Quick Mill Anita - High Limit Burnt?

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mattrichards
Posts: 12
Joined: 10 years ago

#1: Post by mattrichards »

Hello Everyone,

I have a relatively new, lightly used Quick Mill Anita that I bought from Chris' Coffee a while back. Recently it stopped heating when turned on. I popped the case open and found that one of the wires coming from the high limit appears to be burnt (see image below). I've sent this info over to the service guys at Chris' Coffee, but I was interested to hear if anyone here had seen this before. If so I'd love to know if the cause was determined and how you went about resolving the issue.

Thanks,

Matt


ira
Team HB
Posts: 5497
Joined: 16 years ago

#2: Post by ira »

The picture is not quite good enough to give a definitive answer, but that happens in general because of a high resistance connection. In your picture I can see the metal of the crimp connector sticking out the end of the plastic insulator, that's not correct and likely means that the metal part connector was not making good contact with the tab on the switch. That is an assembly problem from the factory. i.e., it likely failed like that because someone at the factory was not paying attention when the put your machine together.

Ira

ChileBean
Posts: 100
Joined: 10 years ago

#3: Post by ChileBean »

Hi Matt,

Yikes! I have the same high limit switch in my new Carola, so I hope this is not a regular thing.

Mine works fine, but looking at the photo, it does not look like there was any arcing from the wire to the chassis, so the most likely cause of this problem would be a dirty or insecure connection between the connector and the limit switch. It could also be a bad crimp (not enough crimping pressure) between the wire and the connector. Since the boiler draws quite a bit of current, even a slightly dirty connection can cause a big temperature rise at the connector. I will be curious to see what Chris' says, but that's my guess.

(Ira beat me to the punch - as I was writing this, I see his post. but he is correct - if there is metal visible above the body of the connector where the wire enters, then the person building the unit did not properly seat the metal pin inside the connector body properly. In any case, it seems Ira and I are both thinking the same thing, so that probably means both of us are wrong (just kidding).

Brad

ira
Team HB
Posts: 5497
Joined: 16 years ago

#4: Post by ira »

It's not a bad crimp because of the location of the burn, if it was that, the burn would be at the top near the metal sticking out.

Also, the wire would have likely gotten hot.

Ira

mattrichards (original poster)
Posts: 12
Joined: 10 years ago

#5: Post by mattrichards (original poster) »

Thanks for your quick feedback guys. Much appreciated.

Apologies for not getting a better shot, but it's a tough spot to shoot without removing the top plate - which I'm not sure how to do correctly as it's connected to the boiler pressure adjustment. Assuming that the extent of the damage is shown in the image, is it just a matter of replacing the high limit and the blue cable?

As may be obvious by this point, I'm not well versed in what goes on "under the hood" so to speak... :)

Matt

ira
Team HB
Posts: 5497
Joined: 16 years ago

#6: Post by ira »

Yes, replacing the cable and high limit should fix the problem. The switch should be easy, but check to see if has thermal paste and if so, make sure to use some. If you need, I'll send you some for the postage. It comes free with every heatsink and I use the expensive stuff so I've lots of left over little tubes. The wire might be trickier as it's common for some of the wires in an espresso machine to get crimped together. Hopefully it's just got one connector at each end. If you can't find one, tell me what it is and I can make you one. Can't match that shade of blue, but the one I make won't fail If you were closer, I'd say, drop over and I'll crimp a new connector on it and I have the same connectors and the proper tools, but Los Angeles is a bit of a hike.

Ira