Champlain 1-1/2" MPT x 1-1/4" S Return Fitting (ACM-991-SF) controlsystemparts When a check valve becomes

When a check valve becomes unreliable or fails to close as intended

a 2-3/8 inch hole size

clear tank lid to restore secure closure and better visibility

which can simplify replacement work and reduce the need for workaround wiring solutions

and PRB12 references

Champlain 1-1/2" MPT x 1-1/4" S Return Fitting (ACM-991-SF) controlsystemparts When a check valve becomesThe Champlain return fitting is designed for compatible pool plumbing applications where a 1 1 2 inch MPT connection needs to transition to a 1 1 4 inch slip fitting at the return point. A fitting like this is useful because it helps create the correct wall return connection while supporting a cleaner plumbing transition. This replacement is especially useful when the original return fitting is cracked, leaking, discolored, or no longer fitting