| Suppose the illustrated pneumatically-operated diaphragm-actuated control valve is used to control the fuel oil outlet temperature of a steam-heated heavy fuel oil heater by controlling the steam flow. What would be the result if the stem packing was over-tightened and the stem was unable to vertically move in either direction? Illustration GS-0051 |
| A) The valve would fail in the fully-closed position, most likely resulting in a low fuel oil temperature alarm condition. |
| B) It is not possible to predict how the valve would respond to over-tightened valve stem packing. |
| C) The valve will lose control of the fuel oil temperature with the result that the fuel temperature will fluctuate with changes in fuel demand. |
| D) The valve would fail in the fully-open position, most likely resulting in a high fuel oil temperature alarm condition. |
