a/c service procedures section 1

in-line and process

what are the two main types of service valves?

common, line, gauge

what are the three ports in the body of the in-line service valve?

stem seal

what provides the leakproof seal around the valve stem?

front seat (closed, clockwise) and back seat (open, counterclockwise)

what are the two seating positions of the in-line service valve?


in what direction must the valve stem be turned to move the valve from the back-seat (open) to the front-seat (closed) position?

from the common port through the line port with the gauge port closed, normal operating position

when the service valve is placed in the back-seat (open) position, wht is the refrigerant flow pattern?

from the common port through the line port with the gauge port open, service position

what is the refrigerant flow when the valve is placed in the cracked position?

flow is stopped with gauge port open to the line port, position from the factory

in the front-seat position, what path will the refrigerant take through the valve?

access valve

what is another name for a schrader valve?


the schrader valve is also found on what automotive part?

open and closed

what are the two positions of the schrader valve?

valve core is depressed

how is the schrader valve opened?

hose is equipped with a valve core depressor

how does the gauge hose accomplish opening the schrader valve?

two position in-line valve, newest generation

what type of a valve is the harding valve?

with a 1/16" or 5/16" allen type hex wrench, special adaptor wrench designed to be installed on a standard service valve wrench

how is the harding valve opened and closed?

screwed dirctly to the gauge port which is equipped with a schrader valve

how are gauges installed on harding type valves?

the state of the system, type of service valves that are used

what does connection a gauge set to an a/c system depend on?

backseated, fully open, gauge port closed, normal operating position

what position should the valve stem on a pad mounted in-line service valve be in if the system is operating?

stored in the condensing section

where would you expect to find the refrigerant if the valve stem on the in-line process valve is in the front-seated (closed) position?

blowing a small amount of refrigerant through the hoses before the charging operation is started (de-minimis release)

before charging a system which has in-line service valves, the low-side hoses should be purged. How should the purge be done?

wear gloves, safety glasses, use self-sealing hoses or hoses equipped with shut of valves

how do you avoid discharging refrigerant to the atmosphere or your hands when connecting or disconnecting hose fittings?


back seat means valve is what?


front seat means valve is what?