Pocster Posted February 7, 2020 Share Posted February 7, 2020 Had this happen twice on seperate rental properties... ???? Is this common ? Both tanks about 15 years old . It’s an expensive mess when it goes wrong . 2 tanks in 3 months £££££ - donations gratefully welcome Link to comment Share on other sites More sharing options...
ProDave Posted February 7, 2020 Share Posted February 7, 2020 When were they last serviced? in particular the expansion vessels and pressure relief valves? Link to comment Share on other sites More sharing options...
PeterW Posted February 7, 2020 Share Posted February 7, 2020 TPRVs can stick but will usually go at about 6 bar irrespective of the pressure setting. The bigger issue as Dave says is the expansion tanks, and also if the control set has been maintained to ensure the water pressure is below 3 bar. Also, what brand are they ..? And are they stainless ..?? When you say “split” then where is the tank failure ..? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 7, 2020 Share Posted February 7, 2020 My experience has been that expansion tanks need checking annually. We have a few here, including three big ones (two 300 litre and a 100 litre) in the water system. I noticed that the water pump was cycling on and off more rapidly than it should, checked and found all three tanks very low on air pressure. At a guess I've not checked them for maybe three years, and during that time they've gradually lost charge. One thing I noticed on the UFH expansion tank was that the Schrader valve didn't always seal as it should. I changed it for a new one, and as an additional precaution fitted a metal valve cap with a rubber seal. I remember reading somewhere, years ago, that a Schrader valve was only considered to be a secondary seal, and that the primary seal is the dust cap. I'm going to pick up some new metal dust caps this weekend and go around replacing the plastic ones, on the tanks, in the hope that it may help them maintain pressure for longer. 2 Link to comment Share on other sites More sharing options...
Pocster Posted February 7, 2020 Author Share Posted February 7, 2020 40 minutes ago, ProDave said: When were they last serviced? in particular the expansion vessels and pressure relief valves? Who knows . I was always under the believe ( as told to me by multiple plumbers ) that they need no servicing ...... The report from plumber ( as supplied by agent ) says “ariston water heater appears split “ Now says replaced with new stainless steel . Is it possible it wasn’t steel Originally ? ( I haven’t been to the property in 15 years so I certainly can’t remember) Link to comment Share on other sites More sharing options...
Pocster Posted February 7, 2020 Author Share Posted February 7, 2020 I have another flat in the same block with presumably the exact same original tank etc ... Makes me think it’s a bomb waiting to go ..... Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 7, 2020 Share Posted February 7, 2020 If the expansion vessel loses its air charge, then the pressure inside the UVC can rise when it heats up. The expansion vessel is there to do as its name suggests, and allow for this expansion, as water is (as near as dammit) incompressible. Might also be worth checking that the pressure relief valve is fitted and working OK, as if the pressure in the UVC gets too high that is supposed to open to reduce the pressure to a safe level. It's there as a backup for the expansion vessel losing its charge, really, or, perhaps, if the pressure reducing valve on the inlet side fails. 1 Link to comment Share on other sites More sharing options...
Temp Posted February 7, 2020 Share Posted February 7, 2020 11 minutes ago, pocster said: The report from plumber ( as supplied by agent ) says “ariston water heater appears split “ Now says replaced with new stainless steel . Is it possible it wasn’t steel Originally ? ( I haven’t been to the property in 15 years so I certainly can’t remember) They make cylinders in "steel with vitreous enamel lining" and stainless steel. 1 Link to comment Share on other sites More sharing options...
Pocster Posted February 7, 2020 Author Share Posted February 7, 2020 As a precaution have arranged for a plumber to inspect the other flats tank - just in case of issues .... Link to comment Share on other sites More sharing options...
Temp Posted February 7, 2020 Share Posted February 7, 2020 Google found that some have a 25 year warranty. Don't know about your old one but check out if you need to do anything to get that on the new one? Paperwork/receipt from plumber? Link to comment Share on other sites More sharing options...
Pocster Posted February 7, 2020 Author Share Posted February 7, 2020 1 minute ago, Temp said: Google found that some have a 25 year warranty. Don't know about your old one but check out if you need to do anything to get that on the new one? Paperwork/receipt from plumber? Thanks . Emailed agent to get warranty details from plumbing firm ... Link to comment Share on other sites More sharing options...
Pocster Posted February 7, 2020 Author Share Posted February 7, 2020 Uvc ‘s don’t have a pressure gauge though do they ?? - so how do you know there’s an issue ? Link to comment Share on other sites More sharing options...
PeterW Posted February 7, 2020 Share Posted February 7, 2020 40 minutes ago, pocster said: Uvc ‘s don’t have a pressure gauge though do they ?? - so how do you know there’s an issue ? by having it serviced ... insurance company may ask for the service history before they pay out too... 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 7, 2020 Share Posted February 7, 2020 2 hours ago, pocster said: Uvc ‘s don’t have a pressure gauge though do they ?? - so how do you know there’s an issue ? Some pressure reducing valves do have a pressure gauge. The one I originally fitted (before I changed things around so it wasn't needed) had one. Looked like this: 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 7, 2020 Share Posted February 7, 2020 I spent a happy hour draining down our water system accumulators (which are really just the same as very large expansion vessels) this afternoon, and refilling them with air to the right pressure. When doing this I noticed that the label on one mentions the need to check the pre-charge (air) pressure at least every six months. One of the big ones had lost a lot of air, and it took my little 1 1/2hp compressor about ten minutes to get it back up to the 2 bar pre-charge pressure. It looks as if the Schrader valve may well have a very slow leak, so I'm going to replace them all with new ones as well as fit some metal dust caps, with decent rubber seals. I'd not checked these for about 3 years, so it's my fault they have lost a fair bit of air, but it did make me wonder what the recommendations were for checking the expansion vessel on a UVC were. The answer seems to be that all the UK UVC manufacturers I could find, that published servicing details, mandate that their products be serviced annually. Many also make it clear that this annual servicing is required in order for the extended warranty to be valid. My guess is that one of the main things checked during a service will be the expansion vessel pre-charge. 1 Link to comment Share on other sites More sharing options...
Ed Davies Posted February 7, 2020 Share Posted February 7, 2020 I thought UVCs legally required an annual service/safety check. Am I confused (again)? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 7, 2020 Share Posted February 7, 2020 24 minutes ago, Ed Davies said: I thought UVCs legally required an annual service/safety check. Am I confused (again)? From a quick look, it seems that all Part G3 mentions is the installation requirements. In general there's an over riding requirement to comply with the manufacturer's instructions though, and from what I've managed to dig out earlier this evening, these all seem to mandate an annual service. TBH, I thought that Part G3 mandated annual servicing, too, but if it does then I've not been able to find it. 1 Link to comment Share on other sites More sharing options...
A_L Posted February 7, 2020 Share Posted February 7, 2020 37 minutes ago, Ed Davies said: I thought UVCs legally required an annual service/safety check. Am I confused (again)? IIRC it is only a requirement in rented property? 1 Link to comment Share on other sites More sharing options...
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