and 126# for water

slip-free interface with the drive shaft

Common Questions: Which valve series does this bonnet fit

System Reliability: Eliminates "Pressure Switch Stuck Open" or "Failed to Close" fault codes common in high altitude HVAC installations

This extends the service life of internal electronic components and reduces the strain on the 24V secondary transformer

AERCO GP-18900 Seal 320734-701 and 126# for waterThe AERCO GP 18900 Seal is a critical genuine OEM replacement part specifically engineered for high performance AERCO boiler parts and commercial water heating systems. This precise manifold to lower head seal is designed to create a robust, leak proof interface between the manifold and the lower head assembly, ensuring pressure integrity and thermal efficiency. As an authentic HVAC replacement seal, the GP 18900 prevents bypass leakage and maintains