# Gaggia Classic Dead, Suspect Steam Thermostat



## astyy (Jan 18, 2019)

Hi All

My second topic on here, my Classic (R18161/40) has been working brilliantly (since advised by MrShades to switch to bottled water). This morning I noticed the steam seemed super hot, then a short while after the machine wouldn't turn on (no LED, pump etc) for 2nd coffee 😡

I got to work with my DMM and tested no continuity across the thermal fuse on top of boiler (relating to overheating?), I can replace this but what else is likely to have gone to cause this and sensible to replace at the same time? I have continuity across both thermostats and the boiler elements, but I did note the upper thermostat (steam?), the black plastic part is loose in the brass body so I suspect this too.

Thanks for any advice and any recommendation where to source parts to support forum members would be great.


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## Blue_Cafe (Jun 22, 2020)

Dare i say from a DIYer, it sounds like the Steam (145c?) thermostat has failed closed and the thermo fuse has tripped?

Perhaps a new fuse and pair of thermostats (wouldn't replace just one tbh) might fix it.

I am sure there are more expert forummers who could help you better though.


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## MrShades (Jul 29, 2009)

If you were just using it normally - ie it wasn't switched to steam mode at the time - then BOTH the brew (on the side) and steam (on the top) stats are in the circuit.

Hence failure of the steam stat wouldn't be a huge problem unless you were steaming at the time and then left it in steam mode rather than turning off steam immediately afterwards - which allowed it to overheat whilst you were away, and the thermal fuse went.

In normal brew mode you have the brew stat and the steam stat as backup. In steam mode it's only using the steam stat - and it sounds like you were steaming at around that time, so failure of the steam stat would be a distinct possibility - and certainly my first port of call.

Swap it for a 155c one and you'll have more powerful steam in the future.

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## Blue_Cafe (Jun 22, 2020)

Swapping the steam thermostat from 145 c to 155c will raise the boiler pressure by 50% and increase wear and tear on the Steam needle valve and creates a more stressed boiler environment.

I'd leave it as is.


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## MrShades (Jul 29, 2009)

Yes, it increases the steam temp from 145 to 155 with a corresponding increase in steam pressure from about 3.1bar to 4.4bar

The Gaggia Classic optional 155c stat is available here if you're interested : https://www.theespressoshop.co.uk/Mobile/en/Gaggia-Classic-Boiler-Thermostat-155C---DM1288/m-m-3101.aspx

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## astyy (Jan 18, 2019)

Thanks I've found the parts I need on that. I'm not sure if the fuse comes with the butt connectors, if not can the fuse legs be soldered into the wiring?


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## MrShades (Jul 29, 2009)

astyy said:


> Thanks I've found the parts I need on that. I'm not sure if the fuse comes with the butt connectors, if not can the fuse legs be soldered into the wiring?


The fuse just comes bare with wires. You need some uninsulated butt connectors to crimp the wires on... solder will melt at about 180c so best avoided.

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## astyy (Jan 18, 2019)

I'm pleased to report parts arrived and fitted and morning espresso is back on the menu. I couldn't easily source the butt connectors so cut down these molex header connector crimps and joined to approx 1cm of the old fuse leg, it formed a very tight physical connection which slid back easily into the insulation tube.

Also I went for the 155 steam thermostat which certainly seems a bit pokier.

Thanks all for the advice.


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