Less hot water Rheem 21V40-7
I had a tub full of hot water until approx. 2-3 weeks ago when I noticed that I could only get about half a tub full. Same problem in my daughter's bathroom. I have a gas Rheem 21V40-7 hot water heater and I have been trying to find a manual online for this model - to no avail. I've read about possible problems, i.e. broken dip tube, defective thermostat, etc. I'm pretty much a DIY kind of woman, but without an owners manual, I don't want to attempt to fix this problem. Money is tight since my job was just eliminated so I would like to fix this myself if at all possible. Does anyone have a manual or any advice for me? Thanks.