Unvented investigating

[silver50]

Ariston Aquabravo ITD unvented. 5 yrs old. The lower element wasn’t heating so had the spark who installed it all investigate today.

He thought the ‘stat was daffy ducked but actually it had tripped out. Says element testing ok. We kinda knackered ‘stat removing it due to lack of access space so I’ll need another.

I’m in Edinburgh where we don’t get scaling building up so I’m wondering why the ‘stat tripped thinking the element is probably in decent condition.

I’m wondering if I should drain the cylinder so as I personally investigate condition of element/s and take it from there? Or should I just get an element/anode/‘stat?

I’d read g3 to work on UV really pertains to installation more than anything, is that right? Ive also read you should be able to drain/fill without losing vessel pressure so you’re highly unlikely to do anything dangerous.

Don’t want to start sp***ing (spending money up the wall on investigations/time looking at this. It’s a pest the three connections on to the cylinder need undone. Need to spin cylinder round a bit to remove stats/elements. Stupid design- safety valve(?) top left, stopped cylinder fitting into space with the immersions free to come out.

 

[ianmcd]

No you can not work on this yourself , and your post proves that you shouldnt be any where near it , get someone qualified to work on it

 

[silver50]

Why does my post prove I shouldn’t be anywhere near it? I’ve a pretty fair understanding of it. To be frank so often I’ve had to keep an eye on what supposed “plumbers” are doing, to a great extent I trust myself more in taking my time and taking care with plumbing jobs.

The electrician that came today is well known to me and someone I trust. He went to withdraw the thermostat but the amount of room made it tricky. More work to move the cylinder if I get someone else in, I was thinking it made sense to get the element or elements out myself. I’m asking situation re qualification (which I know half the guys out there don’t have but DO work on UV) not saying I feel I must refill myself. I’d ideally like to save arranging another appointment prior to getting new parts.

Also feels tricky re electrician or plumber to fix. Many plumbers not great on electrics and of course electricians not plumbers..

 

[terryplumb]

Why didn't the electrician fit a new thermostat ?
Were you experiencing excessively hot temperature domestic hot water , at any time prior to you realising the lower element was not working ?
As Ian said above ,leave working on the UV cylinder to a pro ,with G3 cert. It really isn't wise to diy.
Get the stat changed and see how you go ,unlikely after 5 years that the element is encrusted ,if the electrician has established the elements resistance is OK its likely the stat.

 

[ajstoneservices]

There seems to be masses of room around those stats to allow someone to work on them.

 

[silver50]

Thanks for replies.

It’s a flat I rent out so I don’t know if the hot water went overly hot.

The thermostat is very long, when electrician went to remove it this morning he could only do it by bending it while sliding it out. A new one wouldn’t go in without bending it an awful lot.

The electrician said he was surprised there was no sign of it failing (ie burn marks) but then the two of us ended up seeing it had clicked or tripped, hence wasn’t working. It looks to me a bit like it probably would’ve started working again. Don’t want to re use it now though.

I don’t think there is enough room to get the elements out. Mind you, unlike sliding the long thermostat out I imagine when the whole element is free, you maybe don’t need the same amount room (probably tilt it much more..?)

I am feeling a bit puzzled as to why the thermostat tripped out. As above, I find it hard to explain the element causing it. Maybe thermostat just faulty in some way I suppose.

 

[Bodd]

It’s a flat I rent out so I don’t know if the hot water went overly hot.

You wouldn't work on your gas boiler. (hopefully) this cylinder is a potential bomb and you have to be registered to work on them as you do a gas boiler.

 

[terryplumb]

If the thermostat itself fails ( and anything electrical can of course ) ,it will allow the element to heat continuously ,and the water will get much hotter than its supposed to ,even possibly to boiling point. The cut out is thermal ,and will trip out in this scenario ,cutting off the supply to the element. Hence me asking about excessive tap temp. It only needs to happen once ,and may even go unnoticed ,once tripped it needs investigating and manual re set.

 

[silver50]

Thanks

The electrical side seems ok as in power wise. Erring towards a new element too. I assume it along with new thermostat will sort things ok.

Not asking this re doing it myself, but does it sound feasible the whole element would come out with the limited space more easily than the thermostat did? (my thinking being much more ability to tilt the angle of it once it’s freed)

 

[Harry Bloomfield]

He would probably have been able to just push the button to reset it, without needing to pull it out and wreck it. I suspect, looking at the photo, that stat and element could be installed as one, without the tank needing to be moved at all. Once unscrewed, the whole lot can be turned at much more of an angle. However as other have suggested, you need a G3 to work on it.

 

[silver50]

Yes, I felt myself it probably could’ve been reset. To be fair to him the little pin to reset it is pretty well hidden. He thought there wasn’t one on it prior to pulling it out.

I assume then that it might’ve worked ok again if reset, or is it more likely something was wrong, maybe with the element?

Be good if a new element can go in ok without having to move the cylinder.

 

[Harry Bloomfield]

I assume then that it might’ve worked ok again if reset, or is it more likely something was wrong, maybe with the element?

To me, it suggests there was probably nothing all wrong with the element.

There are two stats combined in the one package - A normal one which can be adjusted for temperature and a second preset one, which cannot be adjusted, which can trip out for safety if it overheats. The possibilities are that either the adjustable stat stuck closed/ was set too high, or that the overheat stat was faulty and tripped in error.

 

[silver50]

Thanks for the informative info. From what you’ve said I guess getting an element too is probably pointless (even if the element needs to come out regarding clearance issue).

Do you agree or think not a bad plan to get an element/anode too?

 

[Harry Bloomfield]

No obvious reason why it might need a new element.

 

[ianmcd]

You keep going on about changing the anode, yet you say it is and ITD model, if it is it does not have an anode.

ITI/ITD/ITSI models have a stainless steel tank and therefore need no protection against corrosion. STD/STI models have an enamelled steel tank and therefore are supplied with magnesium anodes to prevent corrosion of the cylinder tank. It is imperative that the top anode is checked during the annual service and if found to be corroded both anodes should be replaced. Failure to do so will invalidate the warranty of the tank.