hi helpers, i want to install an immersion heater as i dont have one and want to have a back up for the gas
so what do i need ?
16 amp mcb for starters ?
its quite a long cable run ( about 35 ft ) so what size cable ?
d/p  13 amp switch pole connection ?
a timer ?
i know you need heat resistant cable to tank !
and of course a heater any sort ???
thanks for your help hopefully

assuming a normal 3KW immersion heater

35 feet thats about 10 meters which isn't really all that far

2.5mm T&E cable should be fine. you could possiblly get away with 1.5mm but its not really worth it.

for the final run to the heater use 1.5mm heat resistant flex.

16A mcb and 13A switcched fused connection unit are fine

if the heater is only for backup use i wouldn't bother with a timer.

now the leccy part has been answered i'm moving this to plumbing so they can tell you how to fit the heater to the tank

Just do what every DIY/Leccy immersion installer does.

remove blank from cylinder, then turn off the water, breaking the gate valve if at all possible. discard fiber washer from immerser and put immerser in hole. Hand tighten 1/8th of a turn as this is where it gets tight. Grip metal cover plate with biggest vice grips/stillsons available, scratching squashing and marking as much as possible(more points can be awarded if you succeed in totally rounding off the big brass straight edges).  tighten home fully so that at least one edge of the immerser is touching the cylinder, there will be a gap on the opposite edge of between 1/4 and 1/2 inch, dont worry about that at this point.  turn water back on(if gate valve still operates).  place old sheets below cylinder to catch cascading water. inspect where leak is coming from, dry off using an old rag and put lots of putty/silicone/instant gasket around the immerser, leave to go off before turning water on again. Wonder why water isnt coming on, turn off mains water and for some reason heating. Call in the plumber to install new cylinder. Stand back and admire work.

btk

haha yeah forgot about those, should also have mentioned that theres no need to worry about the thread the manufacturers put on there, the immerser will find its own path and cut a new thread accordingly.


btk

And make sure that you do not mention that it is better to have the cylinder full of water (other than the top few inches) or the strength of the tank will be lost. MInd if the cylinder was empty then he will get a lovely swirl pattern around the boss for the heater as the copper starts to yield.  Oh what fun I had almost forgotten it

PS - Confession time - I once missed the fact that there was still one of those daft plastic plugs in a redundant (drain pint) tapping.  Phew close call that was.  When I asked for a blanking plug the guy behind the counter asked why a wanted it - My answer was that without it the f'ing water would run out all over the place