The Westinghouse 476 / 650 wall oven was the only gas wall oven you could get in Australia for a few years (a few years ago Harvey Norman started importing Belling ovens from England). The Westinghouse oven has a common fault with a noisy canopy fan (not the recirculating fan you can see when you open the oven door) where the fan becomes noisy and after some time, the fan stops turning. When the fan stops turning, the burner flame starves of oxygen and the oven fails to run.
This oven also has two different ignition problems. The ignition problems and the noisy fan problem are relatively easily fixed. One of the ignition problems will cost you nothing to fix, but the other ignition problem requires a part. Westinghouse 476 / 650 ignition problems.
Westinghouse improved the fan assembly in later model ovens but evidently, the new fan assembly will still become noisy after a few years of heavy use. If you have one of these ovens with a noisy or dead fan, don’t replace the whole oven – buy a new canopy fan and replace that for a fraction of the cost of a new oven.