How to test espresso machine without tripping the whole place?

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

#1: Post by Flitzgordon »

I've a Bezzera which has a problem with power trips.

I've disconnected the heating element and pump and it still trips.
It's annoying and probably dangerous each time it trips, it also pulls the circuit breaker and shut the whole place


How do repair centres isolate and keep the power trip localized?
I've tried one of those RCD Masterplug adaptors and they don't work.

Living in a location with 220-240V

Marcelnl
Supporter ♡

#2: Post by Marcelnl »

an extension cord with a earth leak detection breaker? or a workbench with a separate earth leak detection breaker?

https://www.yourtools.nl/nl/adapters/po ... 7-327.html
LMWDP #483

bean74

#3: Post by bean74 »

I'm an EE, but I don't know code in Denmark. Assuming this machine is installed somewhere near a sink, and that Denmark may also require ground-fault interrupt breakers on any receptacle within 2 meters of a plumbing fixture (eg. sink), there could be two causes for those breaker trips:

1. Overcurrent. In the USA, residential breakers have two trip mechanisms: thermal and magnetic. The magnetic trip is fast, designed to catch a short circuit, and typically set around 10,000 amps in the USA. You would be able to easily detect a short circuit with an ohmmeter, measuring between each pair of the three pins on your power cord (unplugged, of course). The thermal trip is slow, from tens of seconds to tens of minutes, depending on how far you load the circuit above the rated current. So, a 15 amp circuit loaded to 17 amps might take 1 to 15 minutes to trip, depending on other factors (breaker cabinet temperature, adjacent circuit loads, etc.). I would imagine the same two mechanisms are employed in residential breakers used in Denmark, it only makes sense, although the numbers are surely different.

2. Ground fault. In the USA, residential outlets installed in kitchens, bathrooms, garages, and basements require a ground fault interruption feature. This is designed to shut off power if current above a given threshold (5 mA, if I recall) is detected between line (110VAC) and ground. Historically, these mechanisms resided inside the breaker (GFI or GFCI breaker type), but folks found that too much a hassle, so most installations put this mechanism inside the outlet today. If you are tripping a GFI outlet, you have a current path from line to ground, not a circuit overload.

If you tell us the type of outlet and breaker you have, we may be able to lead you through a debug process, to find the source of the trouble. Also, do keep in mind that breakers installed in damp basements do go bad over time, it's possible it is tripping below its rated current. It's also likely a loose wiring connection in the path from machine to breaker could be generating sufficient heat to cause a trip, when there is nothing actually wrong with your machine. My mother once replaced an air conditioner due to this loose wire problem, only to have the new air conditioner trip the same circuit.
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Giampiero

#4: Post by Giampiero »

Just to understand better, the machine was working regularly and then suddenly had the issue?

Flitzgordon (original poster)

#5: Post by Flitzgordon (original poster) »

I am now located in Hongkong for work.
I measured the continuity between all the terminals and the chassis.
Identified a torn cable, taped it back with electrical tape and it's now without the trips.
I'm considering replacing the cable but I've to figure out the right specification for it.

I also found the main switch with some continuity in its off position and have that replaced.

I measured the 3 pin plug between the live and neutral out of curiosity, the resistance(set at 2k), and it reflects 0.4.
I've another working machine and it measures 2.x at the same spot.
I noticed that the regulator has some unusual marks in the circuity.
I swapped the regulator from the working machine with the machine that had fault, and the reading is now 3.x
Does it mean anything?


I wonder if there's anything else since there's more than one fault.
The heat is working, refill working fine, pump works too.
I measured continuity between every terminal of every component with the chassis, and there's no more open circuits discovered other than the torn cable.


If I get my hand on a insulation tester aka megger, would that be useful for such diagnosis?
If yes, where should I measure with it? Can I measure the whole machine and at which points should the measurements be made?

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homeburrero
Team HB

#6: Post by homeburrero »

Flitzgordon wrote:If I get my hand on a insulation tester aka megger, would that be useful for such diagnosis?
An insulation tester / megger in the right hands can find a ground fault that may not be detected with a multimeter. It does that by applying a much higher voltage to the test leads than a multimeter would. This voltage could be hazardous to you or to the equipment you are checking. If you find a qualified electrical repair person with a megger, let the electrician do the testing. They will best know how to use their test equipment safely and effectively.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h
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bean74

#7: Post by bean74 »

Flitzgordon wrote:I am now located in Hongkong for work.
I measured the continuity between all the terminals and the chassis.
Identified a torn cable, taped it back with electrical tape and it's now without the trips.
I'm considering replacing the cable but I've to figure out the right specification for it.
Which "cable"? If you are referring to the external cord set (aka power cord), then assuming your machine has the usual IEC C13 plug on the back, you can buy one from any appliance store or order from Amazon. Be sure it has the proper plug for Hongkong on the other end, and it's rated to 1350 watts (6A @ 220V) or higher, which likely any are, 10A is a very common rating for IEC C13 cord sets.

If you meant a different cable, please describe. If inside the machine, don't expect electrical tape to work, it's likely too hot for the adhesive. Use heat shrink tubing, or just replace the wire.
Flitzgordon wrote:I measured the 3 pin plug between the live and neutral out of curiosity, the resistance(set at 2k), and it reflects 0.4.
I've another working machine and it measures 2.x at the same spot.
Most modern DMM's auto-range, but if yours is manual, you'd want to measure at a much lower setting (eg. <100 ohm) to get more accurate readings. I haven't tested a Classic this way, but I believe that if you unplug the wires to the 3-way valve, everything else (with power switch on and pump switch in off position) should be purely resistive loads (heaters + incandescent indicators), and that you should see about 36 ohms line to neutral on a machine wired for 220V operation. Either line or neutral to ground should be open circuit, or at least a few multiples above 50 k-ohm, to avoid tripping GFI outlets or breakers.

Activating the pump or 3-way solenoid will appear as very low resistance to a DC ohmmeter, solenoid coils have relatively low DC resistance.

If you have a clamp-on ammeter, or a DMM with a pass-thru ammeter current rating of 20A, this is a better way to debug the machine. Just be careful with switching your DMM to amps, it turns it into a dead short, which will ruin your morning if you forget to switch it back off this setting before measuring anything live with it at 220V.
Flitzgordon wrote:I noticed that the regulator has some unusual marks in the circuity.
I swapped the regulator from the working machine with the machine that had fault, and the reading is now 3.x
Does it mean anything?
Regulator?
Flitzgordon wrote:If I get my hand on a insulation tester aka megger, would that be useful for such diagnosis?
If yes, where should I measure with it? Can I measure the whole machine and at which points should the measurements be made?
This would really only be useful in testing insulation resistance of wiring or thermostats. I wouldn't waste my time on it, too likely to cause damage in the wrong hands, and not likely to reveal much of value.

Flitzgordon (original poster)

#8: Post by Flitzgordon (original poster) »

The cable is internal and is connected to the grouphead and it's exposed to constant high temperature sitting on the hot brass.
I've some heat shrink tubing and it's stated 125 degree celsius on the cable, but i am not confident that it will be able to withstand the high temperature all the time.
I haven't tested a Classic this way, but I believe that if you unplug the wires to the 3-way valve, everything else (with power switch on and pump switch in off position) should be purely resistive loads (heaters + incandescent indicators), and that you should see about 36 ohms line to neutral on a machine wired for 220V operation
Do you mean live to neutral on the plug?
I've disconnected all the solenoids and that did not change the reading.

I'm planning to get a clamp on ammeter, the space is rather tight, where will be a good spot to read?

The regulator is the mainboard from Gicar

bean74

#9: Post by bean74 »

Again, USA reference, but our residential power has 3 wires typically identified as hot, neutral, and ground. Based on your earlier posts, it sounded like you were using the same convention, so yes... hot to neutral, as in the two conductors carrying the primary current of the appliance.

Clamp on ammeters just need to clamp around a single conductor, as clamping around a pair will cancel the magnetic field used to read the current. So, you can't clamp around a multi-conductor power cord, but you can clamp around an individual wire coming off your power entry module, assuming there's space there. You can also check individual branches within the machine, like heaters, if you determine the total draw of the machine is above spec.

Sorry, I don't know any details on your particular machine, I don't own the same machine.

dyno

#10: Post by dyno »

I had this problem with my Spaziale and it ended up being the hot water solenoid. Took awhile to figure it out.