This innovative trap priming system automatically primes up to two floor drain traps using our patented water distribution system. The PRIME-RITE requires no adjustment but must be installed on a cold water line of 1 1/2" (38 mm) diameter or less. The priming valve is automatically activated when it senses a pressure drop of 10 PSIG (70 kpa). The valve's operating range is 20 to 80 PSIG (138 to 552 kpa).