# corrosion on hot water side



## czplumbing (Nov 24, 2014)

Just seeing if any one can identify what's is going on here. I'll give you a run down of where I am at. Customer has a superstore ss 80gal indirect h/w heater with a resert line. House is five years old and all the pipes just on hot and resert side are corroded and the brass pex fitting are breaking apart? Called super store they said make sure that the unit does not have dielectric unions on it that could be the issue we'll it does not have them. Next I thought let's put a neutralizer on the main cold line so I did but why would the corrosion only appear on the hot water side? Now I am thinking could it be electrolysis? Customer wants me to replace and re-pipe all the hot side lines but not knowing what's causing it and taking the chance it will occur again I may pass on the job. Anyone have an idea of what's going on


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## CTs2p2 (Dec 6, 2011)

Is there a softener? What is the pH of the water? We need some chemistry info..


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## CTs2p2 (Dec 6, 2011)

Also is the recirc controlled via aquastat or timer? And is it L copper?


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## rjbphd (Feb 5, 2010)

Resert?? Same as re circ line?? Pump on re circ line?? If so, what kind and what size? As others said.. that's the ph of water? Private well or city water?..


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## czplumbing (Nov 24, 2014)

I thought low pH was the problem to but if it was a pH issue corrosion would be on the cold side to. It's only on hot side . No water softner in line. Resert meaning circulator running on a aqua Stat 1/2 line pipe off hot water heater is l pipe the rest of the house is pexs


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## czplumbing (Nov 24, 2014)

PH was 6.2. I Installed a 3 cubic ft neutralizer with calcite and corosex


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## rjbphd (Feb 5, 2010)

czplumbing said:


> I thought low pH was the problem to but if it was a pH issue corrosion would be on the cold side to. It's only on hot side . No water softner in line. Resert meaning circulator running on a aqua Stat 1/2 line pipe off hot water heater is l pipe the rest of the house is pexs


The pump is way oversized , causing the velocity corrosion..


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## czplumbing (Nov 24, 2014)

1/2 circulation line. Tell me about the pump how could it corroded if it was to big . Have you come across this problem before?


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## rjbphd (Feb 5, 2010)

czplumbing said:


> 1/2 circulation line. Tell me about the pump how could it corroded if it was to big . Have you come across this problem before?


Many times... what pump u have on the system?


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## wyrickmech (Mar 16, 2013)

Over pumping recirculating line. It will erode the hot and the hot recirculating line until it eats a hole in something. I suggest a product called circuit solver. It regulates the flow based on water temp.


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## HonestPlumb (Jan 25, 2015)

Also, hopefully a brass body recirc pump was used ?


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