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You are here : Home > Services > FROZY’s advice > Cleaning of polluted refrigeration installations
Cleaning of polluted refrigeration installations

The cleaning of polluted refrigeration installations

The use of a cleaning fluid must follow a specific procedure, generally quite complex.
The use of a cleaning fluid often requires dismantling of some components of the installation, removal and replacement of refrigerant.
This kind of operation generates a long break of the installations, often incompatible with the good running of the facility.
Simple and inexpensive solutions exist and allow to solve most of the problems encountered on site.
- Without causing long stops of the installations
- Without replacing systematically the refrigerant or oil.

Cleaning filters and cores, called “burn-out”, can meet the refrigeration engineers expectations.
These filters contain chemical agents which allow simultaneously: acid neutralization, particle filtering, catch of moisture, catch of waxes and sludges created by the decomposition of oils.

How to use those filters?
For each sort of pollution, CARLY offers an adapted product range.

a) Pollution by moisture / presence of acidity
Moisture, in contact with the refrigerant and oil, causes the formation of acids.
When we discover the presence of moisture in a refrigeration circuit, with a sight glass such as VCYL, acids are perhaps already present in the circuit.
It is therefore necessary to remove moisture and neutralize acids.
The simple method consists in mounting a « burn-out » filter on the liquid line pipe and on the suction line pipe.

a-1) In the non-reversible installations for commercial refrigeration or air conditioning
The cleaning of the circuit is made by mounting a « burn-out » filter type NCY on the liquid line and a « burn-out » filter type FNCY on the suction line of the compressor.

The « burn-out » filters are equipped with SCHRAEDER® valves which allow to check their saturation by measuring the pressure drop.

After one week of operation, maximum, the following controls must be made:

  • Control of the presence of moisture via a sight glass type VCYL(S).
  • Control of the presence of acidity via an acidity test like TESTOIL-MAS or TESTOIL-POE, made with a sample of oil taken from the compressor crankcase.

If checking still shows the presence of moisture, acidity or a high pressure drop, it is advisable to reiterate the operation with new filters NCY and FNCY.

Once the cleaning procedure is finished, the « burn-out » filters FNCY and NCY will be replaced respectively by permanent filters type FACY on the suction line and DCY on the liquid line.

Note: Filters NCY and FNCY are fully interchangeable with filters DCY and FACY.

Caution: The « BURN-OUT » filters are made for a temporary use only. Do not leave them more than a week on the installation.

a-2) In the installations of higher capacity (supermarket refrigeration, industrial refrigeration, A/C)
The procedure to be followed is similar to the one described in paragraph a-1
CARLY products to use are the cores CCY 48 N (CCY 42 N, CCY 100N).

These cores are inserted in the filter shells mounted on the liquid line and the suction line.

In the same way, acidity has to be checked with an acidity test TESTOIL-MAS or TESTOIL-POE and the moisture must be controlled with a sight glass such as VCYL(S).

Once the cleaning procedure is finished, the cores CCY 48N (CCY 42N, CCY 100N) will be replaced by cores CCY 48 HP (CCY 42 HP, CCY 100 HP, PLATINIUM 48) on the liquid line and by cores CCY 48 I (CCY 42 I, CCY 100 I) on the suction line.

a-3) In the reversible air conditioning installations or heat pumps
The problem is a bit different because the refrigerant can circulate in both directions.
The intervention on the refrigerating circuit is usually done outside the condensing unit, for warranty reasons and simplicity of the intervention.
The cleaning of the refrigerating circuit can be done with the installation of a bi-flow “burn-out” filter like DDNCY, mounted on the liquid and suction line (Φ ≤ 5/8).
When the diameter of the suction pipe is bigger than 5/8 (16 mm), we will have to mount a FNCY filter (one direction flow) on the suction line and lock the air-conditioning unit (or heat pump) in an operation mode (hot or cold).

The installation of a bi-flow cleaning filter drier DDNCY enables to treat at the same time the fluid and oil, while keeping the refrigerant in the circuit..

The control procedure is similar to the one described in paragraph a-1 and a-2.
Once the cleaning is finished, the « BURN-OUT » filters FNCY and DDNCY will be replaced respectively by permanent filters such as FACY on the suction line and DDCY on the liquid line.

During a periodic control of the acidity of a compressor oil, if the oil is acid, draining and replacement of the oil is not sufficient.
The oil is in direct contact with the refrigerant. When the oil is acid, then the refrigerant is too.
The total neutralization of the acidity requires the replacement of the oil and the treatment of the refrigerant with “BURN-OUT” filters or cores.

b) Replacement of a compressor
A compressor breakdown, due to mechanical or electrical reasons, creates particles and a pollution of the circuit.
After replacement of the faulty compressor, it is necessary to mount “BURN-OUT” filters on the liquid line and suction line, to catch the particles and neutralize the eventual acidity of the refrigerant, by following the procedure described in paragraph a).

c) Change of the refrigerant (R22 for example)
The change of a refrigerant by a substitution fluid often requires the change of the oil.
When a mineral or alkyl benzene oil is replaced by a polyol ester oil, it is necessary to empty many times the oil in order to limit the proportion of the mineral/alkyl benzene contained in the polyol ester oil.
The polyol ester oil is very detergent, and when it circulates in the pipings, it causes the unsticking of all impurities which will be found in suspension in the refrigerant
To minimize the risks of pollution in the circuit, it is necessary to mount « BURN-OUT » filters on the suction line and on the liquid line. Doing this, all the particles in the refrigerant and the polyol ester oil, will be trapped.
The combination, of the cleaning of the refrigerating circuit and the oil changes, allows to garantee the good operating of the installation after the refrigerant change.


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