Oven selector switch query

[DJAndy]

Does anyone fault find appliances?

The element in a fan oven was >500Ω so I replaced it, still no heat.

Got the back off and my multimeter on it for a bit of disconnected dead testing:
thermostat <1Ω
overheat cut out <1Ω
selector switch - grill element, light, & fan connections all <1Ω
fan element ~48Ω

So am I right in thinking I need a new selector switch?

 

[telectrix]

a bit of careful live testing next. trace the voltage from the incoming down to the element. a voltstick would be handy as a first check as it's no contact with live parts (safer, but not entirely reliableas can pick up from other wires).

 

[DJAndy]

I'm not on site, my results from previous visit with 2 probe tester are:

Thermostat set to off
Fan element L to supply N, ~230v AC
Fan element L to supply E, ~230v AC
Fan element L to element N, continuity

Thermostat set to on
Fan element L to supply N, ~48v AC
Fan element L to supply E, ~48v AC
Fan element L to element N, continuity

Same tests on grill element, Thermostat set to on
Grill element L to element N, ~230v

Connect the grill element feed to the fan element and selector to 'grill' - the fan element heats.

 

[James]

Looks like you have correctly diagnosed a faulty switch.

 

[DJAndy]

Thanks both, I've convinced myself that the switch is faulty and have ordered another.

What threw me was the odd readings when the thermostat was changed.

 

[telectrix]

sounds like voltage is dropping under load due to poor connection, quite probably the switch.