Water Leaking Out Your Backwash Line? Your Hayward Spider Gasket Is Probably Shot (SPX0710XD)
Water dripping out of the backwash line is one of the most common complaints we hear at the counter. The valve handle is set to Filter, nothing should be going to waste, and yet there is a steady trickle heading down the drain. The good news is that the valve itself is usually fine. The real culprit is a small rubber part inside it called the spider gasket, and on Hayward Vari-Flo valves the replacement part is the Hayward SPX0710XD.
This guide walks through how to confirm the gasket is your problem, how to fix it, and when it makes more sense to just replace the whole valve.
Why is water coming out of my backwash line?
A worn or warped spider gasket is the most common reason water leaks out of the backwash line while the valve is set to Filter. The gasket seals off each port inside the valve, so when it wears down, water sneaks past into ports that should be closed.
Pop the lid off any multiport valve and you will find a round rubber gasket shaped like a wagon wheel. The spokes are why everyone calls it a spider gasket. When you push the handle down and turn it, the diverter presses against those spokes to seal off the ports you are not using. Years of chlorine, heat, pressure, and (the big one) turning the handle while the pump is still running will flatten or tear those spokes. Once that happens, the seal is gone and water finds its way to waste.
How to tell if your SPX0710XD gasket is worn out
You can usually confirm a bad spider gasket without taking anything apart, just by watching where water goes. If you want to be certain, pull the valve lid and look at the gasket directly.
- There is a constant trickle out of the backwash or waste line while the valve is on Filter.
- Water blows back into the pool through the returns while you are on Backwash.
- The gasket looks flattened, grooved, or chewed up, or a spoke has lifted out of its channel.
- You find small bits of black rubber in the pump basket. That is often the gasket breaking apart.
Any one of these is enough reason to swap the gasket. Running the valve with a bad seal wastes water constantly and makes backwashing less effective, so it is not a problem that fixes itself.
How to fix it: replacing the spider gasket step by step
Replacing a spider gasket is about an hour of work with basic hand tools. Here is the short version of how to do it.
- Shut the pump off. Never move a multiport handle while the pump is running.
- Remove the screws around the valve lid and lift the whole lid and rotor assembly out.
- Peel the old gasket out of its channel. Take a photo first so you can match the orientation.
- Clean the channel completely. Old rubber and debris left behind will keep the new gasket from seating flat.
- Press the new SPX0710XD gasket into the channel, spoke by spoke, until it sits evenly all the way around.
- Reassemble the lid and tighten the screws in a criss-cross pattern, a little at a time. Snug is enough. Overtightening warps the lid.
- Turn the pump back on in Filter, then test Backwash and Rinse and watch the waste line.
One caution before you order: the SPX0710XD fits select Hayward Vari-Flo multiport valves, so check your valve model number (it is molded into the valve body or lid) to make sure this gasket is compatible with your unit.
Should you replace the gasket or the whole valve?
If the valve body and lid are in good shape, replace the gasket and move on. A new gasket restores the seal and the rest of the valve has no other wear parts that commonly fail.
Replace the entire valve instead if the lid is cracked, the handle assembly is wobbly or stripped, or the gasket channel itself is damaged. A new gasket cannot seal against a warped or gouged surface, and you will be right back where you started in a season. We carry complete Vari-Flo valves too if that turns out to be your situation.
Making your new SPX0710XD last longer
The single best habit is simple: always shut the pump off before you move the handle, and always press the handle fully down before rotating it. Turning the valve under pressure grinds the diverter across the spokes and is the number one thing that kills these gaskets early.
Beyond that, a light coat of pool-safe silicone lubricant on the gasket during installation helps it seat and move smoothly, and draining the valve properly before winter keeps trapped water from damaging the rubber in a freeze. Do those things and a Hayward SPX0710XD spider gasket should give you years of drip-free service.
Hayward | SPX0710XD | Vari-Flo Multiport Valve Gasket | Replacement Spider Gasket
$739.20
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