
Maytronics Grey Diagnostic Non Return Flap, 9985280
30 day returns · Easy, with prepaid labels provided
Quick overview
- Genuine Maytronics Factory part number 9985280, the flap Dolphin cleaners are built with.
- For Dolphin robotic cleaners Listed by Maytronics for use with its Dolphin robotic pool cleaner range.
- One way only A non return flap lets water and debris pass in and stops them washing back out.
- Grey version This is the grey flap, so match the color to the one you are taking out.
- Small part, real effect A flap that has curled or torn lets the cleaner drop what it just picked up.
- Quick to change It is a service item, replaced without opening the drive side of the cleaner.
Need a hand?
Frequently bought together

Grey Diagnostic Non Return Flap, 9985280
Similar products
Other products people compare with this one.
Maytronics Non Return Flap, 9980891$999
Maytronics S Series Non Return Flap, 6350150$1299
Maytronics Dolphin Grey Front Wheel, 9983410$1399
Maytronics Grey Active Brush, 9983122-R1$1299
Maytronics Grey Rear Wheel, 9983112$1099
Maytronics Wheel Bushing for Dolphin Pool Cleaners, 9983114$799
Maytronics Float for Side Panel E55/Liberty 6250951$799
Maytronics Dolphin Impeller with Screw, Black, 9995266$1599
Maytronics Dolphin Blue Front Wheel, 99834107$1399
Maytronics Rubber Strips for Dolphin Pool Cleaners, Kit of 10, 9991732$1199
Maytronics Active Brush Gear S, 9983123$1399
Maytronics Cartridge Filter Frame Holder, 9980733$1199
Maytronics Dolphin Chassis Inlet Strip, 9983262$1499
Maytronics Diaphragm 2010, Pair, 9991046-ASSY$799
Maytronics Dolphin Robotic Pool Cleaner Wheel Bearing, 3884073-ASSY$1599
Maytronics Dolphin Hexagon Drive Shaft, 3865005$1699
Maytronics Dolphin Impeller and Screw, 9995269$1599
Maytronics Dolphin S-Series Rear Brush, 6101311-R1$1299
Maytronics Filter Bag Clip (2 Pack), 9981430-R2$1499
Maytronics Dolphin Botia Black Impeller Cover 99806252$1399
Product details
Maytronics 9985280 is the grey diagnostic non return flap for Dolphin robotic pool cleaners. It is the genuine Maytronics part.
What it does
A non return flap works in one direction. As the cleaner draws water in, the flap opens and lets water and debris through. When flow drops or reverses, the flap closes and holds what has been collected inside the machine. It is the reason a Dolphin can be lifted out of the pool without dumping its load back into the water.
When to change it
Flaps stiffen, curl and tear with age and chemical exposure. A flap that no longer lies flat cannot seal, and the symptom an owner sees is a cleaner that runs its full cycle but leaves debris behind or trails dirt as it comes out. It is a small, inexpensive part to keep on hand.
| Brand | Maytronics |
|---|---|
| Manufacturer part number | 9985280 |
| Type | Diagnostic non return flap |
| Color | Grey |
| Fits | Maytronics Dolphin robotic pool cleaners |
| Shipping weight | 0.1 lb |
| Ships | Parcel |
Request a quote
Need a volume price, a freight quote, or pricing in writing before you order? We reply the same business day.
From Maytronics

Residential cleaners
Maytronics Dolphin Explorer E20 Robotic Pool Cleaner, 99996148-XPB
Maytronics Dolphin Explorer E40 Robotic Pool Cleaner, Wi-Fi Enabled with Wall Climbing and Waterline Scrubbing for Inground Pools up to 50 Ft
Maytronics Dolphin Nautilus CC Plus Robotic Pool Cleaner with WiFi, 99996409-PCI
Maytronics Dolphin Nautilus CC Supreme Robotic Pool Cleaner with WiFi, 99991083-PC
Spare parts
Maytronics Genuine Dolphin Replacement Power Supply for Wi-Fi Models, 99956083-ASV10
Maytronics Dolphin Ultra Fine Filter Cartridges, Set of 4, 9991432-R4
Maytronics M5, C3, C4 and Wave 90 Active Brush Assembly, 9995541-R1
Maytronics Dolphin Universal Pool Cleaner Caddy, 9996084-ASSY



Customer reviews
More from Maytronics
Maytronics Black Motor Unit for Dolphin Nautilus CC Plus and M200, 99953051-EX$28900
Maytronics 99953054-EX Motor Unit for Dolphin M400 and M500 Pool Cleaners$37999
Maytronics 50 Ft Blue 2-Wire Cable, 9995884-DIYF$9999
Maytronics Genuine Dolphin Replacement Power Supply for Wi-Fi Models, 99956083-ASV10$29199
Maytronics Dolphin Advanced Power Supply, 99956035US-F1$29999
Maytronics Dolphin Active Brush Gear Z12, 9983018$699
Maytronics Gear for Drive Motor Unit S50, 9983142$599
Maytronics Dolphin Explorer E40 Robotic Pool Cleaner, Wi-Fi Enabled with Wall Climbing and Waterline Scrubbing for Inground Pools up to 50 Ft$1,44900
Web Price
Maytronics Gray Tracks (Set of 2), 9983152-R2$3499
Maytronics Motor Unit for Dolphin S200, S300 and S300i, 99953058-EX$35399
Maytronics Dolphin 2-Wire Cable with Swivel, 60 Foot, 99958907-DIY$14999
Web Price
Maytronics Dolphin Cable 2-Wire 60-Foot with Swivel DIY, 9995862-DIY$17999
Web Price
Maytronics Dolphin Diagnostic Foam Wheel Ring 4 Pack, 6101611-R4$2999
Maytronics Dolphin (2026 Model) Explorer E25 Wi-Fi Robotic Pool Vacuum Cleaner Pools up to 50 FT - Waterline Scrubber Brush, 99996406-XPI$88900
Maytronics 60' 3-Wire Swivel Cable, 9995899-DIY$25399
Maytronics Dolphin Rear Brush Assembly, Dynamic Grey, 9995548-ASSY$4699
Maytronics Activate 25 lbs Glass Filter Media, Fine, A999008$19699
Maytronics Dolphin Track, Gray (Pack of 2), 9985006-R2$3499
Maytronics Cable with Swivel 60-Foot DC, 9995872-DIY$25499
Maytronics Dolphin Nautilus CC Plus Tune-up Kit$16299
Questions and answers
What people ask about this product, answered by our pool techs.
What does a non return flap do?
Which cleaners does it fit?
Does the color matter?
Why would I replace it?
Get your unadvertised price ›






