How To Wire In A Fogatti Tankless Water Heater With Existing Wiring

Published 06/26/2022

Products Featured in This Question

Digital Multimeter with 42" Long Test Leads - LED Display

(3)

$22.17

Question:

Hello, I have gas and water hooked up. I’m switching from a tanked Atwood water heater to the fogatti tankless. The old Atwood had a white black and ground coming from it looks like the battery going to a box on the tank. Then was four wires coming from it looks like the fuse box going into panel. There is a orange green white and brown. I watched the install video and it said to hook the black to brown and the red to green. Then the controller wires to the blue. I am not getting the controller to turn on. I have the on button on the fogatti panel. And the fuse is good. Any help or advice on the wiring? Thanks,

asked by: Josh

Expert Reply:

It's always best to test the functions of the wires instead of just going off of a video of someone else's wiring because in my experience people love to mix up wires or cut and splice in others and it ends up being quite a mess. The Fogatti RV Tankless Water Heater # LSB64FR has four wires coming out of the back of it:

Red: Power
Black: Ground
Blue: Controller
Blue: Controller

The first step to wiring a water heater is always going to be using a digital multimeter like # PT89ZR to determine which of your current wires is the ground and which is the power, which you already have found. With those out of the way then the next thing to look for is the communication wires. Pull your old thermostat off the way and look at the connections you have. If you only have one wire connected to the controller, like I've seen in the past, then you'll have to run a second wire for the controller.

The two wires on the controller will go to the two blue wires on the water heater, and it won't matter which is tied to which. Hopefully two of the four wires you have are just communication wires but you'll need to confirm that they are just that and not tied into anything else. With the power, ground, and two communication wires properly spliced to their corresponding wires the controller will turn on and allow you to use the water heater.

I have seen some water pump wall switches that also run a wire to turn on the water heater so that could explain the function of one or more of the wires you have.