We clear the water from your system with a high volume compressor in the proper sequence based on system design. Sustained volume at around 80psi is required to do it properly. Above 80psi may cause damage. A lack of sustained volume will not clear the lines which can lead to freeze damage. We watch for problems that will need to be addressed in the spring. Systems that are properly winterized every year require fewer repairs and last longer. Small home compressors don't have enough sustained volume to do the job right. Fly-by-night guys with a compressor may save you $20 in the fall and cost you hundreds in repairs in the spring. Call us, we are professionals.