craig1410
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 posted on 25/5/07 at 10:02 PM |
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Unvented Hot Water System - Advice.
Hi,
There are usually a few plumbers on the site here so I thought I'd ask a quick question about my unvented Santon hot water system.
My neighbour has just had a bit of a disaster when his pressurised water tank leaked and flooded his house. We have the exact same system and I am
understandably concerned that this might happen to us too. I have heard that there have been a few problems in our estate. My neighbour says that his
tank is leaking from the top but can't determine exactly where from until he removed the tank next week. The damage to his property was quite
considerable.
The system is a Santon unvented system with a 210 litre tank heated indirectly by a gas fired boiler. It produces plenty of hot water and the shower
is great but I am worried about the consequences of a failure of the tank.
Does anyone know how many years a system like this should last? Our house was built in 2001 and is sited in Scotland which should mean fairly soft
water. Also, what sort of maintenance should we be performing (eg. charging the expansion tank with air) and should we replace any parts as a matter
of course?
Any and all advice welcome!
Thanks,
Craig.
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Wadders
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| posted on 25/5/07 at 11:01 PM |
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Unvented cylinders, should really be seviced and inspected anually, they can be potentially quite lethal if they go wrong. I think santons have
between a 10 and 25 year guarantee, but i wouldn't like to try and make a claim, in my experience most manufacturers will wriggle out of
warranties, especially if the service records are not filled in. If its an estate development i can almost guarantee they wont have been
installled/flushed out correctly, thats why you get a large proportion failing at the same time. A local estate near us has the same problem, 6 year
old cylinders leaking like sieves, iv'e changed half a dozen in the last six months.
Al.
Originally posted by craig1410
Hi,
There are usually a few plumbers on the site here so I thought I'd ask a quick question about my unvented Santon hot water system.
My neighbour has just had a bit of a disaster when his pressurised water tank leaked and flooded his house. We have the exact same system and I am
understandably concerned that this might happen to us too. I have heard that there have been a few problems in our estate. My neighbour says that his
tank is leaking from the top but can't determine exactly where from until he removed the tank next week. The damage to his property was quite
considerable.
The system is a Santon unvented system with a 210 litre tank heated indirectly by a gas fired boiler. It produces plenty of hot water and the shower
is great but I am worried about the consequences of a failure of the tank.
Does anyone know how many years a system like this should last? Our house was built in 2001 and is sited in Scotland which should mean fairly soft
water. Also, what sort of maintenance should we be performing (eg. charging the expansion tank with air) and should we replace any parts as a matter
of course?
Any and all advice welcome!
Thanks,
Craig.
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MkIndy7
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| posted on 26/5/07 at 12:21 AM |
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As suggested if its happening to alot of houses on the same estate its likely to be a common instalation problem, such as not cleaning the flux off
the pipework or flushing the system.
A common problem i've come across with some unvented systems is that the expansion vessel fitted is the heating type thats made from Mild steel
(for heating) and not the Potable water type thats made from stainless for changable water conditions.
The expansion vessel should be checked about once a year properly by shutting off the water and draining (or certainly losing the pressure from the
system) then checking the pressure on the Schroder valve and adjusting accordingly. Although periodically a tap on the cylinder with a metal object
will tell you if its air or water in there.
Where/how have the other failed?.. tihs would give vital clues as to what the underlieing problem is.
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craig1410
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| posted on 26/5/07 at 07:05 PM |
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Hi guys,
Thanks for replying.
All I know is that the water cylinder itself is leaking from the top but we won't know more until it is removed on Tuesday. Maybe the expansion
vessel didn't have enough air in it and the over pressure valve malfunctioned? I don't know.
My cylinder is a Santon Premier TP210B and I am told it was installed almost exactly 7 years ago. I have just taken some pics and will post them in a
moment to let you see what my installation looks like. I would certainly appreciate any tips on maintenance and any DIY checks I can make. I tried
tapping the pressure vessel lightly and I think it has air in it but can't be sure.
Thanks,
Craig.
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craig1410
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| posted on 26/5/07 at 07:16 PM |
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Okay I've uploaded some photos to my photo archive in the "Water Tank" folder
here.
I left them full resolution in case you needed to zoom in for detail.
Thanks,
Craig.
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MkIndy7
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| posted on 26/5/07 at 10:07 PM |
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I can't see a leak from any of the photo's.
Even if the expansion vessels are completely flat or burst the specific safely valves would blow off if it went over pressure on either the hot water
or heating side.
Can you not remove the blue cover on the top to see exactly where its leaking from?
Looking at the state of the pipework i'd guess its a soldiered joint thats not had the flux cleaned off.
The only other thing to look out for is the miss-use of fittings/components.
On the Domestic Hot Water side all of the fittings should either be Brass, Copper or Stainless (or I suppose plastic!) as the constantly changeing
water corrodes any other material used such as Iron or galvanised fittings.
Also If you have the instruction manual or have a look on their web-site it may have "Sacrifcial Annodes" in it... These are magnesium
rods that are easier for the water to corrrode than the system components thus saving them... if it had them in 2001 and they've not been
changed since then there likely to have worn out by now (maybe your neighbour uses his more and thus he's found the problem first!)
[Edited on 26/5/07 by MkIndy7]
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craig1410
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| posted on 27/5/07 at 12:23 AM |
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Hi,
Sorry, I've confused you...
The photo's I've posted are of my own system, it's my neighbour who has the leak!  He has had his system inspected and a new tank
is being fabricated for him to be installed on wednesday so I hope that it wasn't just a badly soldered joint! To be honest thought the plumbing
in this (barratt) estate has been a problem before. For 12 months after building the houses the drinking water was contaminated with lead and the
houses were re-plumbed anything up to 3 times before it was resolved. I have also seen a few things under my floors which make me cringe! I'm
not a plumber but in my opinion neither was the guy who plumbed my house!! Flux everywhere, solder everywhere, holes knocked in plaster with a hammer
and bits of left over pipe rattling around. Not to mention pipes not clipped, joists notched out where they shouldn't be, kinked heating pipes
etc etc. A real sh1t job IMHO...
I'm not sure if my system has an anode or not. I have asked Santon technical support for a copy of the installation manual for my system but I
doubt they will supply a householder with this information. I did say in my request that it is for informational purposes and that I had no intention
of messing with the system so they might help me out.
Does anyone have an annual maintenace checklist for this sort of system? Is it a potential DIY job to carry out annual maintenance?
I think I'm going to take out heating cover with someone like Scottish Gas or GasSure and I will make sure the tank is covered. I will also make
sure my house insurance will cover damage caused by my water tank bursting just to be safe.
Thanks again,
Craig.
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MkIndy7
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| posted on 27/5/07 at 11:12 AM |
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Just had a look and there manuals are available on line
http://www.santon.co.uk/santon/santon.nsf
I'm guessing that yours or the closest to it is the Premierplus.
It doesn't look like there's an Annode anywhere in them in the Mainatanace section at the bottom. These are the same instructions that an
engineer would have and use so if you feel pretty competent with a spanner you could do it yourself.
I wouldn't bother with the Cover either.. if you can get hold of a plumber when needed or somebody to service the boiler once a year then
you'd be quids in over the multinational companys cover, they given like 1hr to rush through the servicing of the boiler and inspection on the
cylinder etc (I've even heard of them just sticking a combustion analyser up the flue and thats it!)
There is nothing they can really do to make the Cylinder any safer.. other than giving it a good look over, which you can do yourself, checking for no
small leaks, corrosion (if there is any then clean it off or re-make the joint) etc. The only other way is what they use with industrial pressure
vessels and steam boilers where they test the thickness of the metal with X-rays or something.
The cylinder itself i'm sure i've read is made from stainless steel so it shouldn't be corrosion and they are hydraulicaly pressure
tested before they leve the factory so it shouldn't be a manufacturing fault.
P.s any joints where the copper pipes look green around a joint need wipeing off with either cleaning strips from B&Q etc or the green side of a
pan scourer and wiping off with water if you haven't already.
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craig1410
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| posted on 27/5/07 at 11:26 AM |
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Hi,
Yes I found the PremierPlus installation instructions but my system looks a bit different. I agree the principles are probably the same though so if
Santon can't provide the Premier manual then I'll try to extrapolate the PremierPlus manual.
As for the Anode, I too thought that there wasn't one but after looking at the spare parts page here (
http://www.santon.co.uk/santon/santon.nsf/SparesLookup/PremierPlus/$file/premier.pdf ) I'm not so sure. It shows an anode for the TP210B
indirect which is what mine is. Another reason I would like to see the installation instructions because I wouldn't mind buying a new anode if
required.
I'll clean the joints as recommended. I take it the green corrosion gets progressively worse if I don't? I didn't realise that.
Would I be correct in saying that the safest way to work with the tank would be to cool down the water and release pressure? I'd be quite
nervous of working with it while it was full of scalding water at 3.5 bar pressure... 
Thanks again,
Craig.
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MkIndy7
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| posted on 27/5/07 at 01:11 PM |
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Well spotted that man!
Maybe the older cylinders were glass lined steel and now they've moved on to stainless then (hence them not being in the newer manuals). If this
is the case his cylinder might have been mis-handled or the glass lineing damaged and as soon as the annode has worn away.. or just over time the
changing water has attacked the steel vessel.
The green corrosion is most likely to have been caused by the active flux used in the sodiering process so presumably it would continue eroding the
top layer of copper or create a situation where other things now corrode the copper causing leaks after time.. it certianly shouldn't be there
and for the little time it would take to remove its better to do so.
I'd turn off the boiler and immersion heaters (don't want it to continue trying to warm the empty cylinder).
Close off the Stop tap to the appliance (Should be before the pressure reducing valve)
Run a tap to relieve the pressure and then drain the cylinder using the drain-off cock (to be on the safe side).
Also try and "crack" any joints you need whilst there is still water in as the cylinder as its at its strongest then and won't tend
to move as the weight of the water holds it still.
Looking at the spare parts list/diagram the Annode is actually part of the nipples that the pipes connect to.. i've been told they its usually
the Cold water inlet connection.
Also somewhere in the manuals i've read there maybe a filter/strainer in the cold water pipework to the cylinder.. it would be worth
checking/cleaning that whilst its all drained down.
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