Fixing Rapid Pump Cycling (Short Cycling)

Why the Pump Cycles Every Few Seconds

Rapid on/off cycling (under 4 seconds) almost always points to a waterlogged pressure tank. The tank's air cushion is gone, so the pump has no buffer and hits the pressure switch cut-out almost instantly.

Two Tank Types, Two Fixes

Bladder Tank (Pre-charged)

The internal bladder has ruptured. Replace the entire tank—bladders are not field-repairable.

Conventional Air-over-Water Tank

The tank is waterlogged. Drain it completely:

1. Shut off the pump power.
2. Close the valve between pump and tank.
3. Open a drain valve on the tank (or a hose bib downstream) and vent the tank to let air in.
4. Allow all water to drain out.
5. Close the drain, reopen the pump-to-tank valve, and restart the pump.

Verify the Fix

After draining or replacing, the pump should run for at least 1–2 minutes per cycle. If short cycling persists, check the pressure switch settings and ensure the gauge reads correctly.