Ok, so something bad happened yesterday to my Quickmill 0835. Turned it on, left the room, came back half an hour later to make a coffee. Started to steam milk... steam was weak and then.... it just stopped. Milk was barely warm. Hit the brew, nothing happened! Hit the steam again... dead silence (instead of the usual loud pulses). Boiler doesn't heat up, temperature light does not come on, steam does not come on. This is a combi model with a grinder and an electronic control board. That would point to a blown fuse. However, both the grinder and power light comes on!

At first I suspected the fuse blew, because it blew recently. But the fuse was intact, and I've confirmed the grinder doesn't work if the fuse is out. The reason it blew recently was because I was doing some work inside the machine, and mixed up a couple of the wires. So they should all be correctly wired now, and I have since made an espresso and steamed milk after changing the fuse, with no issues. I checked top and bottom for signs of water, and the circuit board for signs of burning damage. Found none. So... kind of without a clue here. Can anyone point me in a direction as to where the fault might lie? I'm not ready to contemplate what life would be like without my Quickmill...

Is there an overheat breaker on the boiler?

Good question! Very possible. If you see in the photo, there is a contraption inside a clear plastic tube that sits on top of the boiler, called a "safety thermostat". It looks like it may be a tiny little fuse that protects the boiler from overheating. When I tested the ends of the metal wire for conductivity, there was no signal.

I don't know if this is enough to prevent the boiler, steam, pump and temp light from turning on, but it may be that these functions are designed to not work if the heater doesn't work. I'm wondering now how to confirm this? Can I take the fuse out and maybe just connect the remaining wire together to see if I will get my brew/pump/steam/temp light back? If only for a few seconds to confirm that this is a fuse that blew? It'd sure be good to confirm this before I order a new one.

That would be a thermistor. There are two different types, one opens or with heat and the other closes with heat. More than likely that is your problem, but i would try and figure out what is causing the issue.

Yes, that is exactly what it was. Quickmill dealers call it a "safety thermostat". I believe it's designed to trigger at 167C. I tested it for continuity, there was none. So if I have my terms correct, this "thermistor" is the type that opens with heat. As for trying to figure out what the cause of the issue was, I wouldn't even know where to begin. All I know is that I let the machine heat for about a half an hour (before trying to make a coffee), while I was out of the room. Normally, I don't heat it up that long before pulling a shot. Perhaps the boiler was dry, and the little thermoblock boiler doesn't like being heated for long on dry?

Would you know if my "thermistor" is a standard electronic component, like a glass fuse; or if I have to try and get one from a Quickmill dealer?

For future reference, please do not cross-post to HB. See Why is cross-posting strongly discouraged? for the rationale behind this policy. Contributors may wish to reference this post on the same subject to avoid needlessly repeating the same suggestions. Thanks.

Actually, it's a thermal fuse. A thermistor is something else entirely. Glad you found the problem.

Technically you are correct. Commonly they are referred to as a thermistor as they are very similar in looks to a resistor.

Nunas wrote:Actually, it's a thermal fuse. A thermistor is something else entirely. Glad you found the problem.

+1 100%!

Read the temperature on the blown fuse & order 2. It's a $5 fix. If you're not familiar with electronic repairs, buy the part and bring it to a competent service technician.


https://abra-electronics.com/fuses-fuse ... e8103.html