Does anyone know if the Durst 138 external fan blows air into the lamp housing (what I'm assuming), or sucks air out? I need a fan for mine, and I found the vacuum pump for a vacuum easel I have fits in the port, but it only sucks air out. I don't want to over heat the chamber. Since the only bulb I have is 500 watts, I need some fan solution. I could also hook up a small shop vac exhaust port to the enlarger, but then I would lose the use of the shop vac (and I need to clean it). Also, if anyone has a Durst LaFan for sale that would be even better.