Discolored hot water / HTP PH 76-60 hot water heater installed 5 months ago

barbap

Hi! I'm just a homeowner looking for help! Five months ago we had an HTP Phoenix 76-60 stainless steel hot water heater installed, but only about a week ago we started seeing discolored hot water (pale yellow-green) when running a bath. Cold water was clear. We have a whole house sediment filter which was changed out five months ago, and a Hague water softener, which was set to less than 1 grain at the time…

We drained our hot water heater as best as we could by filling the tub a couple of times, hoping to flush out whatever was discoloring the water. The color faded, but returned the next day.

We Googled and saw that possibly lowering the temperature of our hot water heater could help, so we took it down from 140 to 126 degrees. We also cleaned our water softener beads with Iron Out and did a regen. Calling up HTP yielded the advice to add more grains of hardness to our softened water. Luckily our softener has a mixing valve, so we raised it up to 5 grains, their minimum hardness recommendation.

We called up our town's water department and they confirmed that there have been no recent maintenance events, and reassured me that pH and chloride tests are all within spec.

All of these initial changes didn't make a difference, so we ordered up many water testing kits. Here are our stats:

pH: >7.6 (as high as our test could go, but was told that our town has been testing at 7.7 for forty years)
COPPER: Softened cold water: 0.0 ppm / Softened hot water: 0.1 ppm
CHLORINE: Municipal tap: 0.3 ppm / Softened water: 0.05 ppm
IRON: Municipal tap: 0.3 ppm / Softened cold water: 0.12 ppm / Softened hot water: 0.6 ppm (double the municipal feed)

So we’re assuming the yellowish-green color is from iron and a little bit of copper somewhere in between the stainless steel hot water heater and our tap. But what could be causing this?

Calling HTP again, they swore that we must have some galvanized pipes somewhere in our system, causing the corrosion to the stainless steel. Our system is all copper. We do have some aluminum clamps with zinc screws, but they said that shouldn’t affect our water.

Another thing HTP guessed was that the soft water could be reacting with the cupronickel coil. Is this likely? How delicate are these stainless steel units?

What we don’t want is water harmful to bathe in, or corrosion to our hot water heater elements or tank, or our pipes!

Does anyone have any insights? @Larry Weingarten — I see you mentioned on this forum for good advice? I would be so grateful! Thanks in advance?

hot_rod

how did you test the chloride level, what is that number? What is the HTP limit?

Chlorine level tested with color strips?

Jamie Hall

Well, the colour strongly suggests mostly copper, with a little iron possibly mixed in.

That said… I see you measured Chlorine — a water treatment disinfectant — but not Chloride, which is only one letter different but chemically very different. And, unfortunately, a byproduct of any type of ion exchange water softener, and can be very corrosive on some types of stainless steel, as well as copper pipes. That may be your problem.

mattmia2

depending on the model, some htp indirects have a copper nickel hx, that is probably dissolving. could be the over softened water, cold be some stray current in the plumbing or probably both.

100 ppm is htp's limit on chlorides, at least on my ~2019 superstore.

Larry Weingarten

Hi, I would stop softening the hot water complely and see what difference it makes. Stainless and salt don't get along at all! I've seen recommendation from the National Association of Corrosion Engineers that you leave 60 to 120 ppm of calcium and magnesium hardness in the water after softening. Otherwise it can damage even copper pipe.

I'd be tempted to drain out the softened water and refill with unsoftened, to give you a good start on identifying the problem. 😉

Yours, Larry

hot_rod

This is how an ion exchange water softener works.