Unvented Cylinder Immersion Heater Replacement

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Morning peeps,

So I need to change the heater element in an unvented cylinder.

Original one on ir test shows dead short to earth so definitely dead. However I've never done one on these new style of cylinder.

Obviously I need to drain it down but has anyone any tips, tricks, advice that may help ?

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I'd be getting a plumber to do that.:)
So would I. That's in a poor state, something has been leaking for a very long time and there is a lot of corrosion, so I would rather someone else broke the tank, not me.

But apart from that, it is no different to any other tank, turn off the water feed, open all the hot taps, then drain down from the drain cock usually with a hose and unscrew the heater, Those last 3 words are the unknown, it will either come out easily, or it will not.

Use the opportinity to do a proper G3 service, which is usually looooong over due, hence another good reason to get a plumber with the G3 ticket to do the job,
 

sirsparkabit

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I got called out to one like that , the bad experience of telling a customer years ago that the tank had split has made me very choosy on ones to attempt and ones to run from.
That ones a definite I am out of here ,next job please .
 

bryanh

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I wouldn't touch it either in the state it's in.

I was always told that you need to crack the Im/heater to just loosen it before draining down as the tank is full and won't flex too much?
 

sirsparkabit

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I wouldn't touch it either in the state it's in.

I was always told that you need to crack the Im/heater to just loosen it before draining down as the tank is full and won't flex too much?
Yes that was always a good tip,however when you get one that won't budge even with a rothensperger box spanner and a long rod for leverage, and then you find some loon put boss white on the thread when it's the gasket that makes the seal ! then you only have one option .
Heat that big brass nut up after draining down and with care and luck it will come undone.
Always hated those ,always issued a warning to customer split tank is on them if it goes wrong .
 

michael8554

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With the tank full, heat and try to slightly tighten first.
This may break the seal, and only distorts the tank in the clockwise direction.
Then anticlock straightens out the tank.
Finally drain and remove the element.
 
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