Plumbing Question

[aussiblue]

The cold water braided stainless flexible hose on our kitchen mixer taps decided to fail Tuesday night just before I retired for the night so I have been forced to contort myself under the kitchen sink clearing up the flood waters and replacing both the hoses. The failed hose was only just (10 days) over 6 years old (the warranty period) and failed in what I thought was an odd way with the threads where it screws in to the brass block fitting at the base of tap head corroding so the hose was blown out of the brass fitting. Picture attached showing the crusty "green snot" on the threads as Eric O from South Main Auto would call it. I was aware that the braided hoses on mixers taps had a limited life and needed to be checked regularly but I was expecting that a failure would more likely be a split hose and start as a detectable pin hole leak.

Obviously while the cold water hose was the one that failed the hot water one wasn't going to be far behind. It was lucky I went to get a glass of water before bed and heard the noise of the leak above that of the adjacent dishwasher so the flooding damage was minimised and mostly contained to the one shelf immediately under the sink. I guess the solenoids on the dishwasher, that is fed from the same cold water pipe under the sink, switching on and off was enough pressure variation to find the weak point. The threads in the brass tap fitting head seem Ok and the new stainless hoses with a 15 year warranty (these https://www.bunnings.com.au/kinetic-...-hose_p0422491) have thread that are several mm longer so hopefully it is fixed for now. Nonetheless, I have also ordered a replacement mixer tap that I will install at my leisure in the warmer weather. It's an earlier model of this tap I think that cost me a lot more at the time (well all of $199.99) https://www.ebay.com.au/itm/12473262...Bk9SR8T80Y-ZZA I wonder if using Loxeal sealant (https://www.bunnings.com.au/loxeal-5...esive_p4920450) on the threads originally was a good or bad thing? In any event, I left the new ones naked.



So the questions to the plumbing experts on the forum are:

a) is this a common failure point?
b) Other than replacing them sooner could I have done anything to prevent this and prevent it happening again?

[Citroënbender]

Dry threads, smear of food grade o-ring grease on the rubber, no anaerobic sealants.

It looks like a marine type failure; de-zincified brass. I’d wonder if a steel fastener in contact nearby was getting wet. Could also be low quality hoses.

[Itsme]

Touch wood never had an issue with mine in the house & caravan, over 12 years for the van and about 15 years for the house.

[aussiblue]

Dry threads, smear of food grade o-ring grease on the rubber, no anaerobic sealants.

It looks like a marine type failure; de-zincified brass. I’d wonder if a steel fastener in contact nearby was getting wet. Could also be low quality hoses.

The O rings were greased with HydroSeal tap grease per installation instructions and the threads had Loxeal sealant (the latter not as instructed so the reason I asked). No steel fasteners anywhere I can see; everything appears to be either brass, stainless or rubber. The insides of the hoses are rusty orange coloured bur not build-up like on the threads; perhaps it down to the extremity hard water we have in WA. Interesting that the hot and cold hoses have different coloured rust on the threads too.

[FoxtrotGolfXray 5.0]

Work colleague had a leak on the first floor bathroom of her holiday house. Sadly, it wasn't holiday time, so the leak wasn't found until substantial damage was done (collapsed first floor roof plaster, flooring, walls etc). She never said how much it cost but the project to carry out repairs took around 18 months. I'm guessing the cost was in the 100s of 1000s.

Root cause? A flexible water hose feeding the sink in the ensuite had failed. The insurance company had the opinion that all flexible water hoses should be changed out at a maximum period of 10 years.

[aussiblue]

Touch wood never had an issue with mine in the house & caravan, over 12 years for the van and about 15 years for the house.

I would change them now. I did have a warning advice from my insurer some years ago that failure of such braided hoses both on mixer taps and toilet cisterns were a major cause of insurance water damage claims and that, in addition to regularly checking them and replacing them when the are out of warranty, the stop taps that feed them should be turned off when you go away on holidays. All new braided hoses I have bought in recent years also have a tag on them with a spave to write the purchase date on and a warning saying: "flexible hoses must be inspected every six months and replaced at the end of the warranty period. If any corrosion freying [SIC I think they mean fraying] or leaks are visible this product must be replaced." I have been checking per this tag, but I really didn't think I would need to unscrew them and examine the hidden threads in the tap body.

[aussiblue]

See https://dstdryer.com.au/australian-c...n-humidifiers/ and https://www.9news.com.au/national/ha...9-041b53dc7f2d and https://www.wfa.com.au/hard-soft-water/ etc Perth has some of the hardest piped water in Australia and also the most conductive. The water authority also had to replace the pipe from the main to my meter a few years ago due to a blockage caused by accumulated corrosion from the main so perhaps that was a contributor too.

[danzvtil]

My plumber doesn’t have a problem with these flex pipes per se, BUT insists you get the ones available from reece and not Bunnings, and replace them every 5 years. I also replace the stop valve at the same time, these freeze up due to lack of use.

[aussiblue]

Perhaps the proximity to the dishwasher comes under "Hydraulic Considerations" in this Plumbers Tech Note from the WA Department of Commerce https://www.commerce.wa.gov.au/sites...s_may_2023.pdf but you would think that most kitchen mixer taps would also share the same feed pipe as the kitchen dishwasher.