how to replace an immersion heater?

[bluesky]

a customer's immersion heater is gone, i am thinking to get a new one, but i am not good at heating system, checked books, i need to drain the cylinder first, this is a vented system, 2 tanks in the loft, how to drain the cylinder? cannot find gateway to the cylinder, anyone has experience?


cheers in advance

 

[Guest123]

If there are no isolation valves on the pipework coming from the tanks to the cylinder (usually red cartwheel type ones), tie up the ball valve in the loft to stop the cylinder refilling when you start draining down.

There'll be a drain valve, normally at the very bottom of the cylinder that you can slide a hosepipe on to, to drain off the top couple of inches (you dont need to drain the whole tank) if it's a top (backup) immersion. Obviously if it's an E7 bottom immersion then you will have to drain the whole cylinder.

One thing, slacken off the immersion a little before you start draining down with a decent immersion spanner, as the cylinder is stronger when it's full of water and there's less chance of you tearing the ridiculously thin copper that the immersion screws into.

Make sure you clean the collar of the cylinder where the immersion screws in with wire wool and sandpaper to get rid of the old gasket and/or paste, a little PTFE on the new immersion with the new gasket will be fine (always handy to have some plumbers jointing compound handy though) just incase.

 

[Sintra]

And an immersion heater spanner.


www.toolbank.com | Immersion Heater Spanners

 

[bluesky]

cheers guys

 

[UNG]

A few of the tricks I've used

If there are no isolation valves on the tank or the one that is fitted has seen better days I reach into the header tank and put a rubber bung (or anything that blocks the outlet, I have used a wine bottle stopper before now) in the outlet pipe to the hot water tank to save time draining down. I sometimes fit a valve if I have one with me put's a bit extra on the bill and is peace of mind for the customer as they can isolate the water if they have a burst

If the hot water tank has no drain cock I open a hot water tap upstairs and one downstairs to drain off the hot water in the pipes then disconnect the hot water outlet on the top of the tank (put an old towel round the top of the tank to catch the small amount of water left in the pipe) and then use a short length of hose syphon out the water into a bucket until it is below the level of the immersion heater

 

[caddy]

One thing, slacken off the immersion a little before you start draining down with a decent immersion spanner, as the cylinder is stronger when it's full of water and there's less chance of you tearing the ridiculously thin copper that the immersion screws into.

Pay special attention to what Lenny has said, be sure to slightly loosen the old one first. If it is really tight it often helps to give the spanner a few sharp hits with a hammer rather then trying to apply constant preasure. If its still to tight you can try heating the collar with a blow torch. Better to go prepared and not use it then not take one and need it.

And be sure to close the drain off valve before refilling the tank

 

[bluesky]

thanks for your tricks, UNG, believe you are good at plumbing as well besides electrics

 

[UNG]

Did quite a bit of plumbing back in the late 80's when trades were in short supply as they were kept very busy. My business partner at the time priced some jobs where we supplied all the services installations using subbies if needed, problem was on a few jobs the plumber let us down causing a major panic for my business partner so I did the plumbing

One customer at the end of his job was quite curious how the plumber (me) fixed the fire alarm when the electricians were having problems sorting it

At the moment I keep getting asked to do bathroom refits having done a few for friends word of mouth is spreading, I've even been asked to move a radiator on a kitchen rewire

 

[robsparx]

Customer wants me to replace an immersion today. I have NO idea about plumbing whatsoever. The only experience I've had with it is drilling through a central heating pipe a few months ago!

I've drained down central heating before, but that's it. Think i might be best just getting a plumber in to do it??! Really dont like messing around with things that I have no idea about

 

[ut1dot]

Too add to the fun! once your done you might find you have an air lock (which really makes you smile)

How to fix an airlock the hose and taps method is good.

 

[Gavin121]

The immersion heater is the heating element that is situated in your hot water tank. It is easy to identify. The exposed part looks like an upturned cup and can be found at the top of the tank (top entry) or at the side of the tank (side entry). In most households the hot water is also heated via a heating coil from the boiler with the immersion just a back up. In houses with economy 7 or 10 electrical heating the immersion is the only way to heat your hot water. Regardless of system, the immersion heater is an important component and should be changed as soon as it fails. If you need a new one, Screwfix is as good as any other supplier.

 

[telectrix]

be sure to go for the non corrode type, a few quid more but will last a lot longer.

 

[jpmiff]

Hi

i always fit a new thermostat as well!

 

[telectrix]

So do i

 

[Spudnik]

I always get the plumber to do them