I tried to help with this question earlier today... I said this...
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They have a switch built into the circuitry - a thermostatic switch nearly always with a tell-tale neon light - orange...
As it warms up the switch is closed and the light is on - then when it gets up to temperature the thermostatic switch opens - heating stops - the light goes out - things begin to cool down. Then the switch closes and it all starts over again.
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Clearly this answer is of no help to you - sorry
Perhaps if you define what you mean by "a while" things might be clearer. Switches on OK - Steams OK and goes off for an unspecified period - a minute - five minutes? How long?
Do say, October 2014
