Any gotcha's to drain and refill a hotwater tank to replace 2 x immersion heaters?

[GerryB]

My daughter has all electric heating, however, the lower economy 7 immersion has failed (high resistance short to earth).
I received what I consider a ridiculously high quote of over £400 to drain the tank and replace both immersions (upper boost immersion is working but 8 years old so I assume worthwhile replacing at the same time).
I'm a practical diy'er and ex electrician so considering doing it myself. It looks straightforward from the pics to: ensure all electrics are off, shut the cold water feed, open a hot water tap to drain pipes then drain the tank with a hose, but before I do is there any advice you prof's would give? e.g. loosening the immersions before draining, or does anything need to be done at the expansion tank before or after?

 

[ShaunCorbs]

Does that price include to service the unvented?

 

[GerryB]

Does that price include to service the unvented?

No:-

IMMERSION HEATERS
To isolate & disconnect the Electrics to the Immersion Heaters.
To remove & replace the Immersion Heaters.
To re connect all Electrics & fully Test to Commission the new Parts
All Rubbish to be cleared from Site.

 

[ShaunCorbs]

Does seem a bit on the high side best to get another quote / estimate

 

[GerryB]

Does seem a bit on the high side best to get another quote / estimate

I will, but my questions relate to how easy, or not, is it to do myself?

 

[ShaunCorbs]

Depends how tight they are if you feel upto to it it’s down to you

Would replace them with titanium immersion and replace the drain washer aswell

 

[Ben-gee]

Isn’t this a G3 job?

 

[ShaunCorbs]

Technically no as it doesn’t interfere with any safety components

 

[SJB060685]

Unfortunately for you this is an unvented cylinder and only G3 qualified personnel can work on these things, regardless of how confident you feel.

 

[Chester]

Unvented immersion Sod easy to undo compared to the older ones usually cos rely on rubber seal. Make sure you buy the correct type of immersions, the standard ones from screwfix are not the same thread size.

 

[Chester]

Unvented immersion Sod easy to undo compared to the older ones usually cos rely on rubber seal. Make sure you buy the correct type of immersions, the standard ones from screwfix are not the same thread size.

Providing you're qualified

 

[Ric2013]

Technically no as it doesn’t interfere with any safety components

Is that the case? Given that the thermostat in the thermostat could be argued to be a safety component. If you're right it means I once turned down a job unnecessarily...

 

[GerryB]

It's the replies regarding G3 cert that have really helped here. They prompted me to read and become more aware of the safety aspects of unvented cylinders, so I will focus on getting more quotes, include a service as I suspect one has not been done for at least 4 years and specifying titanium immersions.
Thanks all.