Polaris "Trade Grade" TR36P Pressure Cleaner In-Line Back-up Valve, Black (9-100-1201)
This back-up valve was designed to be the feature that backs the pressure side cleaner out of any corners or edges along with the pool steps which would cause the cleaner to be hung up or impeded in any way. Without it, the cleaner would be insufficient in its abilities to suck and pull up dirt and debris off your pool's surface.
This part is black and should be located approximately 18 inches from the head of the cleaner and will turn on every 2 ½ to 3 minutes to pull the cleaner out of tight corners or trouble spots.
Great troubleshooting tip, if the cleaner is tangled up via the hoses or floating at the top of the pool water, would be to check this back-up valve. You can do this by pulling it out of the water to see if its running, it should run for approximately 30 seconds. If it runs longer than this then it means the internal mechanism has failed and is stuck in the open position ultimately meaning it needs to be replaced. just make sure you are purchasing the full assembly with the mechanism included, replacing just the outer case will not correct this issue. The mechanism can be purchased here on our site.