Toilet water supply issues

After the thing leaking, replacing the flapper, valve (FLUIDMASTER 400), resealing the tank... it doesn't fill worth a hoot. I checked the valve but the water doesn't shoot up into a cup like the video shows to clean the valve. Barely dribbles out. I'm guessing either the valve to control the water to the toilet is bad or the water supply mixer valve (? not sure of what you call it) to the control valve is not getting thru as it should.
It is an older (80's) adjustable valve that uses the hot water supply to fill the tank. I looked at it and it's corroded, and the cold/hot mix valve on the top broke when I tried to turn it. The concept of using hot water to fill the tank is not really feasible, because the hot water in the line is cold and take a few gallons of running just to get hot, so it doesn't really prevent the tank from sweating in the warmer weather.
Should I just use the cold water supply line to supply the tank?
I'm rather afraid to turn the water to the house off and mess with the hot water line. Is it tied into the hot water baseboard heating system? I don't want to get air in the system since I don't know how to purge the air from the lines... or is it OK as it is separate from the HWBB system?
No, I haven't checked the toilet water supply valve yet for proper flow. Do these things go bad or need repacked?

 

I'd just use the cold supply, for all the reasons you state.

The one you have now won't be tied to the baseboard boiler, just to the water heater.

Disconnect the supply line from the toilet and direct it into a bucket and see if you get good flow there. If not, then you have a blockage somewhere or a valve that isn't open. If it has one of those flexible supply lines, some of them have a leak stopper device at one end that is notorious for getting plugged up.

 

The angle stop valves are notorious for going bad, especially the hot. The washers will break up and go into the supply line. The valves aren't considered repairable. Post a picture for help on changing out the valve.

 

Here's 3 pics... I'm getting very little water flow from the toilet control valve. Is there a way to check/adjust my output from the hot/cold mixer valve that feeds the tcv? i tried turning the cold screw thread and it just broke off...
or would you just replace the tcv? and what is a good/easy way to replace it considering it is the old style copper/chrome pipe and valve?

tcv


mixer


tcv going into flooring

 

Two threads combined on same topic.

 

OK, went to the store and the guy said he did plumbing for years... anyway, he thought most mixing valves had a life span of maybe 20 yrs max, and mine is 35, so he thinks it is best to cap off the hot pipe, then run the cold to the tcv. He said I can get away with using the current tcv, but why not install a whole new assy? I want to build everything to last till after I'm dead, right? I got a shark bit cap and a coupling, and plan to run cpvc from the coupling up thru the floor into the new tcv. Unless someone contradicts this idea here, that's the plan in a couple of days... I never do plumbing on a weekend in case I need a plumber.

 

I’m no expert but it sounds like it should work. I think today the more reliable valves are the modern ¼ turn stop valve. I don’t think with those you would have the problem you are having now with that older style stop valve. I think something like this:

BrassCraft 1/2 in. Nom CPVC Inlet x 3/8 in. O.D. Comp Outlet 1/4-Turn Straight Valve-G2PR14X C1 - The Home Depot