Surrey Flanges – How They Work – Plumbing Tips

Posted by in Plumber Talk, on September 14, 2017


How Surrey flanges work. How they prevent air from entering a shower pump using a dip tube in a hot water cylinder. How to install one. For more information visit

Hello and welcome to this video. Today we’re gonna look at Surrey Flanges. It’s gonna be absolutely…mediocre. But as ever, incredibly informative.
Here is the Surrey Flange. Now, Surrey Flanges are only ever used when you’re going to pump hot water using a shower pump that comes out of an indirect tank. Now the idea of a Surrey Flange is to take water from slightly further down inside the hot water tank to prevent any air getting in to the shower pump and, basically, making the shower pump fail. This bit here is the Surrey Flange. Now, usually, a unvented tank like what we’ve got here would just have the pipe going directly into the top of it using what’s called an inch BSP to 22 mm compression fitting which is actually this fitting here. That fitting is usually there and this actually Surrey Flange isn’t here. And what we do, when you’re gonna put a Surrey Flange on, this bit gets unscrewed and you pop that out, you put the Surrey Flange in and if you imagine going down the inside of here is a small tube that takes water from slightly lower down in the tank and that prevents air getting into the shower pump. Let’s quickly go to the office and I’ll do a quick diagram so you can get a bit more of a better idea of how these work.
So, normally, you just have your hot water tank and your shower pump and, usually, out the top of the tank, you just have your hot water going into the shower pump and then pumped off to you shower head. On this side you have the cold coming in. So the problem we often have is you have air bubbles in here and they can percolate up, into this pipe, down into the shower pump impeller and basically make it go wrong. The idea with the Salamander S Flange is, if we take a closer look at the top of the tank,. instead of just taking its water supply just out of the top of the tank, and allowing air to go up, a Salamander S Flange has a small dip tube that goes further down and that dip tube is what draws off to the shower pump. ‘Round the outside of that dip tube is the water supply that goes off to your normal taps. That’s how it works.
So water for the shower pump gets drawn in here, at a lower level, and water to go off to your taps and elsewhere, goes in through the outer collar and off like that and takes the air away with it. That’s how an S Flange works. So the inner pipe runs into here and goes down to our shower pump. So that’s how a Surrey Flange works. If you ever get a plumber come ’round and they want to fit you a new shower pump, always ask them whether they can fit a Surrey Flange in there as well. Because that’s always only gonna extend the life of your shower pump and pretty much cut the chances of it getting air in the impellers and blowing the pump up.
I hope you found today’s video interesting and helpful if you’re thinking about doing any of this sort of work. If you have any questions or you think we’ve missed anything out, do let us know. And as ever, favourite and subscribe to our videos. Thanks ever so much for watching and I’ll see youse all laters! Blah! honest reviews and advice.

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