Australian Pipeline Valve - Installation, Operation and Maintenance Manual 19 API6D THROUGH CONDUIT EXPANDING GATE VALVE - AP400-405 SERIES 8.3.2 To protect the seats, ensure the slab is above the closed position prior to actuation installation. 8.4 TROUBLE SHOOTING GUIDE 8.5 BODY BLEED PROCEDURE Whilst through conduit valves are block & bleed capable, the valve needs to be ordered and tested as a block & bleed valve. A special bleed system should be specifically plumbed as per diagram below. This characteristic is used to: a- Ensure that the seats are providing an effective seal, or b- Drain or flush the body cavity of an in-service gate valve. Problem Possible Reason Action Difficult to OPEN or CLOSE Valve has not been opened or closed for a long time, the seats and gate tied tightly OPEN and CLOSE the valve rapidly several times till the gate is loosened, then OPEN or CLOSE the valve to the required position Dry stem Inject lubricant as necessary Medium frozen in the cavity Heating Pipeline distorted Eliminate the distorting restriction of pipeline The gate will not CLOSE Medium frozen in the bottom Heating Debris obstruction in bottom of valve Remove debris through bottom drain plug Sealing incompletely to upstream and downstream (the pressure in middle cavity cannot relieve to low pressure) The gate is not CLOSED completely CLOSE the valve Damage to sealing surface Replace the damaged sealing element Damage to O-ring Replace O-ring Stem packing leakage Damage to packing Inject stem packing Imbalance of operation Dry bearing Inject the distorting as necessary Possible damage to drive nut or bearing Replace the damaged parts Leakage in bonnet flange Bonnet bolts loose Tighten bonnet bolts as necessary Damage to gasket Replace the gasket Leakage in grease injection and waste valve Damages to ball, spring and sealing ring Replace the damaged components Screw cap is not tight Tighten screw cap as necessary Note To relieve pressure from the internal cavity (body) of the valve while under pressure, please follow this procedure carefully. Operate the valve into the full torqued CLOSED position. Note If actuation is to be installed after shipment from APV, IT IS CRITICAL THAT THE SLAB DOES NOT DROP TO THE BOTTOM OF THE VALVE DURING ACTUATION INSTALLATION! THIS MAY RESULT IN SEAT DAMAGE.