The bimetal returns original contour permitting the contacts to close and restart the connection, after the thermostat had a possibility to cool. Dryer thermostats are rated. This temperature will be recognized by a L followed by the temperature rating. L130, L145, L155, etc. This is the temperature the typically closed contacts will open at. At room average temperature, when tested from the circuit, even if good, the connections will be closed and should show persistence. The contacts will stay open until it is chilled into a set temperature which is going to be dependant on the calibration once opened by heat.
This differential can also be exhibited on the part and might be 10-40 or more. Some models can have up to five, one for each one of the various temperature choices available plus the safety thermostat. Some drier thermostats are of the SPDT design and may usually be recognized by a 3rd wire terminal mounted towards the top of the thermostat housing. On this design when a set of connections opens, another set closes. This second contact is usually utilized to supply electricity to the allow the timer to advance when from a permanent press or automatic mode. There are also various multi terminal thermostats from use on some dryers. These can usually be recognized by the extra small terminals mounted flat as opposed to at the top of the housing. They may also often be distinguished by the small blobs of solder located at the base of more than one of those extra terminals. These multi terminal thermostats work comparable to either the 2 or 3 terminal models described above, but have an added internal heater, therefore the blobs of solder used to connect it to the terminals.