Flojet 20381-003 Quad Port Kit, 5/8" Hose Barb
The Flojet 20381-003 is the genuine Quad-Port snap-in fitting with a 5/8" hose barb and an EPDM O-ring. Five-eighths is the intermediate size between the common 1/2" and the larger 3/4".
Intermediate sizes exist for a practical reason: matching what is already there. A great deal of marine plumbing was installed years ago in whatever size suited at the time, and cutting back a sound run of 5/8" hose to fit a 1/2" port means either a reducer at the pump or replacing the hose. Having the port available in the hose size you actually have removes that choice entirely — the pump connects directly to the existing plumbing.
There is a performance argument too, particularly on the inlet. A larger bore means lower velocity and less friction loss in the suction line, which helps priming and reduces the chance of cavitation. If your system is plumbed in 5/8" hose, using a 5/8" port preserves that advantage instead of throttling it at the pump. Push the fitting fully home, check the O-ring is seated and undamaged, and fit the clip before pressurising.
Key Features
- Genuine Flojet (Xylem) service part — correct port and barb specification
- Quad-Port snap-in fitting — no threads, no sealant, no torque to judge
- 5/8" hose barb to match existing intermediate-size plumbing
- EPDM O-ring suited to water, drinking water and mild chemistries
- Full bore at the port keeps suction-side friction loss low
Applications
- Flojet pumps with Quad-Port snap-in port housings
- Systems already plumbed in 5/8" hose
- Avoiding a reducer at the pump on the suction side
- Replacing a port with a damaged O-ring groove or broken clip
- Marine, RV and mobile potable water systems
Specifications
- Brand: Flojet (Xylem)
- Manufacturer Part Number: 20381-003
- Part Type: Quad-Port snap-in port fitting
- Connection: 5/8" hose barb
- O-Ring Material: EPDM
- Condition: New
Frequently Asked Questions
Q: Is it worth matching the hose size exactly?
On the suction side, yes. Reducing at the pump adds restriction exactly where the pump has the least margin, and priming performance is what suffers.
Q: Can I fit 1/2 in. hose onto a 5/8 in. barb?
It will not seal properly however hard it is clamped. Use the barb that matches your hose, or a proper reducing fitting if the sizes genuinely differ.
Q: Does a larger port increase flow?
It removes a restriction rather than adding capacity. The pump determines the flow; the plumbing determines how much of it you actually get.
Q: How do I measure hose size?
By internal diameter. Hose is specified by bore rather than outside diameter, which is why two hoses of the same nominal size can look quite different.
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct part before you order.
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