Existing Copper Pipe and Gasket Failure Due to R32 High-Pressure Incompatibility

Question

Accepted Answer

R32 max operating high pressure 3.6–3.8 MPa. Check: exceeds existing R410A copper piping design pressure (3.0 MPa) What to do: Replace with high-pressure copper tubing for R32: wall thickness per ASTM B280, OD 1/4\" → t ≥0.76 mm, design pressure ≥4.5 MPa R410A-spec gaskets (NBR, neoprene) harden and crack under R32 high temperature and pressure environment. Check: Inspect with instruments or visually What to do: Replace all gaskets and O-rings with R32-compatible material (EPDM or FKM recommended, NBR prohibited) Flare connections suffer fatigue fracture from R32 vibration and pressure cycling (flare angle 45° vs recommended 36–40°). Check: Inspect with instruments or visually What to do: Redo all flare connections: verify flare angle 36–40°, use imperial flare tool Existing piping and fittings reused without spec review during retrofit. Check: Inspect with instruments or visually What to do: Re-check pipe support clamp spacing (fix every ≤1.5 m on horizontal runs, apply vibration dampening) Repeated pressure cycling during long-term operation propagates cracks at weak points. Check: Inspect with instruments or visually What to do: After conversion, perform 3.6 MPa leak test with 30-minute hold — confirm zero pressure change before charging

Existing Copper Pipe and Gasket Failure Due to R32 High-Pressure Incompatibility

Likely causes

R32 max operating high pressure 3.6–3.8 MPa

R410A-spec gaskets (NBR, neoprene) harden and crack under R32 high temperature and pressure environment

Flare connections suffer fatigue fracture from R32 vibration and pressure cycling (flare angle 45° vs recommended 36–40°)

Existing piping and fittings reused without spec review during retrofit

Repeated pressure cycling during long-term operation propagates cracks at weak points

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