Description

The Hayward SP1056 is a 1-1/2 inch hydrostatic relief valve, the genuine Hayward part. It is a small fitting with one job that only matters at one moment, and at that moment it matters a great deal.

The problem it solves

A full pool is heavy enough to hold itself down against the water in the ground around it. Drain the pool and that balance is gone. If the surrounding ground water has nowhere to go, it presses on the underside of the shell. The hydrostatic relief valve gives it a way in, so the pressure equalizes through the floor instead of working against it.

Where it lives

The valve sits in the main drain sump at the deepest point of the pool. It is passive: it opens on pressure difference and reseats on its own, with nothing to power, set or maintain.

When to replace it

Because it does nothing at all during normal operation, a failed hydrostatic valve gives no warning. If the pool is coming down for a liner change, a replaster or a repair, check the valve while the floor is accessible and fit a new one if there is any doubt.