Sawdustguy
Well-Known Member
Never saw this thread before lehr brought it to the top. Here is how I handle it.
these are vacuum breakers, mounted on each side of the pump. They contain floats that rise when liquid enters and seals the valve. With air present they fall and allow liquid head pressure to purge the air and then reseal. The NPT port has a bubble breaker to prevent surface tension of the liquid from blocking the port. I have one on the inlet of each pump to allow priming when the pump cavity is full but the line is empty, and one on the outlet of each pump so when the pump is turned off air that is trapped in the outlet lines or valves cant flow back to the pump and vapor lock the pump. I have yet to brew with it but have done 3 brew temp wet runs with 100% success. The red button is for the automatic purging and the black button allows you to manually purge.
link to the duovent. Auto Dual Air Vent,Hot And Cold,1/4 In - Vent Valves - Valves - Plumbing : Grainger Industrial Supply
Damn, it's my own fault. I wish I would have seen this post a week ago. I finished the plumbing on my brewery last week.