When we tried to use our 240V wall-mount electric space heater in the master bathroom, we found that it wasn't working correctly.  It would run a couple minutes at most and then shut off.  When we tested it after the electrical workers installed it, we just verified that it would run but never left it on for more that 30 seconds.  
During construction, the electricians originally ran 120V to the heater and we had to make them change the circuit to 240V.  After finding out the heater wasn't working, I started wondering if the heater did not get wired correctly so I checked the wiring both in the electrical panel and in the heater's wall box to make sure they matched the manufacturer's instructions.  
When I took the heater out of the wall, I noticed that some of the heating coils were bent and were touching each other.  Thus I got a pair of tweasers and bent the heating coils so they didn't touch each other.  After putting the heater back together, it ran for 20 minutes before I turned it off.  So it appears the problem has been fixed.
That heater sure makes the bathroom toasty in no time.  If I had it to do over again, I would have located the bathroom HVAC register somewhere other than right below the wall heater.  Having warm air flow through the register right below the heater might give the wall heater false temperature readings.  We'll have to see how much the register affects the wall heater.  But for now I'm just glad we got the wall heater working.