Trap and Safety Drain
A safety drain is a second trap that is sized to handle the same load as the primary trap. It is located above the primary trap and discharges into a pumped return line or an open sewer. When there is sufficient differential pressure across the primary trap to operate normally, condensate drains from the drip point, through the primary trap, and up to the overhead return line. When the differential pressure is reduced to the point where the condensate cannot rise to the return, it backs up in the drip leg and enters the safety drain. The safety drain then discharges the condensate by gravity.
Installation Instructions
- A float and thermostatic trap is normally the preferred trap for a safety drain because it can handle large amounts of air.
- When installing a safety drain, ensure that the bottom of the body of the safety drain is approximately 4 inches (10.16 cm) above the top of the primary trap.
- Connect the body drain of the safety drain trap to the inlet of the primary trap. Draining the body of the safety drain prevents the loss of condensate formed by radiation when the primary trap is in operation.
- Install a vacuum breaker integral to the safety drain. The vacuum breaker will ensure proper operation even if the inlet pressure to the heat exchanger falls below atmospheric pressure. Attach a gooseneck to the vacuum breaker inlet to reduce dirt contamination.
