Our water service was shut off for 3-4 hours.
After it was turned back on several faucets, etc. had air in the lines.
One shower valve only has cold water.
When it is turned to "hot" there is no water as if there is a air lock in the hot water line.
How do we vent/remove the air lock ?

Our water service was shut off for 3-4 hours.
After it was turned back on several faucets, etc. had air in the lines.
One shower valve only has cold water.
when it is turned to "hot" there is no water as if there is a air lock in the hot water line.
How do we vent/remove the air lock ?

You don't because what you have isn't air lock. You have crud or trash that has been pulled up into the hot water side of your faucet and is now blocking it. Turn off the water to the faucet and pull the cartridge. Check and clear the hotwater inlet ports. Now with the faucet still open turn on the hot water and flush out the hot water supply. You should have a full stream if hot water out the open faucet. Reassemble and test. Better now? Tom