By replacing a standard piston with this R-22 expansion valve kit

providing a 1-to-1 replacement for legacy 48M frame motors

this model is part of the VT series designed for hot and chilled water

0/50# regulator body

and UDAP series

Lochinvar & A.O. Smith 100109294 Pilot Assembly 318518-761 By replacing a standard pistonThe Lochinvar & A. O. Smith 100109294 Pilot Assembly is a precise OEM replacement engineered for Flammable Vapor (FV) ignition systems. Designed for use in Propane (LP) residential water heaters, this 160 Degree Celsius rated assembly ensures critical thermal safety by maintaining the correct ignition sequence and flame rectification. As a high performance FV Pilot Assembly, it integrates a durable thermopile or thermocouple (depending on specific