Greatest Practices For Charging With Liquid Refrigerant

A refrigerant mix is 2 or extra refrigerants blended collectively to kind a brand new refrigerant. All 400 Sequence refrigerants (e.g., R-404A, R-448A, R-449A) are categorised as blended refrigerants. One of many properties of blended refrigerants is that once they change state from a liquid to a vapor, every of its elements evaporates at totally different charges, inflicting the composition to be altered in the course of the part change. Not all 400 Sequence refrigerants behave the identical; for some, the composition change is extreme, and for others, much less so.

Right now it’s common observe to take away a 400 Sequence refrigerant from a cylinder in its liquid part to forestall a possible change to its composition. Including liquid refrigerant to an working system can current a difficulty for a service technician. On some programs, the one low-side entry port accessible is straight on the compressor physique. Including liquid refrigerant at this location or some other low-side port can result in bearing washout or liquid refrigerant getting into the compression chamber of the compressor, each of which might trigger inside compressor injury.

When including liquid refrigerant at this location — or any low-side entry — it is strongly recommended to slowly throttle within the refrigerant. There are adapters accessible that may be added to a refrigerant cylinder to permit the refrigerant to be metered because it leaves the cylinder. Some technicians will use the valve on their manifold gauge to throttle within the refrigerant. They are going to partially open the valve to permit the refrigerant stress feeding the low facet to be about 10 psi above the present working suction stress. They are going to then steadily shut the valve to keep away from introducing an extreme quantity of saturated or liquid refrigerant into the system without delay. Care have to be taken when utilizing this technique, as it’s doable so as to add an excessive amount of saturated or liquid refrigerant into the compressor and trigger compressor injury.

On programs with a receiver and king valve, there may be an alternate technique of including liquid refrigerant on to a system. With the system working, entrance seat the king valve and add liquid refrigerant straight into the liquid line. With the king valve entrance seated, the liquid line stress will drop beneath the refrigerant stress within the cylinder, permitting liquid refrigerant to straight enter the liquid line. A comparatively great amount of liquid can rapidly be added to the system utilizing this technique; nonetheless, it will likely be tough to find out when sufficient refrigerant has been added. You will have to steadily cease the charging, put the king valve again to a mid-seated place, and permit the system to function to a gentle state earlier than measuring the subcooling stage of the refrigerant leaving the condenser. If the system has a liquid line sight glass, it’s also possible to use it as a information, however it’s best to depend on condenser subcooling for an correct cost.

There are a number of variables to think about when including liquid refrigerant to an working system. Not each system is similar, so one technique won’t work on each system. At all times assume earlier than including the liquid refrigerant into an working system to make sure you’ll not trigger any compressor injury.