Thanks it appears the 1/2" acme cap on my vacuum pump is not sealing.I put the “vacuum” (I’m assuming micron gauge) on one valve of a recovery tank. I connect my hose from a vacuum pump to the other valve. Pull a vacuum, and watch the gauge. This set up tests the hoses, micron gauge, and pump.
Most residential units use 1/4 SAE flared fittings and some mini splits now use 5/16 SAEI am in need of a 1/4 inch flare union to test my CPS vacuum gauge and hose but not sure if the unions sold at the big box stores are the same as refrigerant unions. Are they the same or different??
Are you sure its acme? Most pumps are SAE flared, at least every single one I have used, mostly JB.Thanks it appears the 1/2" acme cap on my vacuum pump is not sealing.