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3/4-inch threaded plug (20 x 27), white
Regular price
$4.00
Regular price
Sale price
$4.00
Unit price
/
per
$1.33 × 3 with no fees
Klarna.
This 3/4 inch female threaded cap, or 20 x 27 in French designation, screws onto a male thread to close off a water outlet. It is the original part that seals the threaded outlets of the GrowStream system's growing chambers, with a flat gasket.
It is moulded in white polypropylene and sold singly or in packs of 2.
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The summary
- What you receive: 1 or 2 white threaded caps, depending on the format chosen.
- The thread: female, 3/4 inch pitch, i.e. 20 x 27.
- The seal: a flat 3/4 inch washer at the bottom of the cap, or PTFE tape on the thread.
- The use: GrowStream channel outlet, unused outlet, leak test.
Screw-on polypropylene cap to close a 3/4 inch threaded outlet, 20 x 27
A threaded outlet that is no longer used, the end of a gutter or a fitting waiting to be connected can be closed off neatly with a screw cap rather than with adhesive tape. This threaded cap screws onto a 3/4 inch male thread, designated 20 x 27 in French plumbing, the one found on GrowStream gutter outlets. It measures 38 mm in diameter by 22 mm high, and you tighten it by hand, with no spanner needed.
🔩 Reading the 20 x 27 designation
In French plumbing, a thread is designated by two numbers inherited from steel pipes, the inside diameter and the outside diameter of the pipe, and not by the measurement of the thread itself. So 20 x 27 corresponds to the 3/4 inch gas thread, 26 x 34 to the 1 inch and 15 x 21 to the 1/2 inch. To check an outlet, measure the outside diameter of its male thread with a calliper, and a value close to 26 mm confirms 20 x 27.
End of the gutter
It seals a threaded outlet on a GrowStream growing chamber that you are not connecting.
Unused outlet
It plugs a 3/4 inch outlet left unused on a manifold or a valve.
Pressure test
It temporarily closes off a circuit while you look for a leak.
Closing the channels of a GrowStream system
The hydroponic gutter system uses this cap to close the end of its growing channels and keep the solution inside. By replacing it with the original model, you restore the intended watertightness, without resorting to a sealant that would get in the way of dismantling for cleaning the gutters.
Always add a flat seal
The thread alone is not enough to make the cap watertight. Place a 3/4 flat EPDM washer at the bottom of the cap, 5 mm thick like the original on a GrowStream channel, or wrap three turns of PTFE tape around the male thread. Tighten by hand, without tools, as overtightening will crack the polypropylene.
Polypropylene is a common food-grade plastic, neutral for water and for the nutrient solution, and it does not corrode like a brass plug. Its white colour matches that of white gutters and reservoirs, keeping the installation uniform. You can unscrew and refit it at every clean without wearing the thread, provided you replace the flat gasket when it flattens.
Take a system of 20 plants with 4 gutters, which you take apart at the end of the season to clean them. It has 12 caps, 3 per gutter, and the pack of 2 is mainly useful for replacing parts damaged during dismantling in one go. Keep a spare cap, because a part cracked by frost or overtightening puts a whole gutter out of action until it is replaced.
🧼 Taking it apart for cleaning
Before unscrewing, empty the gutter, otherwise the remaining solution will pour out all at once when the cap is removed. Once it is off, rinse the cap in hot water with a small brush, and clean the gutter with a rinsing product suited to the circuit. Check the flat seal each time you take it apart and replace it if it is crushed or split.
🧰 Individually or in packs of 2
The single cap replaces a lost or cracked part, while the pack of 2 replaces two parts at once or leaves you with a spare. To connect a flexible pipe to a threaded outlet rather than seal it, choose a barbed fitting of the same thread pitch, and the maintenance guide for a soilless system lists the watertightness checks to carry out each month, seals and caps included.
Technical specifications
The stopper
- Thread
- Female, 3/4 inchThat is 20 x 27 in French designation
- Footprint
- Ø 38 x 22 mm
- Material
- Polypropylene, white
- Manufacturing
- Netherlands
Use and format
- Watertightness
- Flat gasket, 3/4, 5 mm thickOr PTFE tape on the thread
- Tightening
- By hand
- Formats
- 1 or 2 caps
- Original system
- GrowStream gutters6 plugs on the 10-plant model, 12 on the 20-plant
To budget for separately
- Seal
- 3/4 EPDM flat gasketOne seal per plug, to be replaced when it flattens
- System
- The drip system
2 further specifications are available in the detailed view.
In the box
- 1 or 2 3/4-inch threaded plugs, depending on the size chosen
Thread, dimensions, material, origin and quantities per system taken from the GrowStream V2 assembly instructions, the parts catalogue and the manufacturer's shop, on 08/10/2026.
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Stopper sent by tracked parcel from France. The exact costs and final delivery times are shown in your basket once you have entered your address. Outside the European Union, import duties and taxes remain payable by the recipient.
Frequently asked questions
6 questions
6 key questions
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