Spanish to English Tech/Engineering Energy / Power Generation valves

Spain: HAZOP report item:
NODO: tubo absorbente (colector)
DESVIACIÓN: MÁS temperatura
POSIBLE CAUSA: bloqueo manual de las válvulas

I understand "posición de bloqueo" for valves (fail open, fail closed, fail indeterminate, and all that). So does this mean a human has manually "failed" the valve (i.e., put the valve to its "fail" position)? And if so, how is that expressed in English? Or does it mean something else... ? Thanks!