| Pop Drain | Activates to drain the system when pressure falls below 4 or 5 psig (.27 or .34 bar). It closes when pressure rises above 7 to 8 psig (.48 to .55 bar). |  | | | Thermo Drain | A valve that is operated by a bimetal strip, the thermo drain senses condensate temperature and opens when the temperature falls below approximately 165° F (74° C). A thermo drain is not recommended for service above 15 psig (1 bar). |  | |