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Case Study
15 July 2015

A-Gas Refrig Health Check passes trial with flying colours

The Problem

The trial at the store focused on a ducted air-conditioning system with two cooling zones. The store has two separate systems in different plant rooms – one at each end of the building. The store was a new maintenance contact for Faircloth & Reynolds and the job had its own challenges.

Each system at the store had two circuits, powered by two Copeland reciprocating compressors, linked in parallel. The circuits supplied a split evaporator in an air handling unit, powered by a sizable Fantech unit pumping air into the duct system.

Each circuit has approximately 150Kw capacity and a charge of around 180kg of refrigerant. Records showed that R407C and R22 had been purchased by the store but there was no information to support what gas the system contained or if they had been inadvertently mixed. Before Faircloth & Reynolds could carry out maintenance work, they had to know what gas was running in the system.

The Solution

Faircloth & Reynolds used RHC to analyse the condition of the refrigerant and the oil in the system. A fully equipped pack is supplied to the customer to take the samples, clean new hoses and fittings are also provided to avoid the potential for cross contamination on sampling.

Taking the Samples

At the store the refrigerant sample was easily taken in liquid form from the receiver vessel on each circuit which was equipped with a quarter inch Schrader valve sample point. The cylinder was placed on scales to ensure that the required minimum of 1-2kg of refrigerant was taken. After purging the hose to clear any air, the liquid refrigerant was introduced using the vacuum in the sample cylinder.

Oil samples were more difficult to get and were taken from the separation system where there was a Schrader valve on the oil filter. The same hose was used to take the oil sample as the refrigerant sample.

Once it had been extracted, the oil was fizzy with dissolved refrigerant and had to be left to stand with the lid off for 30 to 40 minutes before being sealed. Overall the sampling process was quick and easy, taking around 15-20 minutes per circuit, including the time to complete the information forms.

The Results

The samples were sent to A-Gas for full analysis. In return a full report on the refrigerant and the oil, together with the steps needed to improve the health of the system, was sent to Faircloth & Reynolds via Airefrig Australia.

The results showed that all four circuits were running on R407C – in the correct composition and not fractionated. It is likely that the system originally ran on R22 but had been retrofitted to R407C.

The refrigerant in all circuits was in good condition, although moisture levels were well above new refrigerant standard (<10ppm), with one circuit analysed at 175ppm.

Three out of four of the circuits failed on particulates, however the moisture and particulates issue can be resolved by changing the filter driers on each circuit – an easy fix. The findings proved the early warning capability of RHC. Without troubleshooting, there is the risk that moisture can react with HFC refrigerants such as R407C to produce hydrofluoric acid which attacks seals, motor windings and discharge valves causing extensive compressor damage.

Analysis identified that the oil was in good condition in all circuits, although a little dirty with elevated silicon levels. Overall, none of the oil samples raised any concern, although it was recommended that changing the oil filter on three of the four circuits to clean the system would be beneficial.

Testimonials

Faircloth & Reynolds Commissioner Beau Beaton said: “Refrig Health Check came with all the necessary equipment to make taking a sample of oil and refrigerant simple, easy and accurate. The report gave us exactly what we were looking for on an old unlabelled system. We were able to determine the type of refrigerant and quality.”

Airefrig Australia sales manager Kieren Brotherton said: “It was great to see how the contractor used this new product on site and how easy it was to take the refrigerant and oil samples. I believe it will be of great support to customers and a very useful tool to incorporate in their annual maintenance programmes.”

Conclusion

This trial was an ideal test for RHC which proved its value as a product to identify contamination before it causes system damage. The feedback from the wholesaler and contractor showed that RHC more than proved its worth.