoleg »

Hello everyone! This is my first post here.

I've got a Bezzera BZ10. Long story short, after 5 years of service, it tripped the circuit breaker with a "poof" coming from the bottom of the machine. I opened the case, and discovered that there is an microswitch labeled as 7633907 on pages 21 and 22 https://espressoperfetto.de/media/wysiw ... s/bz10.pdf

That microswitch is located directly under the water tank. Its purpose is monitoring the water level and to shut off the power (heating element, LED, pump) when the water tank is empty. Due to water leaks occurring when refilling the water tank, the switch looks calcinated, and the contacts are corroded; I believe some water entered inside the switch, too. The switch is pictured here Help with Bezzera BZ10 - No Lights and No Heat. I don't see any other part of the machine being calcinated or oxidized. The switch smells of burned isolation.

I have no problem ordering and replacing the switch myself, but is there a chance there is a bigger problem somewhere other than the little switch? Is there anything I should do or check after replacing the switch and before powering on the machine?

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homeburrero
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#2: Post by homeburrero »

aoleg wrote:I have no problem ordering and replacing the switch myself, but is there a chance there is a bigger problem somewhere other than the little switch? Is there anything I should do or check after replacing the switch and before powering on the machine?
I assume that it tripped the residual current device in your breaker. One thing that can be done if you are competent with electrical wiring and safety would be to temporarily wire a simple bypass that replaces that switch. Make absolutely sure that your bypass wiring is well insulated, then button the machine back up, make sure there is water in the reservoir, and plug it in for a test. If it still trips the RCD in your breaker when that switch is bypassed then you know you have a problem somewhere other than that reservoir switch. If it works fine with the bypass then a new switch ought to solve your problem.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

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cafeIKE
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#3: Post by cafeIKE »

If water has leaked into the connectors, better replace them. Connection is likely corroded.

Something like this is invaluable for testing.


Cover with a length of thin plastic tubing so you don't inadvertently let the smoke out. Once you let the smoke out, most things fail to function. :wink:

aoleg (original poster)

#4: Post by aoleg (original poster) »

homeburrero wrote:I assume that it tripped the residual current device in your breaker.
I assume the same. Instead of wiring directly, I ordered a replacement part, which I plan to install after cleaning the corroded contacts. Hopefully that'll be enough of a fix.

What puzzles me is who designed it so that a 250V-rated microswitch is located directly under the open water tank with zero protection. There is even a hole in the steel cover above that switch to ensure that any water leak lands immediately on the microswitch. I will try replacing the switch and see what happens.

aoleg (original poster)

#5: Post by aoleg (original poster) »

cafeIKE wrote:If water has leaked into the connectors, better replace them. Connection is likely corroded.
Something like this is invaluable for testing.
image
The connectors are, indeed, corroded (electrocorrosion). My plan was cleaning them up before reconnecting, but maybe replacing them is a better idea. Do you know the name of that thing? I'll need to source three wires of specific length to replace.

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cafeIKE
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#6: Post by cafeIKE »

The thing is a reservoir water level switch @ Espresso Care


IF the wires are long enough, you can cut back until you have good wire and re-terminate. It's not necessary to use the large insulators. The connectors are 1/4 Fastons available at almost any hardware store. You likely need both blue [power] and red [lamp]


You MUST use a proper crimp tool

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homeburrero
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#7: Post by homeburrero »

aoleg wrote:I ordered a replacement part, which I plan to install after cleaning the corroded contacts. Hopefully that'll be enough of a fix.
It most likely will fix it, and since your old one was visibly corroded it should be replaced anyway, so money well spent.
aoleg wrote:Do you know the name of that thing?
The thing with the red wire in Ike's picture is just a short length of wire with a 1/4" male 'quick disconnect' blade connector crimped to each end. Perfect for bypassing any switch that also has 1/4" male blade connectors. It just simulates a switch in the always closed position.

I can't tell for sure, but I think your BZ10 tank switch is different and may take spade or fork connectors with a 90 degree bend.



New connectors like this may be a little harder to find, and the one on the bottom needs to handle two wires. If there is no evidence of heating or burning at the connector and they clean up well I think you might just keep them as is.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

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cafeIKE
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#8: Post by cafeIKE »

If water got in them and there is the least bit of corrosion, it's best to replace.



You pays me now or you pays me later :cry:

aoleg (original poster)

#9: Post by aoleg (original poster) »

homeburrero wrote:If there is no evidence of heating or burning at the connector and they clean up well I think you might just keep them as is.
No burning marks on the connectors that I can see, just some visible rust. The part should arrive tomorrow; we'll see how it goes.

aoleg (original poster)

#10: Post by aoleg (original poster) »

The new microswitch has arrived. The replacement fixed the issue; the machine now operates normally.

I attached some pictures of the damaged part.