Rusty water

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I'm getting rusty water from an almost new water heater. (5 months old) Trying to find the cause. The water heater is gas fired with a 2 gallon expansion tank. I called State Water Heater and they suggested that I might have the wrong type of anode rod for the ph of my water. It's an aluminum rod. It's a power vent model 40 gal capacity. They suggested I test the ph of my water with a test kit. 7.5 and higher use magnesium rod, below 7.5 use aluminum. I checked with the water company and they said the water is average 7.3 at the distribution point. I also asked if it could be because of dissolved iron in the water being consumed by iron eating bacteria in the water. They said I could get a test kit to see if there was iron in the water, too. I have not done these tests and I'm not even sure where to get the kits or if it's even worth doing. One web site talked about shock chlorinating the water if this is the case. Haven't done that either.

Then, I suspected it might be the result electrolysis at the unions since they did not have plastic insulators at the top of the unions between the brass adapter and the tightening nut. Anyhow, i opened up the unions and looked inside and found quite a bit of rust caked to the inside of the steel coupling attached to the galvanized steel nipples going into the tank. I called the guy the guy that installed the WH and had him come out to look at it. I told him about the unions and he looked at them. He didn't think that could be the problem given that the tank was so new. I told him about the anode rod. He didn't think that was it either although he did leave a replacement but it was also aluminum. He called State and they said it wasn't covered under warranty since it was a water quality issue. They wouldn't get involved unless I put a water filter in and still had the same problem. He asked if i checked inside of the PRV to see if there was any rust in the strainer. I said no. Later on I opened up the PRV to take a look and it was as clean as whistle aside from a little joint compound. The next thing I checked was the the expansion tank charge and it was at 45 psi down 5 psi from the original charge of 50. So, I pulled off the tank to pump it back up to 50 to match the incoming pressure. Upon examining the tank and T fitting I noticed a good bit of rust. Also, rusty water was coming out of the tank. I called WellSaver and told them about this and asked if the tank could be bad. He suggested that the rust could be a result of electrolysis and said I should put a dielectric connection on it. I never heard of dielectric connections for expansion tanks. But, it did make sense since they are dissimilar metals. Other than that, the tank seemed in good shape. I didn't detect any water coming out of the air valve. The tank didn't seem waterlogged to me. It wasn't very heavy. Just a little water came out. But like I said it was real rusty. When I poked my finger in the tank opening i could feel the bladder pressing against the inside of the tank. And, when I pressed on it a little water would come out.

Another side note. After the wh and tank were installed I discovered the TP valve was leaking. Eventually, I discovered the PRV was bad so I had that replaced. No telling how long it was bad since I didn't have test gauge. (got one now) Anyhow, do you think having the pressure that high may have damaged the tank? (incoming pressure unregulated goes up to 140 psi) Any other thoughts?

Also, I noticed that the static pressure fluctuates from 48 to 58 psi. I'm assuming that's from thermal expansion but I thought the tank was supposed to prevent this. The test gauge is connected to the laundry tub cold tap.

Also, I had the temp control set down to 110 degrees on the WH for a few months before I discovered this problem and since turned it up to 120. Plumber said that shouldn't be an issue. Just trying to cover all the bases. Since that type of iron eating bacteria is said to grow in lower temps. I really don't want to turn it up to 140 for fear of scalding and extra energy use. From what I read 120 is good compromise. Also, the iron eating bacteria is said to be a problem if iron is above .2 ppm I believe. But, like I said, I haven't tested for this. It is also said to grow in temps below 138 degrees. Neither the plumber nor State thought this was likely to be the problem since I'm on city water and they usually treat for iron although they could not give me precise info on this and suggested I test it myself.

Also, I flushed the tank numerous times since discovering this problem last weekend. (flushed not drained completely) The water cleared up pretty good but upon checking it today it seemed a little yellow. When I drain it off with the pressure turned off it seems clear. But, if I flush it with the pressure on it seems a little cloudier (yellow). I'm assuming it's from the cold water inlet stirring up the sediment on the bottom of the tank. Do you think I should completely drain the tank and try to flush out the remaining sediment or do you think it's OK for now and that I should just wait and check it later?

My main concern is with the rust in the expansion tank connection and the dielectric unions. Since, this seems to be the only thing that makes sense at this point

Sorry to keep rambling on here. I've been dealing with this for days and it's wearing me out. I also had to replace the PRV again since I couldn't seem to get it to work right since I disassembled it to check the strainer. (another 75 bucks) The pressure keep creeping up and I discovered a damaged O ring. I replaced the O ring the pressure seemed to be creeping back up again. So, I just replaced it with a Honeywell dial type PRV. The guy at the hardware stored said it was the kind the water company used. Seemed to be a popular item. (65 bucks before taxes plus a compression fitting for 4 bucks, which I didn't need) Seemed a bit pricey but seemed worth the extra expense given the headaches the old one gave me. Looking back on it, the old was probably OK and "pressure creep" might have been due to thermal expansion. Oops! Oh, and learn. Anyway the Honeywell seems to work better (less droop when 2 or more faucets are open than the old one). Pipes are 1/2 inch copper.

Gary Slusser

That's all folks!
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Wherever I park the motorhome.
You are not going to get rusty water from aluminum or manganese anode rods.

I don't know if you mentioned it but the glass lining in the tank is probably broken and the mild steel is rusting. That's if you don't have any galvanized nipples on the heater or fixtures where you see the rusty colored water.

IRB is not tied to the amount of iron in the water although there has to be some iron.

How much iron and hardness is in your cold water?
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