Description

The CMP 21063-160-000 is a hi-temp union assembly that threads into a 1-1/2 inch port and glues to 2 inch PVC. It is the fitting you use when the pump or filter is 1.5 inch and the plumbing around it is 2 inch, which is a very common combination on a modern system.

Why the O-ring matters

The threaded side seals on an O-ring, not on thread tape. That removes the whole ritual of wrapping, testing, unwrapping and rewrapping, and more importantly it removes the reason people overtighten. A tapered thread pulled up hard into a plastic housing is how pump and filter ports get cracked, and it is an expensive way to fix a small leak.

Hi-temp construction

The body is CPVC and PVC rather than plain PVC, so it handles the warmer water on the discharge side of a heater without going soft. The union face itself seals on a T ring.

Serviceability

The point of a union is that it comes apart. Loosen the nut and the equipment separates from the plumbing, so a pump can be pulled for a seal change or a filter opened without a saw and a bag of couplings.