Suburban IW60 tankless water heater

[Ben Shalom]

Hello everyone, I am replacing my tank water heater with a tankless water heater. Our rig is a 2019 pioneer QB 300 it came with a domatic 6 gallon electric and gas water heater. I am replacing it with a suburban IW 60 tankless water heater. The wiring diagram that came with the suburban unit is not helpful at all for someone who does not understand and has never read a wiring diagram. The wires that came with it are label 12 V positive and 12 V negative, LED lamp positive and negative.

My question is how do I know which wire from the old unit is the 12 V positive and negative? Also, what is this LED lamp positive and negative wires for? Any help is greatly appreciated.

 

[Dahillbilly]

the 12v, dc wires would be connected to the electronic board. The 120VAC wires would be connected to the heater element & over temp sensor both on the tank. Using a volt meter connect one lead to a known good ground then check the wires going to the board make sure your LP switch is in the ON position, the + wire will show voltage. LED lamp wires I'm guessing is just for that to show when it's on.

 

[Ben Shalom]

the 12v, dc wires would be connected to the electronic board. The 120VAC wires would be connected to the heater element & over temp sensor both on the tank. Using a volt meter connect one lead to a known good ground then check the wires going to the board make sure your LP switch is in the ON position, the + wire will show voltage. LED lamp wires I'm guessing is just for that to show when it's on.

Thanks. I will give that a try.

 

[Ben Shalom]

OK, so I was able to find the positive wire coming from the panel in the water heater is working fine with just the positive and ground connections. But now the question is how do I find the negative wire?

 

[david-steph2018]

On a 12VDC system, the negative is the ground. For example, look at your batteries, positive & negative wires. Follow the negative lead, it goes to the trailer frame, AKA ground.

 

[Ben Shalom]

On a 12VDC system, the negative is the ground. For example, look at your batteries, positive & negative wires. Follow the negative lead, it goes to the trailer frame, AKA ground.

Thank you so much for that. makes perfect sense now.👍🏻

 

[Roller4tan]

Typically RV 12v DC ground wires are solid white.