What hose arrangement keeps the vapor phase of a low-pressure recovery from dragging on longer than necessary?
Correct Answer
B) Short, large diameter hoses with full port valves
At deep vacuum the pressure difference available to push vapor through a hose is tiny, so any restriction cuts the flow badly. Short hoses of the largest practical diameter with full port valves preserve what little driving pressure there is. Small hoses, long runs and any deliberate restriction can double or triple the job. This is one of the few places where hose selection genuinely changes the outcome instead of just being a matter of convenience.
Why This Is the Correct Answer
Flow resistance rises sharply as hose diameter falls and as length increases, and at deep vacuum there is almost no pressure difference available to overcome it. Short, large bore hoses with unrestricted valves keep the pressure drop small so the recovery machine actually sees the vacuum in the chiller rather than in its own suction line.
Why the Other Options Are Wrong
Option A: Long quarter inch hoses so the vapor has time to condense on the way
Long small bore hoses add resistance exactly where the process can least afford it, and condensing vapor in the hose is not a goal of recovery.
Option C: Standard charging hoses fitted with restrictors to protect the recovery machine
Restrictors reduce flow deliberately. On a job already limited by low vapor density, that is the opposite of what is needed.
Option D: A single hose routed through an ice bath to chill the vapor
Chilling the vapor lowers its pressure further and reduces the driving force. Adding heat to the machine helps; chilling the line does not.
Memory Technique
Big pipe, short run. At near vacuum, every restriction costs you hours.
Reference Hint
Deep vacuum leaves almost no driving pressure, so recovery hoses should be short, large diameter and unrestricted.
More epa-608-type-3 Questions
Some jobs on a chiller count as a major repair under the refrigerant rules, which changes what a technician is allowed to do with a badly leaking machine. Which job falls into that category?
An owner asks how many pounds of refrigerant the rules allow to be left inside a chiller once the recovery has been signed off. What is the correct answer to give him?
The motor of a hermetic centrifugal chiller sits inside the pressure boundary rather than outside it on a shaft. What follows from that construction?
An oxygen monitor is used to decide whether a chiller machine room is safe to enter after a refrigerant release. Below what oxygen reading is the atmosphere treated as oxygen deficient?
A low-pressure chiller's rupture disc has a discharge line running from it. Where does that line have to terminate?
A refrigerant vapor detector in a chiller machine room reaches its alarm level. Besides sounding, what is that alarm expected to do?
Which piece of equipment requires a technician to hold Type III certification before it may be serviced?
What property of the refrigerant is what actually places an appliance into the low-pressure category?
During normal operation, what condition exists inside the evaporator of a running low-pressure centrifugal chiller?
In what unit is the required final recovery vacuum for a low-pressure appliance normally expressed?
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