La Scalla Butterfly Switch Keeps Failing

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

#1: Post by daviddecristoforo »

I have a twenty year old LaScala Butterfly. Over the years it has seen many modifications, converted to a rotary pump, gauge upgrades, etc. Recently it has been gone through and virtually everything in it has been replaced. All sensors, valves, pstat, control box and pump are new. Pretty much the only parts not recently replaced are the boiler and the pump motor.

But... for some reason, the power switch keeps failing. It will work fine for a week or two and then, for no apparent reason, it will refuse to power on. I replace the switch and it works fine for another week or two and then it fails again. I've replaced the switch for or five times now. On guy suggested that it was because the machine was plugged into the same circuit that my fridge and/or microwave was on. That sounded unlikely to me but just to be sure, I connected the machine to a dedicated 20 amp, properly grounded circuit with nothing else connected. A week later, the switch failed again!

Does anyone have any idea what could be causing this? Something is obviously overloading the switch. It's a rocker type switch (https://www.drtradingshop.nl/en_GB/a-52 ... escription) I'm wondering if it would make sense to replace it with a heavier duty toggle type switch. I think the switch is rated at 16 amps and I can get a 20 amp toggle switch.

Also, I have a shot timer wired in (https://www.auberins.com/index.php?main ... cts_id=920) but I don't think this is causing the problem simply because the problem existed before the timer was added and the timer only consumes two watts.

Any thoughts?

ira
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#2: Post by ira »

Because I'd want to keep it looking like it does, I might just put a relay inside that the switch controls so it's not switching the power to the heater. But you have to have space, a way to mount it and the knowledge of how to wire it. Here's a couple that might work:

https://www.mouser.com/ProductDetail/Sc ... r1Ew%3D%3D
https://www.mouser.com/ProductDetail/Om ... dgFw%3D%3D

A lot of the switches in home espresso machines seemed to be specified for 220V machines and are overloaded for 110V machines though I've never heard of one dying that fast before.

Ira

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daviddecristoforo (original poster)

#3: Post by daviddecristoforo (original poster) »

Ok... you might be on to something. When I first installed the rotary pump I had it connected through a relay. When the shop went through the machine they took the relay out and wired the pump directly into the control box. Possibly this is why the switch keeps failing? It would be easy to wire in another relay and they are not expensive. Do you think this might solve the mystery?

PS I'm not worried about it looking the same so if a heavier duty switch would be a good solution, it would be easier to go that way...

JRising

#4: Post by JRising » replying to daviddecristoforo »

The shop removing your sacrificial relay for the pump would really only cause more stress to the control-box that now runs the pump directly, the overall consumption of the machine shouldn't be higher so it shouldn't concern the power switch...

Does the power switch display its rating? Ira's correct about the Italian machines coming to America with under-rated switches and old QuickMills dimly illuminating their 220V neon lamps, etc.

daviddecristoforo (original poster)

#5: Post by daviddecristoforo (original poster) »

I believe the switch is rated at sixteen amps. I'll double check this. The switches have been provided by a local shop that sells the LaScalla machines. The same shop that replaced all the valves and pstat.

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BaristaBoy E61

#6: Post by BaristaBoy E61 »

daviddecristoforo wrote:Does anyone have any idea what could be causing this? Something is obviously overloading the switch. It's a rocker type switch (https://www.drtradingshop.nl/en_GB/a-52 ... escription) I'm wondering if it would make sense to replace it with a heavier duty toggle type switch. I think the switch is rated at 16 amps and I can get a 20 amp toggle switch.?
While I do agree with Ira & John they have not gotten to the original cause of the problem. Yes, installing a relay of sufficient voltage and amperage is a good idea as is replacing the original power switch with one that can handle 25amps at 125v would be if one would fit in place of the original power switch.

The origin of this problem is likely not the current handling capacity of the power switch or of a relay. You will likely still experience the same issue with higher capacity components.

The solution is the installation of .01mfd/450v ceramic disk capacitors across all high current switching devices, power switches or relay contacts. It is the momentary arcing and sparking of these contacts (probably measured in milliseconds) during every cycle that each is activated that is causing carbon build up and higher contact resistance of the switch or switching contacts that is the problem. The capacitor will short out and effectively absorb these arcs and save the contacts from pitting, arcing, and carbon deterioration.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

daviddecristoforo (original poster)

#7: Post by daviddecristoforo (original poster) »

That sounds interesting but I'm totally in the dark as to how to do this. Would you be able to provide a simple diagram?

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daviddecristoforo (original poster)

#8: Post by daviddecristoforo (original poster) »

Can anyone shed a bit more light on this capacitor idea?

ira
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#9: Post by ira »

If you get AC rated capacitors and put them across the switch, they may limit arcing when you turn the machine off. But I will point out that it's difficult for me to imagine that if you're really killing a switch in a week or two that adding a capacitor will have any effect. The switch should be rated for 10,000 operations if it's really the proper switch. If you still have one of the dead ones, open it up and show us a picture of the insides, that should let us see the failure mode and be better able to suggest a resolution.

Ira

daviddecristoforo (original poster)

#10: Post by daviddecristoforo (original poster) »

I'll pull the switch and try to get some pics. Also, I'm looking for a diagram for wiring a relay. Do I just connect the leads from the control box to one side and the motor leads to the normally open contacts on the other? Or do I need separate power leads for the motor?
Appreciate all the advice so far...
Thanx
DD