Pipe unions
in category: Pipe unions
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Unions and half unions for water meters and water installations
Unions and half unions are brass fittings for water installations. This category includes water meter half unions, adjustable versions and versions with a non-return valve, equal-bore half unions, a pump half union, and straight and angled unions with O-rings. The range is intended for installers and contractors fitting or replacing water meters, pumps and pipework sections.
What you’ll find in this category
- Brass water meter half unions in sizes 1/2" - 6/4" and lengths from L-30 to L-60.
- Adjustable 3/4" water meter half union with a length of 50-70 mm.
- Brass 1/2" L-37 and 3/4" L-37 half unions with a non-return valve.
- Equal-bore half unions in 1/2"×1/2", 3/4"×3/4", 1"×1" and 5/4"×5/4".
- Brass pump half union in 1"×6/4".
- Straight brass unions with O-rings in sizes 3/8" - 2".
- Angled brass unions with O-rings in sizes 1/2" - 5/4".
How to choose
- Fitting type: Choose a half union for a water meter and a union to connect two pipe sections. Where protection against water flowing back is needed, choose a version with a non-return valve.
- Size: Match the size to the connection, from 3/8" to 2". For equal-bore and pump half unions, check both sizes, e.g. 1"×6/4".
- Length L: For a water meter, choose the required installation length, e.g. L-30, L-37, L-45 or L-60. Where the distance between connections may vary, consider the adjustable 3/4" version with a length of 50-70 mm.
- Threads and configuration: Check the thread type (female or male) on the dimensioned drawing. On the 1/2" L-30 half union, the body has a G1/2" male thread and the nut has a G3/4" female thread. Also choose a straight or angled configuration.
- Operating parameters: The variants described are made of brass, with a maximum working pressure of 10 bar and an operating temperature of 5-95 °C.
Typical applications
Half unions are used to install water meters, while adjustable versions make it easier to accommodate the required length when replacing a meter. Versions with a non-return valve are installed where water must not flow back into the mains. The pump half union connects the unit to the pipework. Unions with O-rings connect sections of an installation in a straight or angled configuration.
Frequently asked questions
How do I choose a water meter half union?
Check the connection size and required length L, e.g. L-30, L-37 or L-46 for 3/4". Also compare the threads with the dimensioned drawing and the variants table on the product page.
What threads does the 1/2" L-30 water meter half union have?
The body has a G1/2" male thread and the nut has a G3/4" female thread. Check both threads before ordering.
What pressure and temperature are these fittings rated for?
The brass variants described have a maximum working pressure of 10 bar and an operating temperature of 5-95 °C. Check the product page for the specifications of the particular product.
Not sure about the length L or the threads? Contact technical support and we’ll help you choose the right product.