Peerless Water Hammer / Thermal Expansion Noise

Boiler makes loud banging or knocking noises when starting or stopping

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

Fast-closing zone valves, lack of expansion tank, improperly supported piping, high flow rates

Safety first: Be cautious around moving parts and hot pipes.

Steps:

Observe operation: Note if banging occurs when zone valves close or circulator stops.
Check expansion tank: Ensure a properly sized expansion tank is installed and charged.
Slow down valves: Replace fast-closing zone valves with slow-closing models or add water hammer arrestors.
Support piping: Add or adjust pipe hangers to prevent movement.

Medium 3/5

Expansion tank

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