I'm trying to find out what water heaters work.best for a replacement water heater. I have read that on demand hot water sacrifices pressure and honestly I would prefer the LP/120V option I currently have but I believe the one I have is the original one and I cant find anything on the unit itself. Any suggestions?
Your 1989 GV most likely has a Atwood water heater...either 6 or 10 gallon. Could be gas, or gas + electric, and may have MotorAid option.
MotorAid option circulates hot engine coolant around the water heater tank so you have hot water available when you arrive at destination.
We have a excellent "Search" tool on this Forum, located at the top right corner of every page. By doing a quick search here you can often find the exact info you seek. Saves you time, and you learn a lot of interesting stuff about your coach. For instance:
Replacing Atwood Water Heater (https://www.foreforums.com/index.php?topic=38968)
Has anyone done any work on an Atwood? The electric doesnt warm the water. The switch is below the bed at the foot...it turns on but the water isnt staying hot. The LP is also cycling a lot. Is there a way to.fix it without replacing it? Looks like about a $700 unit.
You need to do some trouble shooting. Will require a good quality digital multimeter and common sense.
First, be sure when you turn ON the switch on at the base of the bed that it is actually the switch for the water heater. Some Foretravel coaches have a engine block heater that is controlled by a red switch at the base of the bed. This has caused confusion in the past.
If your coach is similar to ours, there should also be a water heater switch somewhere near your kitchen sink. It should have two LEDs. One is a power-on indicator, and one indicates successful ignition of the propane flame.
If you are sure the switch is for the water heater, turn it on and use your multimeter - check to be sure power is actually getting to the water heater.
First link below to general guidence. Second link to a list of factory manuals. If you can determine the exact model of your water heater, then you can download the specific manual which should include a trouble shooting section.
Atwood Water Heater Troubleshooting (http://web.archive.org/web/20191218121913/http://www.beamalarm.com/Documents/atwood_water_heater_troubleshooting.html)
Atwood Water Heater User Manuals Download | ManualsLib (https://www.manualslib.com/brand/atwood/water-heater.html)
If you determine that your water heater circuit board is faulty, you can purchase a EXCELLENT replacement board from Dinosaur.
Ignitor Board Index page (https://www.dinosaurelectronics.com/Ignitor_boards.htm)
I've done work on our Atwood water heater and it's not hard. Chuck has the right links. Dinosaur does make excellent boards but after replacing one, it has about a 10 second delay before the gas flows. You did not have a 110V heater on your OEM water heater. Some had "hot rods" installed and then there would be a switch. The switch at the foot of the bed is for the block heater on the engine unless someone added an additional switch. The after market 110V heaters usually have the switch install above the water heater. Ours is in a bathroom compartment only a couple feet above the heater. Sensor kits are cheap for the heater also. Clean all electrical contacts until bright.
Pierce
My wife just reminded me - the last time we were out our hot water heater quit working on propane. I did a bit of trouble shooting and found the thermal cutout fuse had failed. Simple to check - remove the fuse and use the continuity testing selection on the multimeter. If it shows a open circuit than it is failed.
How To Use A Multimeter - iFixit Repair Guide (https://www.ifixit.com/Guide/How+To+Use+A+Multimeter/25632#s64987)
Should be able to buy the Atwood kit at most RV supply stores or online. See below for example:
Amazon.com: Atwood 93866 OEM RV Water Heater Thermal Cutoff Kit - Replacement... (https://www.amazon.com/Atwood-93866-Heater-Thermal-Cutoff/dp/B077YR29HL)