Raypak Flow Imbalance / Primary-Secondary Piping Issue

Boiler cycles on and off due to low flow; piping near boiler is very hot but distant zones are cold.

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

Incorrect pump sizing, Closed or partially closed valves, Air-locked secondary circuits, Plugged strainers near Raypak boiler

Safety: Allow system to cool before opening vents or strainers.

Steps:

Verify all isolation and balancing valves are open to zones that are not heating.
Bleed air from high points and radiators.
Clean strainers in the boiler loop and secondary circuits.

Persistent flow issues may require a system design review by a hydronic specialist.

Medium 3/5

System Circulator Pump

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