Steam Boiler Heat Sensor R&R
Thanks to RobertD for documenting his replacement of the steam boiler heating sensor below:
- Be sure you have called tech support where you purchased your S1, validated that this is the suspected issue and have a replacement heat sensor in hand (see photo 4 below) before proceeding.
- Materials needed:
- Replacement heat sensor
- Phillips screwdriver
- One nylon cable tie
- Tube of clear silicon rubber
- Turn off the S1, unplug it, and let it cool down completely.
- This repair can me made with only the top cover removed. However, if after removing the top cover, it feels too cramped for you, remove the remaining covers. If you don't already know how to do this, see the S1 Photos page.
- Review the photo below (looking from the back side of the S1 down on top of the steam boiler) in order to get your bearings.
- In the lower right corner of the photo below you see a wire bundle which comes from the control board. The red wire goes to connector B which is the water level sensor. One black and one brown wire go through orange insulator sleeves C. merge as two black wires, and then go down into the brass fitting shown as A. This is the temperature sensor. Thanks to the wonders of fine Italian espresso craftsmanship, your wire colors can - and will - vary! Lastly there is an orange wire that connects to the ground screw in the middle bottom of the photo.
- The first step is to remove the old sensor by pulling straight up on the two wires that go down into the hole at location A. This hole is sealed with a small plug of clear silicon rubber so it might take some tugging to remove it. No need to worry about damaging these wires or the attached sensor since you will be inserting a new one anyway.
Below is a close-up of the insulating sleeves and nylon cable tie previously shown above. Carefully clip off the nylon cable tie and then slide down the orange insulating sleeves to expose the spade lug connectors inside. The sleeves are pretty snug so it may take a little effort to slide them off.
With the sleeves removed, disconnect the spade lug connectors. They're pretty tight. Take care not to damage the connectors.
The photo below shows the new sensor. Reconnect the spade lugs on the new sensor to the ones on the S1 cable. It doesn't matter which wire connects to the other. Then slide the orange sleeves back over these connectors and secure with a new nylon cable tie.
Slide the new sensor down into the opening until in bottoms out. Put a small dab of silicon rubber into tube opening to seal it up. This is just to keep debris and water from getting down into the tube. Screw the top cover back on and you're done.
The photo below has nothing to do with the above repair. However, directly behind the silver water sensor and in front of the copper heat element in this photo, you can see the copper tube which the heat sensor slides down into. This will give an idea about how far the sensor should slide down into the hole before it bottoms out.