The LO sump pump relief system uses how many relief valves and what is the lift setting?

• A. Two relief valves; lift at 140 PSIG
• B. Three relief valves; lift at 120 PSIG
• C. Four relief valves; lift at 110 PSIG
• D. Three relief valves; lift at 100 PSIG

Answer: (B)

In a sump pump relief system, the job of the relief valves is to vent oil and keep the sump pressure from climbing too high. Using three relief valves provides redundancy and sufficient flow capacity so that if one valve is out of service, the others can still relieve pressure without letting it exceed safe limits. The lift setting, which is the pressure at which the valve opens, is chosen to balance normal operation against the risk of overpressure. A lift of 120 PSIG means the valves start to open when the sump pressure reaches 120 PSIG, keeping the system within a safe range without venting too early or too late. This combination—three valves with a 120 PSIG opening pressure—supports reliable protection and predictable relief behavior, whereas configurations with fewer or more valves or with different set pressures would either reduce redundancy or allow undesirable pressure fluctuations.