Electrical Short in Gruppo Izzo HX Espresso Machine

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
pjanda1
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Joined: 1 year ago

#1: Post by pjanda1 »

Hi, I'm trying to get a Gruppo Izzo HX machine running. I picked it up with some very bad and incorrect half completed repairs. I installed a new control board (old one ruined by bad repair) and a relay (omitted by the "shop" that had worked on it). Chris Coffee provided a schematic that I've attached here. (My machine is not identical, as I don't have a K2, but otherwise the same).

Whenever the relay trips, there is an immediate short to ground. I can't find a short anywhere with my DMM and I've been over and over and over the wiring. The pump (rotary) runs fine if taken out of the circuit and wired directly. I replaced the pressure stat switch. I still have the short even if I disconnect both sides of the heating element. I don't have the short if I disconnect the hot at the relay.

I've been pestering the fine folks and Chris Coffee off and on for weeks and we can't figure it out. Please let me know if you have ideas.

Paul


austinado16
Posts: 387
Joined: 1 year ago

#2: Post by austinado16 »

I think if this was mine, with that schematic in hand, I'd label and disconnect the outputs from the controller and see what it did. If it was fine, I'd connect 1 at a time and see what happens. I'd also try to prove that each of the wires connect to the controller were in the correct position. Maybe the controller you've installed has also been killed by a wire being put into the wrong location?

I just went through a dead Pasquini Livia 90S (which I knew nothing about), and I turned a diagram like yours into a current flow diagram, so that I could see which way power was flowing. It helped me make sense of it better, and it's the method I use as a mechanic on European cars. It also allowed me, with everything disconnected from the controller, to jump power and provide a neutral, to all of the components, and make them work, just to confirm that they did work (and weren't dead, or shorted).

For example, you're machine turns on the red light, a the same time power is fed to the heating element. What if that bulb (which could be a neon bulb with a little "filter" soldered on the neutral) is somehow bad?

It appears that there's a heater for the group? Is that what M G is? Is that thing shorted out? It get's "armed" along with the pstat, the red light, and the boiler element.

Also, are the connections correct at the power relay? It's making 2 connections: 1 passes line voltage, the other passes neutral heading back out of the machine. If hose were crossed you'd be feeding line voltage right into the neutral

Just thinking out loud, I'm no expert.

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BaristaBoy E61
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Joined: 9 years ago

#3: Post by BaristaBoy E61 »

K2 seems like it's a thermal breaker for the boiler heater element. MG seems like it's a Micro switch for the Group.
There's current leaking somewhere that you have to measure and find with you DMM on its most sensitive scale.

Judging by my wonderful experience with Chris' Coffee service techs that if they weren't able to figure it out you'll have to do that yourself but you have a big advantage. You have the machine in front of you and they (Chris') don't!
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

austinado16
Posts: 387
Joined: 1 year ago

#4: Post by austinado16 »

Oh.....I see; MG is a push button that turns the pump on, when you swing the brew lever on the group. D'oh!

This must be what the wiring schematic looks like for the QM Andreja that I'm working on. Mine has the K2 thermostat for the boiler element, but it's on the neutral from the element. It was being shorted out by the Vacuum Valve leaking and spraying on it, causing the GFCI to trip. Someone here turned me on to that, thankfully!

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BaristaBoy E61
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#5: Post by BaristaBoy E61 »

Even on the schematic provided here, I don't see why K2 shouldn't be moved to the other side of the heater element and on to the neutral side. To me that seems safer and will still protect the element.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

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cafeIKE
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#6: Post by cafeIKE »

K2 should be in the line side as shown. A failure that connected the neutral side of the element to neutral or earth in a non GFCI outlet would not break the heater circuit and over heat the boiler.

If K2 is missing, it should be replaced as it is the boiler over temp cutout.
Whenever the relay trips, there is an immediate short to ground.
RL2 or the pump relay on the controller?

Does it trip the over current breaker or CFGI?

You can test each line circuit with a jumper and having all line connection removed from the controller and inserting the jumper one at a time between F1 and F3/4/5.

If F3 trips, then try the pstat directly.
If that trips, try the pstat heating element input.


You might need longer depending on the harness.

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BaristaBoy E61
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#7: Post by BaristaBoy E61 »

cafeIKE wrote:K2 should be in the line side as shown. A failure that connected the neutral side of the element to neutral or earth in a non GFCI outlet would not break the heater circuit and over heat the boiler.
Thanks for the clarification, I stand corrected.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

pjanda1 (original poster)
Posts: 2
Joined: 1 year ago

#8: Post by pjanda1 (original poster) »

I am embarrassed to say that it took me all this time to figure out I had the relay wired incorrectly. I don't work with relays much, and I was wiring it as it appears on the schematic. I peaked at the data sheet for the one I've got (in addition to the side of the darn thing) and realized my error.

Hopefully only a bit of assembly before this is up and running!

Paul