Cold & hot lines are connected on water heater

Old 05-25-24, 11:03 AM
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Cold & hot lines are connected on water heater

I came across the setup below while reading this article here. What's the point of the crossfeed looking tube here between hot & cold lines?


Last edited by PJmax; 05-26-24 at 11:44 AM. Reason: pic hosted/posted PJmax
Old 05-25-24, 11:21 AM
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It's a tempering valve setup. It allows you to set the water heater to a higher temperature and then mixes in cold water so the water distributed is a safe temperature, say 120 degrees. Two main advantages of this. First, running the water heater above 130 degrees prevents legionnaires disease. Second, you extend the amount of usable hot water a little, since making a gallon of 120 degree water uses less than a gallon of 140 degree water.

Current codes in many areas now require tempering valves.
Old 05-26-24, 11:47 AM
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A added some visual references to your picture.
This is predominantly used on an electric water heater with slow recovery.

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