In brief: 1.5-inch Pentair union set for SuperFlo and SuperMax pumps. Pentair part number 351157.
Leaking or seized unions
Union fittings allow you to remove the pump without cutting the plumbing. Without them, even minor maintenance becomes a major plumbing project.
They leak when the internal O-ring has hardened, or when the threaded ring has been tightened with pliers and deformed. They seize when the threads have been overtightened or become clogged.
A new union set restores the seal and provides a clean disassembly point for all future maintenance.
Official Pentair specifications
| Part number |
351157 |
| Diameter |
1.5 in |
| Application |
Pentair SuperFlo and SuperMax pumps |
| Original part |
Yes, genuine Pentair part |
Frequently asked questions
How should a union be tightened?
By hand. A pool union never needs to be tightened with pliers. The O-ring creates the seal; pliers only deform the ring.
What should I do if a union is weeping?
Turn off the pump, unscrew the union, and inspect the O-ring. A flattened or hardened O-ring should be replaced. Clean the sealing surface before reassembling.
Is Teflon tape needed on these fittings?
Not on the O-ring seat. Teflon tape should only be used on the tapered threads on the side that screws into the pump.
Service on the North Shore
Piscines Geyser keeps Pentair parts in stock in Blainville and serves the Laurentians. Send us a photo of your setup if you are unsure about compatibility: we will confirm before shipping.
