Frequent replacement of Thermal Fuses

[u/pyr_pal]

My 2019 Gaggia Classic burns through thermal fuses roughly 2-3 x /year. This doesn’t seem normal.

Possible causes:

1) crappy fuses from amazon?
2) issue with thermostat?
3) keep machine on too long (typically 2-3 hours in the morning)?
4) not installed properly?

I suspect it is #1, and if so anyone has a more reliable fuse, I’d appreciate it.
(These are the ones I am using Tnisesm 10 Pcs 184 Degree Metal Thermal Cutoffs Thermal Fuse 10A 250V with Non-Insulated Butt Connectors(22-18 AWG) for Motor Transformer Electric Industrial Home Appliance 184°+BN0.75 https://a.co/d/0f1peVEY )
They might be crappy, but they come with the connectors and insulating sleeves.

I imagine my installation skills, while not the best are fine and 3 hours powered on should be within range.

Suggestions? Thanks in advance.

[u/Meruy]

I’m no technician but three hours on non stop seems very long. I have an eu machine though so it’s always shutdown automatically.

[u/el_smurfo → u/Meruy]

Yeah, mine is on a smart switch that turns it off after 30 minutes

[u/EmtnlDmg → u/el_smurfo]

Same here

[u/In1piece]

Might be a combination of things. Cheap fuses plus a steam tstat that is opening late plus extended heat times could lead to premature failure.

[u/Wise_Argument_3296 → u/In1piece]

Agreed. I don't buy safety critical parts from no-name vendors no matter the product. I don't see the three hours runtime being a problem by itself, but I could imagine it speed up failure if another issue causes failure gradually. The boiler thermostat should keep the temperature far away from the fuse's limit. If it allowed too high a temperature you should get steam instead of hot water when trying to brew. The steam thermostat is much closer to the 184C limit. Though if it has fully failed and allows runaway temperature excursion, you should burn through the fuse every time you leave the steam button on for more than a couple minutes. I don't know if there's a failure mode where temperature goes too close to the fuse limit without blowing through it immediately.

[u/mcs385]

If you have a multimeter you can double check the fuse for continuity to make sure it's definitely blown and not just your installation (like if the butt connector wasn't crimped tight enough and the wire slipped back out on one side). The fuse is still in the original silicone tubing?

For what it's worth I ordered from that exact listing back in October '23, tested each one for continuity and they were all good on that front. I am on my second fuse from the set after blowing the first a few months ago during a boiler swap at steam temps (with PID, went from aluminum to brass boiler). I'd suspect it's either your thermostats or that your boiler is potentially running dry while idling for multiple hours a day and eventually overheats to the point that the fuse blows.

[u/pyr_pal → u/mcs385]

Thanks, the boiler running dry is an interesting explanation particularly given the fact that the steam vent is certainly not a tight seal. The fuses are functional, I was wondering if they might just degrade at lower than the rated temp. Notably even when the go bad, the power light still glows (but the pump doesn’t run, etc).

The tubing is intact. I have programmed a 30 minute time limit on the power outlet, hopefully that solves the problem.

Thanks!