The standard requirement are: 22.10 It shall not be possible to reset voltage-maintained non-self-resetting thermal cut-outs by the operation of an automatic switching device incorporated within the appliance.
NOTE 1 Voltage-maintained controls will automatically reset if they become de-energized.
Non-self-resetting thermal motor protectors shall have a trip-free action unless they are voltage maintained.
NOTE 2 Trip-free is an automatic action that is independent of manipulation or position of the actuating member.
Reset buttons of non-self-resetting controls shall be located or protected so that their accidental resetting is unlikely to occur if this could result in a hazard.
NOTE 3 For example, this requirement precludes the location of reset buttons on the back of an appliance, which could result in them being reset by pushing the appliance against a wall.
Compliance is checked by inspection.
Now we are making one new room heater, it is mechanical control , and with one thermostat (adjustable) and one thermal cut-off (manual reset type ), please see enclosed file,.
Some lab engineers think this structure can not meet clause 22.10 of EN60335-1, becase thermal cut-off can reset if thermostat is open.
1) even the thermostat do not operate during abnormal operation and only thermal cut-out turn off the circuit. The thermal cut out can be reset by the automatic switch action of thermostat as the adjustable temperature range of the thermostat is 6C minimum, 75C maximum.
2) The thermostat could be automatically switch on and off by the variation of ambient temperature and not only by the heater.
My opinion are:
1st, we must consider the possibility which thermostat and thermal cuto-ff can act at same time, otherwise, it is useless.
2nd, According to one heater, when thermal cut-off is open, there have no more heat to let thermostat open.
3rd, Even if the the thermal cut-off reset, it can not result a hazard.
We would like to get your kindly comment. 623421204075082.xls
