For many reasons I have a long run of garden hose exposed to the sun. The water source is always on but the outlet opens and closes intermittently. Some times the water doesn't flow for many hours. On really bright hot days the hose sometimes bursts. Is there an inline pressure relief valve I can put into the hose to prevent the raised pressure from bursting the line? This has happened several times to date.
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1So are you saying there is a valve at the house that closes trapping the supply pressure in the hose and the heat is causing the expansion to the point of rupturing the hose? Or the supply is always on? If the supply is left open and you add a pressure regulator the problem would be if the water pressure increased then it would just run on the ground until the system pressure was reduced possibly costing more than the hose. A bit more info would be helpful but there are “blow off” pressure limiting devices but they may cost more than a few hoses.– Ed BealCommented May 30, 2019 at 13:32
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1I've never had this happen even though I've regularly left my hose on in the sun. Generally there is plenty of stretch in the hose to allow for expansion due to heating. But unless the water is heated to boiling, I can't imagine that the pressure getting all that high. Is your water supply pressure abnormally high to begin with? I think it's more likely that you're starting out with excessively high pressure and then the heating of the hose softens it and causes it to burst.– jwh20Commented May 30, 2019 at 13:32
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1Yeah, there's something else going on here. How is it that the hose is a closed container? The faucet at the house is presumably open, meaning that pressure can be released back upstream.– isherwoodCommented May 30, 2019 at 13:43
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1Have you tried a high quality hose ?– Alaska ManCommented May 30, 2019 at 16:19
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i would use a cheap short hose (3') as a sacrificial "fuse", maybe abrading it beforehand. you might also try shading the run of hose, even with dirt or leaves or old boards or something, it will make a big diff.– dandavisCommented May 30, 2019 at 17:58
1 Answer
Summing up some comments so this question has an answer.
If the hose valve is always on there's no way for pressure to build up inside the hose. If there was an increase in pressure, water would back up into the house plumbing to equalize the pressure. If there was a backflow preventing valve an increase in pressure would cause that valve to drain water until the pressure equalized.
So, the water increasing in pressure is not the issue. The hose material heating up and becoming more flexible is probably the cause. If that is the cause, installing a pressure regulator on the hose could help because it would reduce the starting pressure of the water. In other words, if your hose pressure is at 50psi and that is fine for a cold hose but causes fatigue in a hot hose, then a regulator could bring that pressure down to 30psi. Maybe a hot hose can deal with 30psi just fine.
This would mean less pressure at the point of use and probably less water flow but you didn't state what the hose is for. The best solution is going to be to replace the hose with something more suited to heat and sunlight like an outdoor PEX or UV safe PVC. Something like irrigation pipe is not that expensive.
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1Just to add to this, 100' of 3/4" pex is usually cheaper than high-end 100' hoses. But I wouldn't want to drag it around the yard all the time.– NateCommented Sep 29, 2019 at 6:13