Deep Technical Chapters · Pressure Testing & Leak Diagnosis
Ghost Leaks
A suspected pressure loss that looks like a system leak but is actually caused by test equipment, access fittings, temperature, isolation, valve passing, or poor stabilisation.
A ghost leak wastes hours and destroys confidence. It appears to indicate a refrigeration-system leak but is actually caused by — or confused by — the test setup. The rule is simple: don't chase a ghost leak. Prove where the pressure is going.
What causes a ghost leak
- Test equipment (hoses, manifolds, gauges)
- Access fittings and Schrader cores
- Temperature changes
- Isolation arrangements
- A valve passing internally
- Poor stabilisation
- Incorrect test boundaries
- Other test-setup problems
Gauge / access-point ghost leak
Connecting gauges or test equipment introduces a new leak path through hoses, manifolds, Schrader fittings, core depressors, adaptors and service valves. The system appears to lose pressure, but the pressure is leaving through the equipment you attached to it.
Temperature ghost leak
Pressure changes because the nitrogen temperature changes — not because the system leaked. See the Nitrogen Temperature Effect chapter.
Investigation order
Work the causes in this order before you touch the system as a leak:
- Temperature
- Test equipment
- Access points
- Isolation arrangement
- Stabilisation
- Actual system leakage
Field Rules
- 01
"Don't chase a ghost leak. Prove where the pressure is going."
- 02
"A gauge reading tells you what happened. It doesn't tell you why."
Diagnosis at a glance
Common mistakes & callbacks
- •Assuming any pressure drop is a system leak.
- •Adding test equipment that introduces its own leak path.
- •Skipping the temperature check.
