How to properly replace a liquid level sensor probe?

1.  Remove your old sensor probe by loosing the boiler nut. NOT THE PROBE NUT!

2.  Measure the length of the new probe against the old probe. They may vary in length as much as an inch, which is not a problem. What is important is how much of the probe is inserted into the boiler. If it is not enough, your boiler will be too full which will result in two things: Very wet steam and not much of it. If it is too low, you can burn out your heater. Simply make a mark with a Sharpe pen on the sensor probe itself for a reference. If the new probe is longer, it is OK to trim it too if you like.

3.  Wrap a couple of turns of Teflon tape around the male threads of the boiler nut.

4.  Thread the boiler nut securely into the boiler, not too tight and don't snap it off.

5.  Drop the rest of the assembly, as shown in the image, down through the center of the boiler nut.

6.  Snug up the probe nut. Note: Snug up the nut, DO NOT over tighten. If you over tighten, you will crack the Teflon sleeve and the probe will sense ground all the time, resulting in your machine not calling for water. All you want to do is snug it up so it holds the probe at the proper height and there is no steam leaking around it when you pressurize your boiler.