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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> immerstion heater https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1118952255 Message started by poshman on Jun 16^th, 2005, 8:41pm

Title: immerstion heater
Post by poshman on Jun 16^th, 2005, 8:41pm

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 :-*

Title: Re: immerstion heater
Post by Lectrician on Jun 16^th, 2005, 8:59pm

Get a plumber to install the immersion heater - he will fit the required type.

You nedd heat resistant 1.5mm 3 core flex (2.5mm is even better!).

2.5mm twin+earth cable will be fine from the CU to the airing cupboard. Use a type B 16amp MCB, and a 20amp DP switch.

A timer is optional, & not really required if your immersion is only a back up. If you do want one, fir this inline to the flex.

I assume you do have a hot water tank!!

Title: Re: immerstion heater
Post by plugwash on Jun 16^th, 2005, 9:03pm

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 ;)

Title: Re: immerstion heater
Post by thescruff on Jun 18^th, 2005, 11:06pm

We aint gonna tell him yet because you haven't told the poster about part P and all that :o :o :o :o :o :o :o

Title: Re: immerstion heater
Post by billythekid on Jun 19^th, 2005, 8:58pm

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

Title: Re: immerstion heater
Post by JerryD on Jun 19^th, 2005, 9:50pm

Your instructions should be printed on every cylinder btk, very useful advice and would save hours of faffing about for joe public. :D

But you omit to mention that a club hammer is essential to get the stillsons to make that last half turn, and it's these little tips that make tho job so much easier and show the difference between the pro and the diy'er. ::)

LOL ;D ;D ;D

::) :o

Title: Re: immerstion heater
Post by billythekid on Jun 19^th, 2005, 10:53pm

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

Title: Re: immerstion heater
Post by JerryD on Jun 20^th, 2005, 6:49pm

wrote on Jun 19^th, 2005, 10:53pm:

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

Another priceless 'trick of the trade', you won't learn these tips in any DIY manual....... ;D

Title: Re: immerstion heater
Post by Ali Butt on Jun 20^th, 2005, 7:44pm

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 ;D

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 ::)

Title: Re: immerstion heater
Post by thescruff on Jun 20^th, 2005, 8:51pm

wrote on Jun 20^th, 2005, 7:44pm:

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 ::)

Classic ;D ;D ;D ;D