Deva NRV15 Brass Non-Return Single Check Valve 15mm Compression Fitting 1 Way Prevents Water Backflow Hot Or Cold for Showers Toilets and Outdoor Taps Anti Corrosive

Perfect for the job. Good value.

This little thing is being used befor the booster pump on the main water inlet. The reason is to dont let the water to flow back and stoping the booster pump to switching on every so often for a short term to build the pressure up in the pipes. If there is no NRV in your system then the water can flow back and because the pump pressure sensor feels the pressure drop it will switches on for a short term to get the set pressure in your pipe system, even if you never opened a tap. So this is esential for booster pumps!!!!

The valve is reasonably short, and seems to work well. However, the compression nuts are strange. They are 25mm A/F and have very rounded corners leaving little "flat" for a spanner to lock onto. I was very uneasy about using them so I used a pair of normal sized nuts from a redundant compression joint instead.

So far so good, easy to install, seems like a good solid quality, no noise, no leaks. Happy customer!

These work, but of the three I bought, two required considerably higher pressure to open than the one I ended up using, on a fairly low pressure hot water supply. Also, the nuts and the flat on the body of the unit could be easier to manipulate with a spanners, which tend to slip off rather easily. But it has done the job.

To repair a leak

Bought this for my drill pump, no back flow now sir!

As another poster said - the nuts on these are useless. The actual fitting seems ok and the valve works. I too replaced the nuts with some I had in my toolbox. I would pay another couple of quid next time and get a better one.

Poor quality and it ended up in the bun.

Bought these for toilet supply outlet to water tank. They are well made & easy to install. Something worth getting to assure no water contamination. Excellent product.