Depending on the grade of PEEK you have, you will be able to print with this machine. It's just case of whether you can control crystallinity during the process.For a "low" temp system which is what you have, you will need a very good support material for adhesion and good cooling to quench the PEEK so you print it amorphous. Then you will need to anneal the final sample to achieve crystallinity and mechanical properties associated with PEEK.
Google 3DGEnce and their materials section. The ESM-10 works great as a PEEK support and the PEEK filament is of a low enough molecular weight and crystalisation time to work with this method.
"High" temp systems allow standard grades of PEEK to crystallise during the process, hence their heated chambers are above the Tg of the material.Alternatively look at Lehman and Voss, Luvocom PEEK. It's modified with additives to make it low warp so is much more forgiving.

Hope that helps.