So, after fixing another issue with my grandparents' house plumbing, two days ago, they've now come to me with another issue.
The bathroom sink only has a trickle of hot water and they can't properly wash their hands after they use the toilet. I went and checked and the cold water pressure is fine.. and the hot water works in the bathtub and kitchen. I then went to the basement and felt the line feeding the hot water to that faucet and its warm from the water heater to the faucet, so the line isn't frozen or burst.
Well, I'm not as plumber, so this puzzled the shit out of me.
After some web searching, I came across a real plumber's blog post at: http://www.plumbing-geek.com/clogged-pipes.html
So, now, the game plan will be:
1.) shut off the water valve at the water heater
2.) find some way to plug the bathroom faucet.. either by removing the aerator and placing a dime, paper towel, piece of rubber/silicone or something else behind it.. or finding something else that'll screw into where the aerator was and plug the faucet so that no water can come out.
3.) track down the water lines to find another nearby hot water faucet, preferably the largest nearby line, and turn it all the way open (I'll be using the bath tub)
4.) plug the bottom of the drain at the 2nd faucet so you can visually see what kinds of debris are ejected from it
5.) open the hot water at the clogged line, then open the cold water, all the way.
This should force the cold water back through the clogged hot water line and out the hot water line at the second (bathtub) faucet.. ejecting the rust and scale.
Well, I hope this works. It makes logical sense. I'm not a plumber and I'd really like to avoid having to replace the pipes. My grandparents can't afford to hire anyone else to do it and my aunts, uncle and cousins don't really seem to give a shit
It worked just like the guide said it would. Rust and scale shot out of the tub faucet. Now the bathroom sink has flowing hot water, again.