MC-601-W Temperature Controller

The controller installs easily and works well. I wish I had known that I would have to spend another $150 to buy this controller when I bought the Rennai tankless water heater. It was not clear on the water heater page that it was necessary to buy this in addition to the water heater. I'm happy with the system, but still in shock that I had to shell out the additional money on top of an already expensive heater.

I had to call customer support to learn how to hook it up. It's not difficult and actually very easy but you just can't know and don't want to risk damaging anything. Customer support was flawless and the guy admitted the instructions are lacking. You'll need this to control the tankless water heater that doesn't come with a controller.

You will have to spend another $150 to get the power switch and then connect it . Also this item must be installed out side .Instructions are very hard to locate where to hook up the wires . I would just spend the extra money and get one with everything included

I got to the point in the installation guide for the tankless water heater and saw where it says install this controller, which wasn't included... and found myself annoyed. They don't tell you when they sell you the WH you need it. So, I contacted Rinnai - they take their sweet time responding BTW.. but the rep said you don't have to install a controller. So I didn't. The WH works fine without it. They should put the word optional in the installation instructions for it.