All symptoms
Diagnosis

FLAT / UNDER-CARBONATED

Beer pours clear with little head and tastes lifeless.

3

LIKELY CAUSES — RANKED MOST COMMON FIRST

  1. 1

    CO₂ PRESSURE TOO LOW

    Beer slowly loses CO₂ until equilibrium with applied pressure.

    Fix
    • Set regulator to the brewer's spec for current keg temp.
    • Allow 24–48 hrs for carbonation to recover after re-pressurizing.
  2. 2

    EMPTY / LEAKING CO₂

    Tank empty or a leak in the gas line.

    Fix
    • Soap-test all gas fittings; replace bad washers or hose clamps.
    • Keep a spare full CO₂ cylinder on site.
  3. 3

    OLD KEG / PAST FRESHNESS DATE

    Beer staled and CO₂ absorbed into headspace gases.

    Fix
    • Rotate stock FIFO; pull kegs past the brewer's freshness window.

STILL NOT FIXED?

Capture temp at the faucet, applied PSI at the regulator, and a photo of the pour. Then check the spec reference or run a full line cleaning.