I have a 2007 JayFlight 25RKS and it does not have a tempature setting for our Hot Water Heater. I know this does not help you, but the questions I have for you:
How long did you wait for the water heater heat up the water?
How long did you run the hot water in the faucet?
Our WH takes about 20 - 30 minutes before it gets the water warm. If we wait an hour and run the hot water in the faucet, it takes a few minutes to get the hot water through the lines. When it finally comes through, it is scolding hot. I always need to tell people to use very little hot water or be carefull when washing hands. The hot water is HOT. VERY HOT.
HAPPY CAMPING!! :D
Daryl and Sandy
2013 Eagle 314BDS
2012 Ford F150 Platinum, 4 x 4 Crew Cab with Ecoboost