Fan switch fitting

[Curly]

As my fan wasn't cutting in I've ordered new radiator/thermal switch

 

The old one had a compressed copper washer - the new one from caterham came with normal flat steel (?) washer

 

I've fitted the switch with the new washer but get a small leak - any idea where I can get a compression washer to fit - local motor parts shops don't have them and I can't find anything on the Caterham store?

 

Alternatively is there any other option - gasket sealent etc etc that could be used?

 

Cheers

Curly

 

[Paul Richards]

PTFE tape?

I prefer to use an 'O' ring - make sure its a v. tight fit or it will "spread" when tightened.

[Myles]

Halfords stock felt and copper washers etc. Most of the radiator fittings I've had seem to use one or the other.

[Paul Deslandes]

the copper washers can be used again provided they're smooth and annealed. Lay a piece of fine abrasive paper on a flat surface and polish both sides of the washer. Once it looks reasonably smooth heat it up in a gas flame and either quench it in water or let it air cool. Unlike steel and most other metals, copper doesn't work harden if quenched. The soft copper will now seal properly.

In my experience the main reason these switches fail (I've had at least two go over 17 years) is that the contacts burn from arcing when the motor switches on and off. If you add a relay to the circuit to switch the motor, the problem goes away.

 

Paul

[Myles]

Relay diagrams are hosted(with permission) on my site - look for Christ W Electrickery series on the What's On This Site listing:

 

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