It is fully compatible with Johnson Controls Penn A419

Can I use this as a replacement for a single-stage valve

the fan pressure switch may be failing to engage the cooling circuit

and mounting hardware

Engineered as a direct replacement for the legacy 904407

Watts 0555180 Valve R-410A It is fully compatible withThe Watts 0555180 (Series LF600) is a high performance 2" NPT silent check valve engineered to replace the legacy 0376357 model. Constructed with a lead free cast copper silicon alloy body, this Maxi Flo bronze check valve utilizes a conical disc and PTFE seat to ensure positive shut off and mitigate the damaging effects of water hammer. For HVACR contractors managing clear water or steam applications, this valve provides a low pressure drop