165° C (329° F) High limit resettable thermostat cuts power to the element when it senses the unit over-heating. The M4 stud threads into the front of the boiler. These are rated at 1,000 expected electrical cycles.
EXTREME care should be taken when installing this part, as the stud has the potential to break off inside the boiler if over-tightened. It may or may not thread all the way in flush to the boiler, and it doesn't need to: slightly over hand-tight will be sufficient.
Thermal paste (or "grease") aids heat transfer between the switch and contact surface by filling in microscopic imperfections in the metal surfaces. It is especially useful for pipe mount applications.
A key characteristic of this synthetic thermal grease is it's long-term material stability. That means it won't harden, dry out, or melt in normal industrial use.
Smear some paste on the sensing head of the thermostat switch prior to bolting or clamping down. (Not to be used as a glue.)
Suitable Replacement Cross-references:
WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.