My Delta type kitchen sink handle is loose and keeps shutting water off. I have to turn it up a lot to keep it going. I could remove Red / Blue plug and do not know what to do beyond to tighten it?

Use the special tool for pulling handles.

i am not sure which cap you refer to. there is a cap just below the handle. turn off the water supply for safety and remove handle then turn the cap counter clockwise. to replace the hose you should only have to disconnect at the handle to the sprayer and the other end at the faucet below the sink. if you wish to remove the faucet then after shutting off the water undo the nut below holding the faucet in place. delta have a good web site where you can see a breakdown of this faucet.

Yes, debris from water heater replacements often breaks lose and gets stuck. The problem could potentially be anywhere between water heater and the faucet. The faucets shut off valves or the Delta faucet cartridge itself. Turn the hot and cold water valves off under the sink and disconnect the water supply lines from the faucet. aim the water supply lines into a bucket and turn the valves on one at a time. If there is a significant reduction in the water pressure and volume on the hot water side, you need to replace the shut off valve. If there is no reduction in water pressure, you need to clean and/or replace the Delta faucet cartridge. Contact Delta to receive free replacement parts.

handle should have an allen screw rite under the handle coverd by a little cap mite have red and blue..shouldnt have to take hose off but that just snaps off from under sink.

Turn the water off at the shut under the sink and open both faucets to drain line. Remove faucet handle and stem and look inside. There's probably something jamming the stem from turning. Remove that and reassemble.

Pry the hot/cold button off the top of the handle. Make sure the water is turned off below the sink.

Under the button should be screws. Remove the screws. Pry the handle off. Remove the stems by lifting then out.

That should give you access to the washers you need to change.

You need to replace the washer on the stem. It's a Delta so it's possible that you have the type where the washer is actually in the very bottom of the manifold instead of on the stem.

well it do or it don't come out if it is old U R better off buying a new, it is the seals that R leaking, then it could B a weld gone bad

turn of both water supply under the sink.
there is a small red/blue plastic cap at about 45 degree to the underside of the handle. you need a allen key screw driver to lossen it, then pull up the handle. unscrew the lock cap on top of the facet body. left out the cartirdge and make sure there are two "O" ring at the butom of the cartridge is out of the focet body. install in reverse.

The red/blue cover just hides the screw that allows you to remove the handle.

Turn off the water :-)

Remove the handle, you will see that part of the faucet is a large half moon nut. sometimes you can loosen these with your hands, but most times you will need a tool. To avoid damaging the finish with the tool, use smooth jaw tools or protect the nut with a thin piece of rubber/cardboard etc between the jaws of the tool and the nut.

You can then remove the ball/stem, the washers and springs.
Replace the stem, washers and springs and reassemble just as you took it apart.
Be carefull that the little "nipple" lines up with the notches properly.

Take care that you know exactly how it came apart and which direction each prt was facing.