How to Fix / Troubleshooting

Safety first: Discharged water may be hot. Keep clear of the discharge outlet.

Steps to check:

Check system pressure: Read the pressure gauge when the system is cold and hot. If pressure rises excessively when hot, the expansion vessel may be faulty.
Verify filling loop: Ensure the filling valve is fully closed and not passing water.
Recharge expansion vessel: With the system depressurized, check and recharge the vessel air side to the specified pressure.
Replace safety valve: If the valve continues to drip even at normal pressure, it may be contaminated and should be replaced.

When to call a technician: Expansion vessel and safety valve work is best handled by a heating professional.

Boiler safety valve repeatedly discharges water through the discharge pipe

Possible Causes