The 354081 is the replacement sensor probe only

A veteran technician knows that a cracked or fouled ignitor is the most common cause of "no-heat" calls

This keeps the connection cool and extends the service life of the restring kit

Its rugged construction ensures the York temperature probe resists vibration and thermal stress within high-velocity air streams

A failed switch will often remain open even after the system has cooled

Lochinvar & A.O. Smith 100109724 Valve 318820-201 The 354081 is the replacementThe Lochinvar & A. O. Smith 100109724 Valve is a direct fit OEM replacement gas control designed specifically for high efficiency water heaters and residential power vent boiler systems. This natural gas valve operates on a 20V ignition circuit, featuring a 1 2" NPT inlet and a factory set 4" WC manifold pressure to ensure precise fuel to air ratios and stable combustion cycles. Engineering specifications for the 100109724 include a 1 1 4" shank