Posted by in Plumber Talk, on June 25, 2017

This video will tell you how to change an immersion heater element in your hot water storage tank. It will tell you how to isolate the electrics to the immersion heater and how to drain the tank. It will tell you how to remove the old element and replace it with a new one.




Today we’re going to be having a very quick look at the murky, dark world of top-entry immersion heaters. Now, this immersion heater here isn’t working very well. Or it’s not working at all. They basically found out because their heating system went mad. They turned their immersion on as a backup and nothing happened. Next thing you know, I’m getting a phone call. Oh my God, we got no hot water. Get Jimmy from PlumberParts out here right now. So here I am. So basically the procedure that we go through when we change an immersion heater is to firstly isolate electrically the immersion heater. Make sure that’s done. If you’re not happy doing that then I suggest you don’t even carry on with this job and get a proper real plumber like me to come out and do it. The next thing we need to do is turn off the cold water supply to the bottom of the hot water tank. Then we drain down the hot water at the top. We can do that firstly by opening all the hot taps in the house. And then secondly, by finding the drain off at the bottom of the tank. Now because this is a top-entry immersion heater all we’ll need to do is drain out a couple of litres out of the whole tank itself. Also, I’d say as a small tip is to try to try and loosen off the immersion when it’s full of water, okay? ‘Cause that water tends to stabilise the copper tank because they can be prone to ripping because you’ve got a very fine, thin copper wall that’s holding the whole tank together. So do that first. Make sure then that you drain off about five to ten litres worth of water. You should know that it’s drained out okay if you crack the nut on the outlet at the top. You’ll know then that everything’s all right. So anyway, if you follow us as we go along and do it, I’m sure you’re gonna enjoy this as much as I am because this is the best job you could ever do. Especially when you’re round one of your mate’s houses. Anyway, I hope you enjoy this video and it helps you out if you’ve got a top-entry immersion heater that’s gone wrong. So nice and easy when it comes to switching this off. It’s just on this plug here. We can just unplug this plug and then we know that there’s no power going into our immersion heater. So if we take a closer look at the actual tank itself. This here is our hot outlet, okay? So this is the hot water that’s going out to our taps. Obviously we’ve got our immersion heater at the top just there. Down here we have our flow and return from the coil of the boiler. So there’s our flow there and that goes through a coil and then back out. Nice and simple. A little bypass valve down there. But then the bit that we’re worried about at the moment is the cold feed. So we have our drain off just here, like so. We follow this pipe up. We should be able to see that we’ve got a big valve. This one here. So what I’m gonna do is turn off this valve here now. You should now be able to open up all the hot supplies. What that’s doing at the moment is draining out the expansion pipe up to loft. Now as you can see that’s pretty much stopped running now. At this point if we find that this is still dripping here, you’ve probably got a problem with that valve there holding. Therefore you might have to turn the mains off, open that valve up fully again and then basically drain the whole tank out. Alternatively, if you have the facilities, you can actually bone the tank but you need special bones to do that. And if you’re here watching the video about how to do an immersion heater, you probably don’t have those tools with you. So, as you can see this is still running a little bit. We’re just going to open up a few more taps and if we’ve got a problem with that valve, we’ll address that now. Right, so now we’ve got the water off. We know that the valve’s holding. And basic now, the water level of the hot system is about up to the top of the tank there. Before you carry on, make sure that all the electric isolation that you’ve done is okay, all right? Make sure that you use a voltage tester. Make sure that you pull any fuses that could be nearby. And also make sure that you identify what trip the immersion is on and throw that trip to the off position as well. What we’re now going to do is get our hose on the drain off at the bottom of the tank and get that into a bath or outside in preparation.

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