Hi TFP; I am new owner of ~20k pool with hayward main pump and a polaris cleaner w/pb4 booster. The Polaris booster was working fine the other day, the cleaner moving quickly about the bottom of the pool. However, when I turned it on today it was noisy and the cleaner did not have much pressure, moved really slow. The pool is spotless, nor cal summer, and I am wondering what may have happened to the polaris booster. There are two timers, one for main and one for booster, and I am thinking the booster may have been running without the main pump on. As a result, this may have burned up the booster? Not sure, hoping someone can guide me a little as what to look for on this pb4 booster. Many thanks!