Omega Double Union Spring Check Valves – Clear & Solid Body

Omega Double Union Spring Check Valves for Imperial PVC Pipe

These Omega check valves provide automatic backflow control in compatible pond pipework. A spring-loaded mechanism opens under forward flow and closes when that flow falls away, helping to prevent water travelling back through the line. The double union arrangement allows the central section to be removed for inspection after the system has been safely isolated and drained. Choose the required body style and imperial connection size from the options.

The range includes solid-body valves in 1½ and 2 inch sizes, and clear-body valves in ¾, 1, 1½ and 2 inch sizes. All the options listed here have plain solvent-weld connections and EPDM seals. They are not threaded BSP valves, flexible-hose connectors or metric socket versions. Check the existing pipe system carefully before ordering a replacement.

Available Options

The clear body offers a viewing section, which can help you notice trapped debris or an obvious change in the internal condition. It does not measure flow rate or prove that the valve is sealing perfectly. Select a clear version for visibility, not as a substitute for a proper flow meter or a controlled backflow test.

Where a Check Valve Can Help

Backflow can be an issue when a pump stops and water in a raised section of plumbing wants to return through the system. Whether a check valve is appropriate depends on the complete layout, including the pump position, water levels and the equipment connected to the line. Follow the pump and filter instructions rather than adding a valve simply because another pond installation has one.

A spring check valve introduces resistance. The pump must have enough available pressure to open it and deliver the required working flow through the rest of the system. Nominal pipe size does not tell you the pressure loss at your intended flow rate. For very low-head or gravity-fed arrangements, check suitability carefully before fitting a spring-loaded valve.

Match the Pipe, Not Just the Number

Imperial pressure-pipe sizes are nominal designations. A socket labelled 1½ inch is not a 40mm waste-pipe socket, and a 2 inch pressure fitting is not automatically compatible with 50mm waste pipe. Measure the existing pipe and check its markings and fitting standard. If a transition is needed, use a correctly specified adaptor rather than trying to fill a loose fit with extra cement.

For a new run, see our imperial pressure pipe and choose matching connections throughout. Where equipment uses a threaded port, an appropriate plain socket to male BSP adaptor may be needed. The check valve itself is supplied with plain sockets, so a thread adaptor is an additional component, not something included in the selected option.

Flow Direction and Installation Position

Identify the intended direction of water flow and follow the arrow or directional marking on the supplied valve. Reversing a check valve can stop circulation rather than protect the system. Check the manufacturer’s permitted installation orientation for the exact valve before fixing the surrounding pipework. Do not assume that an instruction for a hinged flap valve also applies to a spring-loaded model.

Position the valve where its unions remain accessible. Allow space to withdraw the central body and support the pipe so the valve is not carrying the load of a pump or a long pipe span. Think about where water will go when the section is drained for cleaning. Accessibility is particularly useful in pond systems where small pieces of debris may eventually reach a valve seat.

Keep Automatic Backflow Control Separate from Isolation

A check valve is not a lockable maintenance shut-off and should not be the only protection against water reaching an opened pipe. Before undoing either union, switch off the pump, isolate the section independently, release pressure and drain it. Suitable manual double union ball valves or another properly designed isolation arrangement serve a different purpose.

For comparison with another named range, see our Aqua Source non-return spring check valves. Compare the actual connection dimensions and operating requirements; an equal nominal diameter does not establish that different brands’ bodies, collars or seals are interchangeable. Replace the complete compatible assembly unless a specific spare is confirmed for the model.

Solvent Welding and Commissioning

Use a cement suitable for the specified pipe and socket material. Prepare the joint as instructed by the pipework and adhesive manufacturers, keeping solvent and cement away from the internal mechanism and EPDM seals. A union seal is not a surface to glue. Assemble the pipework without forcing it out of alignment, and allow the full required cure before filling or running the pump.

Once the installation is ready, fill and test it in a controlled way. Confirm forward circulation, inspect for leaks and check the behaviour when the pump stops. Do not leave a new installation unattended on the assumption that a newly fitted check valve guarantees zero leakage in every condition. Debris on a seat or an incorrectly fitted component can still prevent proper closure.

Routine Checks and Supplied Contents

Inspect the valve during routine filter maintenance and investigate reduced circulation, unusual noise or unexpected reverse flow. Clean only after isolation and follow the instructions for the supplied model. Avoid improvised chemicals or tools that could damage the seat or seals. This purchase supplies one selected Omega valve; pipe, cement, adaptors, support clips and separate manual isolation valves are additional items.