Help installing tankless water heater

[RNtoNP]

Any help would be greatly appreciated. I removed the water heater from my 2012 Palomino Puma and am installing a Fogatti tankless Propane one. When I removed the Dometic one that was In there, there were three wires coming from RV to tank. They are Blue, Purple, and white.
The Fogatti has four wires, two blue (which are supposed to connect to the wired control panel), one Red and one Black.
The RED is supposed to go to RV 12v POS and the BLACK is to go to RV 12v NEG.
Does anyone know which of the RV wires is 12v positive, etc ?
I’ll try to attach photo of Back of new tank.
It’s hard when you’re colorblind.
** I just used my voltmeter and got 13v from purple wire, 29 mv from Blue and nothing from white.

[Bama Rambler]

If you take your meter and check between white and purple you should also get 12+ volts.

If that's the case the purple wire is +12v, the white is negative/ground (zero volts) and the blue wire is for the indicator light inside the RV.

[RNtoNP]

Thank you. I will check that tomorrow. And if that’s the case, then where do I connect the blue light, to the 12 v + along with the purple ?

[Bama Rambler]

For the tankless you don't need the blue. Just cap it off.

[RNtoNP]

Man. I thank you so much. I’ll go try today and see what happens. And another thing I learned is how there’s no universal 3/8 inch propane fitting because the RV fitting won’t fit on the new tank and I fiddled with it for 20 minutes before giving up. Weirdest crap I’ve ever heard of.

[RNtoNP]

I’m getting 13.4 v between purple and white. Is that too much ? Should be My last question for you and I sure appreciate it immensely

[Scrapper]

Originally Posted by RNtoNP

Man. I thank you so much. I’ll go try today and see what happens. And another thing I learned is how there’s no universal 3/8 inch propane fitting because the RV fitting won’t fit on the new tank and I fiddled with it for 20 minutes before giving up. Weirdest crap I’ve ever heard of.

3/8" flair fitting is a standard size for rv gas appliances. If the hole in your new WH is smaller you can get the appropriate 3/8" flair fitting from a local hardware store. If it's larger you can get a bushing to adapt the original to the hole. Be sure you get yellow teflon tape for gas lines when assembling the fittings.

Originally Posted by RNtoNP

I’m getting 13.4 v between purple and white. Is that too much ? Should be My last question for you and I sure appreciate it immensely

13.4 vdc is the float voltage to your battery from your converter. You will be fine.
Not trying to be harsh on you but since you don't know about the 13.4 vdc float voltage you should check out the links in this Sticky post, https://www.forestriverforums.com/fo...ts-157524.html

[Bama Rambler]

X2 what Scrapper said.

[RNtoNP]

Thank you. Youve both been very helpful.

[DouglasReid]

Are you installing a control panel for the new WH?

If so the installation manual that comes with it will tell you where to connect the blue wires. You may have to extend them and fish them over to wherever you want to install that control panel