Fire Fighting · 5 min read
Fire pump fails to start on pressure drop: weekly test failures explained
By Engr. Muhammad Aalam
Manager Utilities, Ismail Resin · Industrial utilities engineer
Why weekly tests matter
A fire pump may sit idle for months. Standards such as NFPA 25 require regular churn tests precisely because idle equipment fails silently. The pump must start automatically when system pressure falls below its cut-in setting, with the jockey pump starting first to cover small leaks.
Electric pump checks
- Pressure switch or transducer sensing line blocked or valve closed
- Controller left in manual or off after maintenance
- Phase failure or reversal relay tripped
- Cut-in setpoints set too close to the jockey pump
Diesel pump checks
- Batteries weak — check both sets and the charger
- Fuel tank below two-thirds or fuel valve closed
- Air in the fuel line after a filter change
- Starter solenoid or cranking contacts corroded
- Coolant heater failed causing hard cold starts
Good practice
Record start pressure, run time, suction and discharge pressures and any packing leakage on every test. Trends reveal problems before a real fire does.
This guidance is general. Always follow the equipment manufacturer's manual and your site safety procedures. See our engineering disclaimer.