@351FUN
If you intend to R&R all these components yourself, take note of this:
One of the functions of the receiver/drier is to remove moisture from the system, as the name implies. To do so, it has a bag of desiccant (think of the silica gel packets you find in certain food packaging) in its base that will filter small amounts of water from the refrigerant. This should be one of the last components you install on the system prior to sealing it, to prevent the desiccant absorbing large quantities of atmospheric moisture and becoming useless. This is doubly true when working with R134a systems, because of the use of PAG oil.
PAG oil is extremely hygroscopic, meaning it absorbs moisture from it's surroundings very quickly. Leaving an R134a system open for any length of time in a humid environment opens up the probability of the PAG absorbing water. So your best bet is to assemble the system as quickly as reasonably possible with a new receiver/drier and fresh oil, and then to pull a long, deep vacuum to vaporize and remove as much of the moisture in the system as possible. This means, ideally, a minimum of two hours at a 29inHg vacuum or more. Below 500 microns, if the machine has a micron gauge. This will remove as much moisture as possible and leave the drier desiccant with plenty of reactivity.
If you use double end capped PAG, it is far less hygroscopic and presents less of a concern for moisture absorbtion, but the concern over the drier remains.
If you intend to R&R all these components yourself, take note of this:
One of the functions of the receiver/drier is to remove moisture from the system, as the name implies. To do so, it has a bag of desiccant (think of the silica gel packets you find in certain food packaging) in its base that will filter small amounts of water from the refrigerant. This should be one of the last components you install on the system prior to sealing it, to prevent the desiccant absorbing large quantities of atmospheric moisture and becoming useless. This is doubly true when working with R134a systems, because of the use of PAG oil.
PAG oil is extremely hygroscopic, meaning it absorbs moisture from it's surroundings very quickly. Leaving an R134a system open for any length of time in a humid environment opens up the probability of the PAG absorbing water. So your best bet is to assemble the system as quickly as reasonably possible with a new receiver/drier and fresh oil, and then to pull a long, deep vacuum to vaporize and remove as much of the moisture in the system as possible. This means, ideally, a minimum of two hours at a 29inHg vacuum or more. Below 500 microns, if the machine has a micron gauge. This will remove as much moisture as possible and leave the drier desiccant with plenty of reactivity.
If you use double end capped PAG, it is far less hygroscopic and presents less of a concern for moisture absorbtion, but the concern over the drier remains.