How to recover liquid Refrigerant with a recovery system

by HVAC Insider on April 23, 2009

How to recover liquid Refrigerant with a recovery system

One of the most common questions we get asked regarding refrigerant recovery or evacuation is how to remove the refrigerant quickly with a recovery system by removing the refrigerant in liquid form.

Whilst there are some recovery systems which can cope with direct liquid recovery, the majority can only be used to remove refrigerant in its gas state, which we all know can take an eternity.

The first thing to say of course is that you should only be working with refrigerants if you are qualified to do so. Please remember that there are some hefty fines available to punish unqualified people from working with refrigerants.

The diagram shows a typical set up for liquid recovery using a refrigerant reclaim / recovery system, we’ll be referring to this during this article.

How to set up for liquid refrigerant evacuation

Note: an easy way to put a sight glass into the yellow hose is to connect the two ports via a manifold gauge, this has the added advantage that it makes it easier to evacuate air from the hoses and recovery cylinder if necessary by using a vacuum pump.

Here’s the procedure:

Safety First – ALWAYS use Eye Protection & Suitable Protective Gloves as minimum protection!

1. Connect the components as show in the diagram, ensure that the recovery cylinder is on some scales so that you know how much is recovered. I always advise using a filter drier on the inlet to the recovery unit to protect the unit. If you intend re-using the refrigerant (there’s a whole other article coming), ensure that a suitable drier is used on the connection from the disabled unit to the high side of the cylinder.

2. If the recovery cylinder is empty, I recommend that it is vacuumed out which can be done using the recovery unit or (I prefer) by using a vacuum pump connected via the manifold gauges, this also causes a vacuum in the rest of the components to improve efficiency.

3. Open the valves on the recovery cylinder and then open the valves on the disable unit so that the gas / liquid enters the cylinder until the pressure equalises.

4. Open the valves on the recovery unit and start the recovery process. The recovery unit will draw vapour off of the top of the recovery cylinder and push it into the disabled unit, this forces the liquid out of the unit and into the recovery cylinder.

5. Keep an eye on the sight glass to ensure that liquid is still being recovered. When the liquid is no longer visible, you can shut the discharge / liquid port on the unit and the recovery cylinder and you should find that the disabled unit is empty.

6. Close the valves on the recovery unit and check to ensure that the system is empty. In some cases, there may be a small amount of gas left in the disabled unit, this can be recovered as vapour / gas by simply using the recovery unit in the conventional way.

The advantage of this method is speed. Generally a double fan condensing unit / system can be recovered in a few minutes using this method

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