On your water heater, I'm going out on a limb here, but this one may be what was originally in the camper. An all gas, pilot light, Atwood 6 gallon water heater model G6A-7P part number 96110. They may have up'ed the rev level on a brand new one.
Etrailer has good pics of the unit. You can shop around on price but they are competitive and free freight.
If wanted, you can upgrade to an electronic spark ignition with a electric element option. You would need to run 12 volt DC control wires to turn it on and off and 120 VAC power to run the electric element. They also offer electronic spark ignition but no 120 VAC electric element. Most times these options cost a little more than the all gas one you most likely have.
The furnace, I'm not sure what yours would have other them it would of originally been an Atwood Hydroflame furnace. They use to use a 7900 or 8000 series furnace on the older smaller campers. They looked like this,
But there are different BTU sizes and vintages of them on how they light the burner.
Dometic bought out Atwood a few years back and I'm not seeing anything new on their website that looks like the older 79 /80 series furnaces. They do offer lower BTU units, but the shape if different. https://www.dometic.com/en-us/us/pro...furnaces?at=rv
If you can give us the make and model number of both the water heater and the furnace, we can try and help better. We have no idea if someone changed it over the years and or what is exactly in your camper. The water heater make/model would be on a sticker outside behind the drop down cover. Assuming you can still read it.
The furnace make and model tag will be behind the outside cover.
Taking pictures and posting them of the units really helps show us what you are up against.
That said, parts are available in many cases and may still be available for the make/model you have if you cannot find a new unit or the cost to replace is too high for you.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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