– Holla, and welcome to today’s video. Today we’re gonna change
an immersion heater. It’s gonna be amazing. So, if you follow my
steps, you’ll be fine. And you won’t have any
trouble at all, so let’s go. Alright, so the immersion
heater we are changing today is an Economy 7 tank, which means it has two immersion heaters. The top one being the boost, and the bottom one
being the night setback. Unfortunately, today we’re going to be taking off the night setback one, which means we’re gonna have to drain this whole tank down, before
we can do any work. Firstly, turn off the water supply. Now we isolate the electrical supply. So what you do is find where the immersion heater switches
off, turn it off, take the cap off the immersion heater, and using a pair of electrical testers, make sure that the power
supply’s turned off and it is dead. Make sure one side you’re
testing is to earth, and you test every other
terminal on the immersion. And that is completely dead now. Now that we know the
immersion is turned off, we can drain it down. If you see this here,
this is the drain-off. We’re gonna put our hose on
that, take the hose outside, open up this valve, go
and have a cup of tea, while this is all draining down. Cause it’s gonna take a
good 10 or 15 minutes. Don’t be surprised if the drainoff leaks, they often do when they’re really old. So, we’ve got our towel
under there anyway. Here’s our new immersion heater. We just quickly remove the packaging. Small set of instructions,
put these to one side they’ll tell you how to connect it electrically, later on. And a small fabric seal that seals up this flat here with the flat on the tank. Often what I’ll do at this point is I’ll pop a bit of PTFE tape round the thread itself, and
also you should find jointing compound, or
even better copper slip. After I’ve put a little bit of PTFE on the thread, I’m gonna put some jointing compound on
this fabric washer here. Just get it all over
it, completely smear it. And that will help you
get a really good seal. Now pop that on the immersion
heater and push it right down. Do this carefully cause you can rip these fabric washers in half. Do the same again and get
loads of compound on here. Now, this is an extra precaution, you can do this if you like. Just get some PTFE tape and get that wrapped around on the thread itself. Now we’ve got this
prepared, all we need to do is wait for the tank to drain down and the we can set about removing
the old immersion heater. This bit will be difficult, but persevere. And if you go nice and
slowly, you’ll be great. The next small tip I have, is now you’ve got this prepared, while the tank’s still draining down, go back to the immersion heater, remove the wires, and just loosen it off while there’s still
some water in the tank. Because, the water in the tank will help to stabilise the copper
wall of the tank itself. If there’s no water in there, you could end up rippin’ the whole
flange out of the tank and getting yourself a whole new tank. And you don’t want that to happen. There’s a constant risk while trying to remove these. So if you loosen off while
there’s water in the tank, it will still be nice and stable, and with any luck, you
won’t rip the flange off. Let’s have a go at that. First you remove these wire clamps. Free up the wire, remove the neutral. Remove the live. And using your small adjustable
remove the earth wire. For this part, you are gonna
need some specialist tools made specifically for
removing immersion heaters. This is an immersion heater spanner. This is just one type,
I’ve got another type here. And if I really need it, I’ve also got a nice big pair of grips
that can grab it as well. So let’s get this old
immersion heater loosened off. And then once the hose stops, we can actually fully remove it. So, we put a towel along the bottom here, just down here to get any
water that might come out. Pop our immersion spanner on,
make sure it’s fully home. Then get my large pair of grips and turn that anti-clockwise to just loosen it off a little bit. I mean, that was tough. That pretty much took all my strength just to loosen it off. So, apply yourself
properly, prepare properly and you will be able to loosen it off. Just be really careful. If you feel that it’s starting to buckle just stop, re-jig up the whole
job and then try again okay. Just take it easy, apply
yourself and it’ll be okay. So now we’ve loosened it off, we just need to wait for
the tank to fully drain down and then we can properly rip it out rand pop the new one in and connect it up. Right I’m back, the tank
has stopped draining now so it’s indicated that it’s
completely fully drained down. So now we’re gonna fully
remove the immersion heater and get on with the job. Right, so there we are, the
old busted immersion is out. Now’s a good time to look through the hole and actually see if
there’s any scale in there. Try and get that out if you’re
doing a bottom outlet one. Otherwise if you’re at a top outlet one you’re not gonna be able to do that. So, now we can pop the new one in wire it up and get it all up and running. So here’s our new one, ready to go in, so, pop it in like this,
offer it up to the hole. And, screw it in. Just do this nice and lightly. If you feel any kind
of unknown resistance, that means you’ve
probably crossed a thread. So just work back as soon as you can wait for the thread to click, and the start screwing
it top-wise up again. Screw in there a bit further, just carry on tightening
after this, with your socket. Just tighten up, just nip
it up lightly for now. Now you’ve done that part there and you’ve tightened it up lightly, open up all the hot water taps and then turn the cold
water supply back on. Once that’s all filled up, and you’ve got water coming out of the hot water taps, you can test for leaks. If there’s no leaks,
we can then wire it up, turn it all back on, and hopefully we’ll get hot water in
about an hour or two. We turn the drainoff
off and tighten that up. But leave your hose on just in case you’ve got any troubles. Turn the cold water supply back on. And then after you have
water coming out of your taps you can then test for leaks. Now I’ve got water coming out of the taps, there’s no leaks, and so that means we can now, connect up the electrics and get everything heated up, and make sure everything’s working fine. Unscrew the small cap on the top. So using your slotted
screwdriver, I’m going to connect my live to this
side of the thermostat, my earth to the earth pole here, and my neutral to this screw just on here. And all of them are gonna get clamped into this little clamp there, so it can’t be pulled out
accidentally after I’m gone. Just like that. So, you put your live in here, the earth on that pole there, and our neutral there, and
it’s all nicely connected. So you put the cover back on. Do the little screw up. Now we’ve got the electrics back in, the cover on, there’s no leaks we can turn the electrics back on, and hopefully about an hour or two, you should notice this is getting hot. Remember if you’ve done the
Economy 7 immersion heater it won’t be getting hot until the evening, and there’s no way you
can override that clock. So there we go, we’ve
changed the immersion heater on the tank successfully. There’s no leaks, it’s getting hot and everything seems to be okay. If you think we’ve missed
anything or you think we could do anything
better do let us know. And as ever favourite and subscribe. If you need anymore information visit our website I hope you have a lovely time
and I’ll speak to you soon. Hold tight! – [Voiceover] Honest reviews and advice

70 thoughts on “HOW TO CHANGE AN IMMERSION HEATER – Plumbing Tips

  1. Well done mate, it's not an easy one replaceing the immersion heater, it can be a real James Hunt to unscrew it!! You covered most things, perhaps you could of shown testing the element with a multimeter, ohms law etc? Another tip your viewer may like is using a blowtorch if it's too tight to unscrew; remove the thermostat & heat the centre of the old immersor for a good few minutes(don't burn the cylinder insulation), then while it's still very hot unscrew with your box spanner. Dickie…;-)

  2. @Tabassam86 It's hot water mate, not potable, wouldn't fancy drinking cylinder water??!!………Yuck!!!
    But hey, whatever lights yer candle!

  3. Excellent video, however, for a novice, you actually blocked the shot of testing the circuit with a multimeter to determine that the power was off, someone may meed to see that particular shot!

  4. @Tabassam86 Sorry mate you're quite right, it is classed as potable. You know what; that's the second time I've been wrong…………in this life time!!

    It amazing to think it was 2002 I did my Water By-laws, I think I need a refresher………!!!

  5. Here's a wee leason on testing the element on an immersion heater;
    Test everything is dead before you are, just do this if you're OK with electrics.
    Right; with a multi meter test the Ohms resistance of the element only, not through the thermostat. Ohms Law; 3000watts div 230Vac = 13Amps
    230Vac div 13Amps = 17.69Ohms
    So a 3KW immersion heater element should have a 17.69Ohms Resistance.
    Got it??

  6. Thanks ever so much Heatandplumb. A nice, straight forward step by step guide that's empowered me to get the job done myself. Really appreciate it.

  7. Can you help ? I need to replace the insert in my hot water Bath tap but I am struggling to isolate the hot water. Is it the RED valve on the piping to the front of the tank ? How long will it take to clear the hot water in the pipework ? THANKS !

  8. i have replaced my immersion heater and power going to it ok but this still is not working, anything i should be looking for??

  9. Think you should fully remove the fuse when you switch it off at the junction box incase someone comes along and turns it on whilst you are working on it. apart from that it was very informative thanks


  11. what compound are you using? had to do 2 of these on a combination cylinder, and like you said, cant fully tighten it without water inside or risk tearing cylinder open. only used fibre gasket and were there ages trying to tighten up the heaters with the spanner, ended up putting a bit of 15mm pipe over the handle for extra leverage…

  12. This was really helpful. I'm about to fit an immersion heater in a big plastic tank that I've converted into a hot tub, and this told me all the things I needed to know.

  13. another good video, hanks.

    The only thing I'm a little unsure about is how tight to fit the new element. Would I fit it hand tight and after filling then tighten it fully.

  14. Do you have a video about replacing the whole of the tank? We are on economy 7 yet have a standard tank which A, we are unable to boost during the day and B, provides not enough hot water for the family. Many thanks!!

  15. I've always loosened the element while the tank still has water in it. Doesn't need to be much, just budge it that first little quarter-turn. Sounds counter-intuitive, but an empty copper cylinder is way more liable to distort (then subsequently leak) if it's empty. If it's an unfamiliar installation, it's probably a good idea to let a littlewater out of the draincock first to make sure it isn't blocked.

  16. Before unscrewing the element Give a clockwise tightening, and then it's easy to unscrew. How KWatts is this element? If you want to drain the water, opened the tap of warm! Thanks for the video.

  17. is this common in the UK to have electrical tanks ?? Is it convenient because of venting flue gases in certain applications or is it lack of gas.

  18. My mate had a faulty Immersion heater. It had stuck on and was actually boiling the water! He only realized when the house was full of moisture! We all had a great brew though.

  19. Hi,
    I have a E7 flat and when we turn on the water heater after a time, obviously its heating the water, the feed tank starts to bubble as if the water is boilers and the pipes from boiler start to bang. Once that happens we turn the boost off and all is fine. Would that be a faulty stat i.e. never turning off or?

    Thanks in advance!

  20. just happened to me, water does drain but very slowly, I trusted in the 15 minutes as he said:) I rushed a little without thinking that by this flow there is no way it could drain 150 liters:) since I am changing the top one I thought lets see lol, and all floor in water:) I managed to close the immersion heater back but Im stuck how to drain it now lol, I guess maybe unvented tanks are a bit different than what he does here, even though great video but floor in water, hmmm what is the next step

  21. Is draining the tank the same as stopping the supply but running the hotwater at the bath tap ? I have only one immersion fitted from the top , I assume I just need to drain the water about a third .

  22. when the drain valve doesn't drain, I turn off the supply to the cylinder, open the hot taps so the hot water is drained off to the top of the cylinder. Then loosen the nut at the top of the cylinder that joins the 22mm copper pipe to the cylinder(a small amount of water will run out). Then I pull the pipe out the way and syphon the water out of the cylinder with a hose pipe, the wc or bath is normally pretty close so I just shove the other end of the hose pipe down there.

  23. my Immersion Heater Cylinder use to go bang about every 18 months for some reason my Immersion Heater Cylinder as lasted 7 years,

  24. I have one immersion heater at the top of my hot tank, can you wire it directly to a Fused switch or do you need to connect it via fuse/MCB

  25. Total overkill never use jointing compounds or ptfe tape as this is not necessary the fibre washer is all you need to to the job

  26. John, ptfe is good idea..not for seal as your right the washer does seal…but the tape stops water scaling up the threads, making it easy to remove in future…oh and crack that joint whilst full…stops tank twisting

  27. Hey John, quick Q: My bottom immersion heater doesn't seem to work but the top one does. It may be a wiring issue (new place I've moved in to). Is there any harm in me swapping the wiring around from the top one to the bottom one? I plan on installing a digital timer so having a full tank of hot is what I aim for. great post and channel BTW.

  28. Hiya John…

    I'm going to replace the immersion heater element in my hot water tank – the current model is a 11" Backer BS311C (I'm assuming the C stands for copper). I was wondering if a new Backer replacement will be wired slightly differently due to changes in regulations or even easier if I would be okay just picking up a new element from my local Screwfix just down the road (not sure of the quality of their generic elements)?


  29. like everything you do here ! 1 thing i usually do before i drain down the domestic hot water is to get the immersion spanner on the immersion and give it the first " crack " while you've got the head pressure still acting on the cylinder ! – A fully drained cylinder is a lot less stable and thus more prone to cracking with the force of an immersion spanner !

  30. Watching you undo that element worried me as you were applying all the pressure on one side and buckling the cylinder. I always put a long bar through the box spanner and apply an even pressure to both sides. I think this stresses the cylinder less. Never damaged a cylinder yet.

  31. I've just changed my thermostat as the water in my immersion tank started to bubble and boil one night but now I only seem to be getting 3/4's of the hot water I used to before it turns cold. I never changed anything just dropped in the new thermostat rod. Do you have any ideas why this could be, thanks.

  32. watching this from the U.S. its amazing to see how the procedure is the same but all the equipment is totally different. our tanks look nothing like yours, the thermostats are usually located away from the elements, and we generally don't run an economy style cutoff for a dual element. so its nice to see how things look/work on the other side of the pond 🙂

  33. we just bought a new immersion but it says it needs to be wired to mains not like the old one which was on a plug , are they all like that?

  34. My element would not move and the tank started to buckle so stopped and went and had a word with my supplier. His suggestion was to use a hot air gun to soften the jointing compound that had been use worked a treat, I did have to remove some of the insulation first to stop it burning.

  35. what kind of price would u say this would cost my old tank is just about done last guy fitted this and left it leaking it is now tripping the fuse has lasted a few years tried new thermostat just tripped again so it must be the element yes preferable woud be great to fit a new modern tank but not sure where to start

  36. Hiya, good educational video as always. My immersion heater is situated below & took at least 2 hours to drain why?. You said it will take 15 to 20 minutes. Please inform me what I did wrong. Cheers mate. Keep well!!

  37. I've just done one of these this weekend just gone and it was a right bitch of a job! Right from the start continuous issue after issue. Got it done and working perfectly in the end but I certainly don't wanna have to do that again in a hurry I can tell you.😂 but really great video though.👌👍

  38. Links to the tools I use everyday here:

    Plus, follow my Vlog “TimesWithJames”:

  39. Hi great easy to follow channel

    I have just moved home to a house that has solar panels max output just over 3kw on a hot day
    I’ve wired a timer switch on the standard 3kw immersion heater but thinking of changing it to a low power 1kw so can tap into the free power other than just mid summer .
    Question is , with the cylinder thats 22years old . would it be worth the risk of possibility damaging it trying to replace the immersion heater on a cylinder that old .

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