I just replaced the serpentine belt on my ISL 400 and bypassed the the compressor (until my new one comes in). On mine, it is one belt for drive everything. It is long enough to work around the fan. I did have to replace the bearing on the fan hub and I replaced the fan with a Source Engineering version, much quieter now. Once the fan hub was loose, it was much easier to work around. Did most of the job through the floor in the closet. If yours is similar, it can be done but is very awkward.