Method and actuator for detecting blocking of control valve regulating flow of fluid

An HVAC actuator (1) for moving a valve member (21) of a control valve (2) to regulate a fluid flow through the control valve (2), the HVAC actuator (1) comprising a circuit (11) configured to:

• monitor a rotation angle (ϕ) associated with a drive torque (Mdrive) applied by the HVAC actuator (1) for moving the valve member (21);
• detect a blocking of the control valve (2), if the applied drive torque (Mdrive) effects a change of the rotation angle (Δϕ) which is smaller than a threshold angle (ϕth);
• upon detection of the blocking, control the HVAC actuator (1) to repeatedly change the applied drive torque (Mdrive) between a first torque value (M1) and a second torque value (M2) smaller than the first torque value (M1);
• and to
• control the HVAC actuator (1) to periodically modulate the first torque value (M1) between a third torque value (M3) and a fourth torque value (M4) smaller than the third torque value (M3).

A non-transitory computer-readable medium having stored thereon computer program code which, when executed by a circuit (11) of an HVAC actuator (1), the circuit (11) executes the steps of:

• monitoring a rotation angle (ϕ) associated with a drive torque (Mdrive) applied by the HVAC actuator (1) for moving a valve member (21) of a control valve (2);
• detecting a blocking of the control valve (2), if the applied drive torque (Mdrive) effects a change of the rotation angle (Δϕ) which is smaller than a threshold angle (ϕth);
• upon detection of the blocking, controlling the HVAC actuator (1) to repeatedly change the applied drive torque between a first torque value (M1) and a second torque value (M2) smaller than the first torque value (M1);
• and
• controlling the HVAC actuator (1) to periodically modulate the first torque value (M1) between a third torque value (M3) and a fourth torque value (M4) smaller than the third torque value (M3).