Pressure relief valve

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Hi all,
I'm looking at fitting an unvented electric water heater in a ground floor cupboard to replace an old immersion tank. Might fit a Hyco Powerflow or an Eldom if they're any good. ?
Anyway, as the cupboard is in the centre of the house there is no way to run a discharge pipe other than upwards into the loft. Is it permissable to have the pressure relief valve connected to a pipe which goes up into the loft and then out the soffit or does there have to be a tundish next to the boiler? Any advice appreciated.
 
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Sorry but you cant do this work yourself, you require an Engineer or plumber holding G3 certification and they will advise the best route
 
Thanks for the advice. I intend on doing most of the work myself. Just need to know whether I can vent the valve into the loft without a tundish.
 
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You will not be told , you can not do any part of this work yourself , YOU MUST BE G3 qualified
 
Unvented cylinders are rockets waiting to go off. If there's an uncontrolled overheat in the cylinder and the pressure relief valves aren't functioning correctly, it will explode and happily head up through whatever is above it.

There is nothing about an unvented cylinder that you can do yourself and any decent qualified professional will not sign off anything he hasn't installed himself.

A well shared video showing what happens when there's a failure of an unvented cylinder
 
remind me, how many times has that happened, in an ordinary domestic installation, in an ordinary UK house, in the last ten years?
 
A well shared video showing what happens when there's a failure of an unvented cylinder

Because the test building has no walls the explosive pressure wave from the bleve passes harmlessly out of the building. If the building has walls then the explosive force could cause then to collapse

bleve = boiling liquid expanding vapor explosion
 
I could show numerous videos of engines literally exploding on test beds or on rolling roads but I’ve never seen it in a real life situation and I’ve never heard of it happening either. Doesn’t stop people over revving their engines though. I suppose you could set up any situation to show the worse possible scenario.
 
Tundishes are there for a reason!
My tundish is in my airing cupboard. How often am I supposed to check it - every month, week, day, hour, 5 minutes? Perhaps some audible warning device would be better?
 
This isn't about how many times it has happened, this is all about there being a chance, however small, that it could.

If there's any risk at all that something in my house could explode due to incorrect installation, then that's too high a risk.

That's why it's notifiable and the person needs to be qualified, simples. Sometime it takes a view of the worst case scenario to stop someone from doing something they shouldn't.
 

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