Oso Hydraulic Shock / Expansion Issues

Oso water heater causes water hammer or banging noises in pipework when heating or taps are opened/closed.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Lack of expansion vessel on unvented system, Water hammer due to fast‑closing valves, Loose pipe clips, Over‑pressurized system

Safety first: Be cautious around moving or vibrating pipes; secure them before they cause damage.

Secure pipework: Add or tighten pipe clips near the Oso cylinder and along hot and cold runs.
Check expansion vessel: Verify the expansion vessel is correctly sized and charged. Replace if waterlogged.
Install water hammer arrestors: Fit arrestors near fast‑acting valves (e.g., washing machines) if hammer persists.
Verify pressure: Ensure the pressure reducing valve on the Oso inlet group is functioning and set correctly.

Medium 3/5

Oso expansion vessel

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