Over time and with frequent use, you may begin to notice problems developing with your vacuum generator switch. If your generator or VHT will not switch off, yet you have good vacuum within your toilet, the vacuum switch assembly is likely to blame. This vacuum switch is designed to serve as a replacement for Original VG3(Low profile), VHT 12, 4500 Series, and Sailvac 5200. This is the proper switch for low-profile Vacuum generators round in FLEETWOOD RVs. Generally, the life expectancy of a vacuum switch is 10-12 years. All switches are factory preset and not field adjustable. Included with this item is the 1.5″ Uniseal. The new uniseal can be difficult to install, we recommend heating the new seal with a hairdryer or heat gun and silicone lube. Repair your Vacuflush system with a new vacuum switch assembly.