Electric Fan Heater Thermal Cut Off

[koopsears]

I bought an electric fan heater (stove style) from an auction, and it's brand new but has a fault where the thermal cut off kicks in as soon as the heating elements get current applied to them. I've checked the PCB and all terminals and can't see any signs of blackened cables caused by overheating or a short, and I'm wondering if it's the thermal cut off fuse or the heating elements themselves (there are 3 x of them).

The heater itself is £150 RRP but I only paid £10 at the auctions so I'm not overly bothered if it's knackered, but I suspect it's a simple fault that can be repaired. Not sure if you can help, but any advice would be greatly appreciated.

 

[koopsears]

The fan itself works fine and spins up, and the housing at the back has the heating elements in it.

 

[koopsears]

And it has three heating elements.

 

[koopsears]

My first thought is to get a multimeter onto the elements, but also wondering if it could be a fuse or issue with the PCB?

 

[koopsears]

Many thanks for any advice.

 

[James]

One of the heating elements seems to have moved, I would get the mounting sorted correctly and maybe remove all 3 elements.
See if the thermal trip goes when no elements are drawing power.
If it doesn’t trip, try 1 element at a time.

 

[koopsears]

One of the heating elements seems to have moved, I would get the mounting sorted correctly and maybe remove all 3 elements.
See if the thermal trip goes when no elements are drawing power.
If it doesn’t trip, try 1 element at a time.

Thanks James - they have moved slightly as I removed the side of the housing - I'll reconnect that and try it.

 

[Avo Mk8]

Just how quickly does the thermal cutout kick-in? I'm curious because if it was working normally it would require the ambient temp (eg of the metal it's mounted on) to be up to ~150 degC before it triggers. I just wonder if it's working properly. There's a part number on it, so you might be able to find an identical replacement.

The other safety thing is that the live feed to the heating elements seems to be exposed (ringed below on the right) - the crimped 'top hat' insulator has come off! This needs sorting!