With a wrench carefully holding back on the valve body
The "curb stop" is the valve that is on the service from the main into your house. i.e. The 8" main in the street has a saddle tap with your 3/4" service line on it. Within 8 ft of the connection between your service and the main is your curb stop. The curb stop is a valve buried underground. In order to open/close the valve a curb box is placed over the valve. It is essentially a metal tube that lets you open and close the curb stop.
Stop Boiler Valve (or Crown Valve) is installed on an outlet line of a boiler. It's purpose is isolation of a boiler from a downstream steam line. Its position may be either open or close, it cannot be used for throttling of steam.
A curb stop is the valve which the city or municipality has installed to turn the water service off and on to a building . Some private systems also have curb stops installed if there are multiple buildings on a common well or water service a curb stop box refers to the enclosure which houses the actual valve most curb stop boxes are not boxes at all but cast iron housings with a pipe that extends to the ground level with a removable cover the valve is accessed with a special wrench which is slid down the pipe and turns the valve off and on.
It is a stop valve placed on an auxiliary piece of equipment. Or it could be placed at the steam main to feed an auxiliary steam system (heating, auxiliary pumping. etc.). It is not the Main steam stop for the boiler or the prime mover (engine, turbine, process), it is for a secondary service.
By installing a GLOBE valve to throttle down the volume
You have to disassemble the valve and replace the springs and cup seals, and maybe the ball.
You must remove the evaporator case from behind the glovebox and disassemble it. The expansion valve is mounted to the evaporator.
By shutting off a valve before it before attempting any repairs then it would depend on what type of valve your talking about globe/ gate / ball as each one is totally different
The Gate valve is the stop valve & the Globe valve is the fluid Regulating valve.
The function of steam stop valve to supply steam to steam maniform and the function safety valve to prevent the steam high pressure over.
You need to recover the refrigerant. Remove the evaporator case and disassemble it. Replace the valve and recharge the system. It is best to install a receiver drier at the same time.
Stop Valve Key
Fit a new valve stem.
Control valve stop valve inch type valve
Back water valve
close it with a valve wrench, change the o-ring
Used in power generation. When steam turbine is on-line the Main Steam Stop Valve is fully open. When offline it is closed. Steam to turbine is controlled thru control valves after Main Steam Stop Valve