Isolating valve

Can anyone tell me what the isolating valve switchdoes in the mig-15? Ive searched all available english documentation about the mig but couldnt find my answer.

Try to check that video, it might give you the right answer:

If you switch it on, you will notice, that the engine accellerates faster, but also the danger of compressor stall and flameout increases. I'd think this is more a emergency switch(like the emergency fuel in the Sabre), but can be useful in certain situations where you need fast engine accelleration.

Fox

Thanks FoxRomeo

Pedro: I watched all tge test flight videos but i dont remember seeing anything about the isolation valve.