Eemax Tankless Electric Water Heater Review

EeMax makes a large line of electric tankless (instant) water heaters. They are primarily meant for heating domestic hot water and are sized to meet demands ranging from 1 bathroom to whole house residential and up to huge industrial sized units. I chose a medium sized one that was specified as suitable for accepting pre-heated incoming water. This type is intended to be a booster or have the heated water re-circulating through it, e.g. to maintain the temperature in a hot tub. I chose this type because I wanted to use it as an electric boiler in my home's heating sytem, replacing the ancient and inefficient coal and oil fired one already here.

I was happy with the customer service I received before the sale (I had a lot of questions). I was also happy with the price, design, apparent quality, ease of installation and the amount of hot water the unit delivered initially.

However, in the first week, 1 of the 2 heating units failed. Several phone calls to their customer service guided me through fairly easy diagnostics and they mailed me a free replacement of the suspected defective part. But that didn't fix it. Then the second heating unit failed with the same symptoms. A different tech at the factory desided it was the main circuit board and sent me free replacements. This time they even over-nighted them. I replaced both the bards and had trouble free heat for the next eight weeks until one of the units failed again. It looks like the same symptoms, but I haven't had a chance yet to verify that, nor to call the factory again. They've been nice and tried to be helpful all along, so I expect they'll offer more free parts (it's under warranty, after all), but this is getting old.

Also worth noting (though it wasn't mentioned in any of their sales literature nor by their reps during my pre-purchase questions) -- it makes our lights flicker. Since ours has 2 heaters in it, it pulls 240V power through 2 pairs of 40 amp circuit breakers. When the incoming water is fairly cool, both heaters are on a lot of the time. But as the returning water gets warmer, they cycle on and off faster and faster, sometimes in unison. When one gets up to around maybe 15 cycles per second it starts to cause a noticable flicker in any lights that are on. When the water is almost hot enough, the flicker speeds up almost fast enough to no longer be noticable -- but not quite. When both are in unison it is strong enough to be pretty annoying, even when fast. At first, 4 of our neighbors also had flickering lights, but the power company installed a new transformer that serves only us. Now ours are not as bad and theirs don't flicker at all.

For these reasons, I am wondering if I chose the right brand. My application may be different enough to think that it would be fine in it's main intended usage. But I am not the only one to use this type of device this way. And 2 reps had opportunities to warn me off in my pre-purchase phone calls. They knew what I planned to do with it, said it would work fine and that I was getting the right size.