Anode rod replacement: why drain water?


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Old 01-01-20, 05:49 PM
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Question Anode rod replacement: why drain water?

I am going to replace the anode rod in my water heater with a new rod the same size. Archimedes told us long ago that no more water should be displaced in the process, and it's still true.

Why do all the online instructions always say first to drain 10% or so of the water through the full-stop valve?

I can do this, but it's a bit of pain. Just wondering if it's truly necessary.

Thank you in advance!

Happy New Year.
 
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Old 01-01-20, 06:14 PM
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So the water falling down through the hot pipes upstairs does not come out the anode hole and spill all over the floor.

For an all electric water heater, turn off the power/heat before doing this draining. If you by accident or by inexactness drain too much water, the upper element will burn out when the water heater kicks on.

See water gushing from an open hot faucet upstairs for a whole minute before turning the heat back on.
 
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Old 01-01-20, 07:00 PM
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Thanks! Got it. No "upstairs" per se, but the pipes do go make a jog through the attic crawlspace. You saved me a lot of trouble Allen. Gas heater; I'll just turn it off. Truly appreciate your clear and timely response.
 
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Old 01-02-20, 05:55 AM
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You should be draining some water out of the bottom of the heater about every 6 months anyway to flush out the sediment build up in the bottom of the heater.
 
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Old 01-02-20, 10:23 AM
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Archimedes told us long ago that no more water should be displaced in the process, and it's still true.

I'll bet Archimedes never changed an anode rod. That's a good theory, but reality is you are changing the anode rod probably because the old rod is mostly disintegrated which means the new rod WILL displace more water than the old one. And what Allan said.
 
 

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