Plumbing in the Home/cross flow in building


Hi, I have hot water in cold lines in a building I work at, toilets are even filling with hot water.  It is 99 units and the problem isn't widespread.  I think I have a cross flow going on at some shower valves.  Its the only thing I think it can be after checking valves, re circ lines and such in the boiler room.  Most of the shower valves are Delta 1600 series valves, can these cause a problem with cross flow?  They don't have a cartridge like a Moen, which is a faucet I have experienced cross flow with, therefore I find it hard to believe it could be happening at that delta 1600 bath/shower faucet.

Scott, I agree the Delta's are most likely not the problem. What I suspect is what I have seen quite often, somewhere there is probably a faucet with an attachment on the spout  or shower head neck that has the capability to turn off the flow with out turning off the faucet. One place to check first is all you maintenance mop/slop sinks. There may be a soap or chemical injector system for filling buckets that could be doing it There are personal showers that have shut offs on them that will cause cross flow if left on for long periods. Start where you are noticing the hot water and check nearby fixtures. Unless some waterlines have been changed, this is where I would start my trace


Plumbing in the Home

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Jay Nicholas


Plumbing & Heating (warm air, hot water & steam heat)


40 years in the business, 35 years as a lic. master plumber in NY State. Retired

Graduated Magna cum laude at the School of Hard Knocks

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Commercial, residential and light industrial. You name it ...I have probably worked on it

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