BYPASS VALVES ON S PLAN AND Y PLAN HEATING SYSTEMS – Short Cycling prevention – Plumbing Tips

Posted on: February 16, 2017 by in Plumbing Videos
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BYPASS VALVES ON S PLAN AND Y PLAN HEATING SYSTEMS – Short Cycling prevention – Plumbing Tips

This video is all about the bypass valve on your heating system. They can be found on S plan, Y plan and C plan heating systems but also on Combi systems. They are very important when it comes to having a happy heating system, with proper flow around all the radiators and hot water coil without too much stress on the pump.

We cover where they are in relation to the system, how they work and how to set one up. For any more help, please comment below and we’ll try to help you out!




If you’ve come across this video trying to find out a bit more information about the bypass valves in your heating system, then great, we’re gonna cover them in seconds from now. Before we do, I’d please like to ask you to subscribe. We do loads of videos every week, and all that. We do lots of photos and videos and stuff on our Facebook channel as well. There’ll be a link to that coming up in the video. Anyway, I hope you enjoy the video today, and remember everyone, to hold tight. Honest reviews and advice. Hold tight and welcome to today’s video.
My name’s James and this is gonna be a really, really quick video. What we’re gonna talk about today is bypass valves. Now on this particular system here, we’ve got a bypass valve that’s effectively a gate valve. So that means that you set it at one point, and then leave it for the rest of it’s life. But you can also get automatic bypass valves that are a lot better because they’re a lot more efficient for the heating system, but for the purposes of this video, to see where they fit in on a heating system, this particular layout that we’ve got behind us here is just fine. So if you come over here and have a closer look, I’ll give you an idea about what bypass valves do, where they sit in the heating system, and then we’ll go back to the white board to show you this lot all laid out schematically. So all right, on this system here, we’ve got our flow coming up from the boiler here. It goes through the pump, and the up. We’ve got an automatic air vent up there so that just vents the pump out. And it comes back down here, and this is a S-plan system. At this point here, it’s really important. Effectively it can go one of three ways. If the radiators are calling for heat so the programme is calling for, and also the thermostat’s calling. This two port valve here is going to open up, send a live supply to the boiler, and the pump to come on. That’s great, brilliant, everything’s good. We’ve got loads of water coming around there. If this tank here is calling for heat, so the programme is calling for heat, and the thermostat in the centre of the tank is calling for heat, this two port valve here’s going to open up and send water around the coil of this tank here. Well funnily enough actually, this tank doesn’t actually have a call on it. It’s tank in tank beast, but let’s say this tank is not calling for heat, but this radiator valve here, the two port valve for the radiators is open. That’s where the bypass valve comes in.
So say you’ve got say ten radiators on the heating system, and they’ve all got thermostatic radiator valves on them. As those thermostatic radiator valves turn down and turn down, on an old system, and also on some of the new systems as well, that’s gonna cause more stress on the pump. Now that’s where the bypass valve comes in. The bypass valve, especially in the type that we’ve got here, is set to constantly let a small trickle of water through directly onto the turn back to the boiler. What that means is is that you’ve got a constant flow around the heating system at all times regardless of whether the radiators are open or either of the two port valves are open. This is also really handy if either of these valves fail. So to recap really quickly, the bypass valves ensures that there’s a constant flow of hot water around the heating system through the boiler and the pump at all times regardless of whether there’s been a problem with any of the valves or if the TRVs are open or closed. So why do we want to do that? That’s the big question.
If either of these valves go wrong or there’s some sort of problem and flow is completely restricted round the heating system, number one, the pump is gonna struggle, okay? Now in new modern pumps like this Waller that we’ve got behind us, they actually know what pressures coming off ’em and they can actually turn themselves down automatically which saves you energy. But even with that function there it’s never going to fully switch itself off. And likewise with an older pump as well that doesn’t have this automatic function on it,
they’re just gonna keep bashing away at the certain speed that they were running at.

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