Hayward W3DE3620 Blowing DE Back Into the Pool? Causes and Fixes
You add your DE, walk back to the pool, and there is a cloud of white powder shooting out of the return jets. It settles on the floor and makes the water look like milk. Not a great start to the weekend.
If you run a Hayward W3DE3620, that powder is going straight through the filter instead of staying inside it. Something is letting it bypass the grids. Here is what usually causes it and how to track it down without guessing.
Why is my Hayward W3DE3620 blowing DE into the pool?
Most of the time it is a hole or a tear in one of the filter grids. A DE filter works by coating fabric grids with powder, and the powder is what actually does the filtering. If that fabric splits anywhere, the DE has a shortcut back to your pool.
The other common causes are a cracked manifold on top of the grid assembly, a worn standpipe o-ring, or a multiport valve that is leaking water past the spider gasket. All four let unfiltered water skip the grids. The W3DE3620 is a well built filter, but every one of these parts is a wear item that eventually gives out.
How do I know if a grid is torn?
You have to open the filter and look. There is no shortcut, and a visual check takes about twenty minutes once the tank is open.
- Shut the pump off at the breaker and open the air relief valve until all pressure is gone.
- Drain the tank, unclamp the band, and lift the top half off.
- Pull the whole grid assembly out and rinse every grid with a hose.
- Look at the fabric in good light. Tears usually show up along the seams, near the bottom corners, or anywhere a grid has been rubbing against its neighbor.
- Check the top manifold for hairline cracks, especially around the ports where each grid seats.
- Inspect the standpipe o-ring. If it is flat, cracked, or missing, DE walks right past it.
Wet fabric hides small holes. Let the grids dry for a few minutes and the tear usually becomes obvious. If you find one bad grid, replace the full set. The rest are the same age and the next one is not far behind.
What else makes a DE filter blow powder back?
If the grids look fine, work through this list before buying anything:
- Multiport or backwash valve. A worn spider gasket lets water sneak between ports. You will often see this along with water trickling out the waste line.
- DE added too fast. Dumping powder into the skimmer in one shot can push it through before it has a chance to coat evenly. Mix it with water in a bucket and pour it in slowly.
- Too much DE. Overloading the filter packs the grids and forces powder through gaps. The general rule is roughly one pound of DE per five square feet of filter area, but go by the label on your filter, not a rule of thumb.
- Grid assembly not seated right. If the manifold is not fully down on the standpipe when you reassemble, you have left an open path.
- Skipping the coat after backwashing. Backwash removes the DE. If you do not recharge it, water runs through bare fabric and the fabric wears out faster.
Should you repair the W3DE3620 or replace the whole filter?
Repair it if the tank and clamp band are sound. A grid set, a manifold, or an o-ring is a fraction of what a new filter costs, and the tank itself usually outlives several rounds of internals.
Replace the filter when the tank is cracked, the clamp band is rusted through, or the filter is simply undersized for your pool. A lot of people running a small filter end up chasing high pressure and short cycles forever. Moving up to a 36 square foot unit like the W3DE3620 fixes that at the root. It also filters finer than sand or a cartridge, which is why people who want really clear water keep coming back to DE.
What to check after you put it back together
Once the W3DE3620 is buttoned up, run the pump with the air relief open until water comes out steady, then close it. Write down the clean starting pressure on the gauge. That number is your baseline, and when pressure climbs eight to ten PSI above it, it is time to backwash and recharge.
Then add your DE slowly through the skimmer and watch the returns for a few minutes. If powder still comes back after new grids, the manifold or the valve is next on the list. If the water clears up and stays clear, you are done.
Not sure this is the right part for your problem? Reach out and we will help you figure out exactly what you need before you spend money on the wrong thing.