markharro Posted January 26, 2022 Share Posted January 26, 2022 We have an all electric house with an old copper water tank with immersion. It has recently sprung some sort of leak although hard to see where through all the old foam insulation. Anyway this got me thinking about whether to simply disconnect it and instal an instant shower. I should explain that we have been used to boiling water on the cooker to do the dishes etc rather than using the immersion as a matter of course and we hopefully only have another 6 months or so in this house before its demolished and we rebuild so fine to put up with minor hardships. So the question is could I instal something like this myself. I could easily connect the cold water feed but what I dont understand is how to shut down the tank and isolate it so that we solve the leaking issue. This and whether that will create any issues I am unaware of. There is also the issue of the electric. The immersion appears to run from an RCD on the consumer unit so I figured that is we decommission the tank I could redirect the cable that currently goes to the immersion - via the 2 pole isolator switch - to the shower. It would probably be a 8.5kw shower and from youtubing I saw a reference to needing a minimum 80A fuse in the consumer unit I think. From what I can make out our one appears to have a 60A. Would that be a deal breaker? Link to comment Share on other sites More sharing options...
markc Posted January 26, 2022 Share Posted January 26, 2022 Turning off the supply to the tank and letting it empty will stop the leak. immersion cable will not be big enough for an electric shower so a new cable would be required. 60amp incomer fuse is fine Link to comment Share on other sites More sharing options...
markharro Posted January 27, 2022 Author Share Posted January 27, 2022 Thanks for the reply. I wondered about the cable and can easily replace it with a heavier duty. A basic question but where does the cold water supply normally enter the tank - at the top? Link to comment Share on other sites More sharing options...
joth Posted January 27, 2022 Share Posted January 27, 2022 (edited) 1 hour ago, markharro said: Thanks for the reply. I wondered about the cable and can easily replace it with a heavier duty. A basic question but where does the cold water supply normally enter the tank - at the top? (To confirm, by "tank" you mean the vented hot water cylinder?) The cold water comes in at the bottom, and hot water leaves via the very top, to promote stratification. For the shower install, you can do it all except hook the new run into the consumer unit. If it's a demolish job in 6 months, maybe you can run the new T&E cable clipped in place but so it's visible, and the sparky that comes to hook into the CU can inspect the whole run and sign off the whole install. Worse case they'll charge you for re-terminating it to the shower. (And putting right any other critical issues they discover ). Ask them first though, it maybe easier just to have them do the whole lot. An 8kW shower on a 60A main fuse is fine, modulo what else you run at the same time? If you have a gas cooker and not many other high power electrical devices (kettle? microwave? hairdryer? plugin electric heaters?) then I can't see an issue. 60A is 14kW Edited January 27, 2022 by joth Link to comment Share on other sites More sharing options...
ProDave Posted January 27, 2022 Share Posted January 27, 2022 To be honest, if it's due for demolition, I would just do it, nobody is going to check or care. Alternatively, what do you plan to have in your new build? If you are going to have an unvented hot water cylinder, buy that now, and put it into the old house (you could even feed it from the header tank as a vented cylinder for now) . Link to comment Share on other sites More sharing options...
SuperPav Posted January 27, 2022 Share Posted January 27, 2022 Personally I'd probably just wire it up (assuming RCD etc. protections in place) until the place gets demolished, but if your electrician will connect it (after you've routed the cables) for £50, then i'd pay that as an insignificant enough amount. However, we have also previously survived a couple of months using a builders bucket with a battery powered camping shower hooked up to hot water in a sink (or other bucket), with a hoola-hoop suspended from the ceiling to hold a shower curtain when re-doing our bathroom if you want something a bit more creative! Link to comment Share on other sites More sharing options...
markharro Posted January 27, 2022 Author Share Posted January 27, 2022 5 hours ago, ProDave said: To be honest, if it's due for demolition, I would just do it, nobody is going to check or care. Alternatively, what do you plan to have in your new build? If you are going to have an unvented hot water cylinder, buy that now, and put it into the old house (you could even feed it from the header tank as a vented cylinder for now) . On that I dont have the technical knowledge to comment. We are building a passive house which may or may not have an ASHP. At the moment the issue is space more than anything else. Its not really an option to put in a new tank and there would then be a need to take it out and store during the build. Pretty happy I can connect up the cold water feed and from what others have said it cant be rocket science to turn off the cold feed to the water tank. The electrics are the issue. I need to be happy I can isolate the consumer unit without killing myself (having watched a few Youtubes now I think I can. But I am still unclear whether I can simply unwire the feed to the immersion and then use the empty terminals to wire in a new cable of sufficient rating (what would that be?) that goes to the pull cord isolator and then on to the shower? Or is the compromise to do all of it apart from the connection to the consumer unit and then pay an electrician to that bit? Link to comment Share on other sites More sharing options...
TonyT Posted January 27, 2022 Share Posted January 27, 2022 The immersion terminals, cabling etc are all under rated for an electric shower. a new MCB/RCBO is required from the fuse board/consumer unit generally via a double pole 45/50amp switch/pull cord. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 27, 2022 Share Posted January 27, 2022 2 hours ago, markharro said: Pretty happy I can connect up the cold water feed I assume you know that the cold feed to the copper tank is gravity, and that the cold feed you need for a regular electric shower is the cold mains in the attic that fills the CWS tank? Do yourself a huge favour and leave the electrical connections well alone Run a 6mm2 from the CU to a suitable location for a surface mounted 45a DP switch, outside the bathroom ( uglier but much easier than fitting a pullcord ) and another bit of 6mm2 from that switch location to the shower area. Leave a bit of slack at the switch on both, a bit of length to connect into the shower, and a meter or so of slack at the CU. Then fit the shower and plumb it to the cold supply. Then ring an electrician to do the rest ( please ). Not worth dying before you move into the new house eh? Link to comment Share on other sites More sharing options...
SteamyTea Posted January 28, 2022 Share Posted January 28, 2022 I would have though that changing the cylinder would be the cheapest, easiest and quickest thing to do. Or have I missed something. Link to comment Share on other sites More sharing options...
joth Posted January 28, 2022 Share Posted January 28, 2022 3 hours ago, SteamyTea said: I would have though that changing the cylinder would be the cheapest, easiest and quickest thing to do. Or have I missed something. Good point £200 for a new cylinder, and no part P electrical work needed, or you can even grab an eBay bargain if it's just for a few months https://www.ebay.co.uk/itm/325014289052 Link to comment Share on other sites More sharing options...
markharro Posted January 29, 2022 Author Share Posted January 29, 2022 On 27/01/2022 at 20:42, TonyT said: The immersion terminals, cabling etc are all under rated for an electric shower. a new MCB/RCBO is required from the fuse board/consumer unit generally via a double pole 45/50amp switch/pull cord. Great sound advice and enforcing my own tuition that the time spent in trying to learn enough to avoid killing myself is probably far too high when compared to the cost of using a pro to do this stuff. I am now focused on two solutions - trying to stop the leak which seems to be from a water inlet? (photos to follow) and continue using the current system or alternatively getting an electrician to hook up with the needed new MCB etc. On the first option, I have tried tightening with a spanner but the nut is corroded in and more force will probably do more damage than good. If there any type of sealant or glue I could use around the thread that would withstand the water pressure? On option two...I will upload photos of the consumer unit..It looks to me that there is room for the required new MCB at the left hand end but would be pleased for an opinion on that. Thanks again. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 29, 2022 Share Posted January 29, 2022 Looks like you are an Economy7 user. Fix the drips. There used to be a thick, clear silicone in a yellow tube, LSX or something it was called. Used some on a leaky joint and it worked ok. Link to comment Share on other sites More sharing options...
markharro Posted January 29, 2022 Author Share Posted January 29, 2022 Thanks for that - I see there still is...Screwfix have it and highly reviewed, this looks like the solution. Thanks again for all help Link to comment Share on other sites More sharing options...
SteamyTea Posted January 29, 2022 Share Posted January 29, 2022 1 minute ago, markharro said: Screwfix If this site was not so set against commercialism, I think Screwfix would be a good sponsor. Link to comment Share on other sites More sharing options...
markharro Posted January 30, 2022 Author Share Posted January 30, 2022 Sorry thought I was finished but one more thing - The LSX stuff says to drain the tank before applying. So next question - how to cut off the cold feed to the tank. I Have attached a photo circling what I think is the valve I need to shut off but confirmation would be welcome? thanks Link to comment Share on other sites More sharing options...
ProDave Posted January 30, 2022 Share Posted January 30, 2022 no, I think that is a drain valve (that makes your job easier) The thicker 22mm copper pipe going up is the feed. that will be coming down from the header tank in the loft. If there is no valve on that, then worst case is you have to turn off the feed to the header tank and run down the header tank before the hot tank will empty. If that is a drain valve, one of the white pipes will feed outside somewhere. Link to comment Share on other sites More sharing options...
markharro Posted January 30, 2022 Author Share Posted January 30, 2022 Thanks Dave and excuse my ignorance again but if you are right and this is a drain valve do I just need to open that and then the hot water tank will empty without opening any sink taps etc? Link to comment Share on other sites More sharing options...
ProDave Posted January 30, 2022 Share Posted January 30, 2022 You cannot empty the HW tank just by opening taps. That is why you have a dran valve at the bottom, that often you have to attach a hose to and lead the house outside to drain it. Having a fixed drain off pipe makes that easier. Link to comment Share on other sites More sharing options...
markharro Posted January 30, 2022 Author Share Posted January 30, 2022 Ah ok got you on that. I opened the valve and there is water moving but I suspect that I need also turn off the valve from the main tank in the attic or all that will happen is that it will keep refilling the hot tank!? Link to comment Share on other sites More sharing options...
ProDave Posted January 30, 2022 Share Posted January 30, 2022 Yes stop the water going into the tank, if you can't find a shut off valve then worst case is a piece of wood across the header tank and tie up the ballcock to that piece of wood. Run the hot and cold taps until they stop (loft tank empty) then open the drain valve to empty the hot water tank. Link to comment Share on other sites More sharing options...
markharro Posted February 1, 2022 Author Share Posted February 1, 2022 Hello again...right i drained both tanks and siliconed the leak and then have refilled the attic tank. The cold taps in the bathroom now flow but nothing but minor dribbles from the hot tap. So next question - does this mean the hot tank is not yet filled? If so, how do I ensure it fills? Or is it maybe because I haven't turned the immersion on yet? I expect it is yet another basic numpty thing I am missing but it is kind of annoying as I really need a shower! Link to comment Share on other sites More sharing options...
markc Posted February 1, 2022 Share Posted February 1, 2022 1 minute ago, markharro said: Hello again...right i drained both tanks and siliconed the leak and then have refilled the attic tank. The cold taps in the bathroom now flow but nothing but minor dribbles from the hot tap. So next question - does this mean the hot tank is not yet filled? If so, how do I ensure it fills? Or is it maybe because I haven't turned the immersion on yet? I expect it is yet another basic numpty thing I am missing but it is kind of annoying as I really need a shower! Either a valve turned off that supplies the hot water tank or possibly (but unlikely) a blocked vent pipe preventing air escaping so no water going in, leave a hot tap turned on for a while and listen to the tank to check if water is going in Link to comment Share on other sites More sharing options...
ProDave Posted February 1, 2022 Share Posted February 1, 2022 Air lock probably. If a bath mixer tap, put your hand over the outlet and turn on the hot and cold taps and after a lot of gurgling you might blow the air lock through. Link to comment Share on other sites More sharing options...
markharro Posted February 1, 2022 Author Share Posted February 1, 2022 Thanks - tried this with the bath mixer but not getting any noise at all and no progress. Would putting the immersion on and heating the water help in any way? Link to comment Share on other sites More sharing options...
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