NTI No Heat to Emitters / Circulation Problem

Radiators or in‑floor loops are not heating even though boiler appears to run

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

Failed system pump, Closed zone valves, Airlock in distribution piping, Clogged system filter or strainer

Safety: Pipes may be hot; use caution when touching.

Check pump: Feel and listen for operation of the NTI primary and secondary pumps. If silent and cool, test and replace as needed.
Zone valves: Verify zone valves are opening when there is a call for heat. Manually open to test flow.
Bleed air: Use purge valves and radiator vents to remove air from each loop.
Clean strainers: Remove and clean any Y‑strainers or magnetic filters in the system piping.

Medium 3/5

System Circulation Pump

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