Protherm No Circulation in Hydronic Loop

Radiators or hydronic circuits connected to Protherm furnace stay cold while furnace runs

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

Closed isolation valves near Protherm furnace, Airlock in system, Failed circulation pump, Blocked dirt separator or filter

Safety first: Allow system to cool before bleeding or opening valves.

Step 1 – Valve positions: Confirm that all isolation valves around the furnace and pump are fully open.
Step 2 – Bleed air: Bleed air from radiators and high points. Top up pressure as needed.
Step 3 – Pump check: Listen for pump operation and feel the pipes. If the pump is silent and pipes remain cold, the pump may have failed and should be replaced.
Step 4 – Clean filters: Clean any dirt separators or strainers in the return line.

Medium 3/5

Circulation Pump

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