Spooler Unit

Common issues

• Pallet/disc sticking from product residue, polymerisation or corrosion, causing high lifting pressure or failure to reseat
• Ice formation in cold climates preventing correct opening/closing
• Weather/flame screen blockage from fouling
• Seal/elastomer degradation from cargo vapour exposure causing leakage below set pressure
• Corrosion of the valve body or seat on corrosive/chemical cargo service
• Set-pressure drift from spring relaxation or fouling under the pallet

Inspection checklist

• Function test the manual lifting/test lever where fitted, without full removal
• Check for external leakage or frosting at the valve seat indicating passing
• Visually inspect the weather screen/flame arrester for fouling
• Inspect seat and pallet for pitting, corrosion or product deposit at tank entry/overhaul
• Confirm set pressure against the nameplate and last workshop test certificate
• Verify drain holes are clear to avoid liquid accumulation on the pallet
• Confirm the valve is free to move (no paint-over or corrosion seizure)
• Check the gasket/seal condition at the valve-to-tank flange

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Pallet/disc seal or seat insert
• Body O-rings/gaskets
• Spring set (renew as a matched set, not individually)
• Flame screen/weather screen mesh

Safety

• A stuck-closed PV valve can cause tank overpressure or vacuum collapse - never disable or block a PV valve
• Vented cargo vapours may be flammable or toxic - avoid standing in the vent path during testing
• Set pressure may only be adjusted by authorised personnel against the approved certificate - tampering risks tank structural damage
• Ice-bound valves must be cleared by approved methods, not force, to avoid seat damage

Class survey

The bezeichnung 'Spooler Unit' filed under 'PV Valve' suggests this record may reference a specific trim/component of a wider valve range rather than a standalone complete valve; content here is written to the general product - a tank pressure/vacuum relief valve for cargo tank venting. PV valves are typically required to carry a workshop set-pressure test certificate, reviewed at survey, with re-test intervals set by class/flag and, on tankers/gas or chemical carriers, requirements under the IGC/IBC Code venting provisions where applicable.