What to check if there is no system circulation

If there is no system circulation on a Grant Solar Thermal System, heating engineers should check for the following:

• Check whether the pump is operating or not (please refer to the manual for the Grant Solar Thermal Pump Station for support here)
• If the pump is noisy, this may suggest that there is air in the system
• Check whether the pump may be air locked and needs venting - let the pump run and the pump vents itself over time
• Check if the valves are closed - ensure that the Flow and Return valves are fully open. If filling or flushing the system, ensure the Filling/Shut off valves are fully open.