[davismltc]

Wow, last post to this thread was 3 years ago! Where are all the hackers? On to bigger and better I suppose...

I'm new to the ecorenovator site and as an A7 owner, I thought I might share my experiences. I bought an A7 HWHP (new) off ebay and installed it on top of my electric HWH in my basement. A friend was helping me install it and through miscommunication the copper lines being fed into the tank weren't fed into the brass fitting correctly and the lines had to be removed. Removing the lines from the tank was awkward at best. Once the error was corrected, the rest of the installation went smoothly.

The unit worked great for a little over a year, and the HWH tank failed. I assumed the failure was caused by us possibly scratching the glass lining of the steel tank when we attempted to remove the copper lines during the initial installation error. The sacrificial zinc was still in pretty good shape.

I purchased a new electric HWH and was able to install the A7 without any problem. This time I was very careful about feeding the copper lines into the tank. A little over a year later the second tank failed, and I must say the sacrificial zinc had been doing its job and there was plenty of zinc still left.

I was about to give up on the whole HPWH when I got an idea on how to stop the corrosion problem. I decided to route the 1/4" heating lines into some 1" cpvc and create a heating 'U' loop instead of placing them inside the tank. Ebay provided me with a used brass Taco circulation pump. So now my (insulated) heating loop is outside my hot water tank and isolated from the glass lined steel tank. I use a digital thermostat (probe is snuggled against the hot water tank) to turn the heat pump and the Taco circulation pump on/off to maintain the desired temperature in the tank. My heating loop is insulated and strapped to the ceiling of my basement. I'm now going on year three without a tank failure.

As I side note, I rigged up some CPVC fittings so water for my heating 'U' loop is pulled and returned from the same fitting and it is installed where the tank drain was previously. Water is now pulled from the very bottom of the tank and heated water is returned there as well. I wanted to be sure I didn't induce any heat siphoning, and my 240v heating elements remain in the glass lined tank for backup. All I have to do is flip the breaker on...which I haven't had to do since the unit was installed.

I'm just wondering if anyone else has experienced problems with galvanic corrosion because of all the copper tubing introduced into the glass lined tank? I previously had zero problems with my power hungry resistance hot water heaters.

Thanks to all for their contributions....this site ROCKS!!