RACA Journal June 2023 | Page 42

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charging hoses , closing the manifold gauges and sealing the process tube . Do not remove the label ( showing refrigerant type ) from the cabinet . If it has already been removed or is difficult to read , replace it .

5 . Sealing the process tube To remove the necessity of brazing on the process you can leave the shroeder valve fitted to the system prior to charging but one can braze the process tube closed . The charging connection can be brazed , but care must be taken . It is not possible to ignite the HC refrigerant in the system because it has no air mixed with it . Ventilate the area before you light your brazing torch and while you braze . This will ensure any HC refrigerant that has leaked into the air has been safely dispersed .

To seal the process tube by brazing :

• Pinch the process tube using pinching pliers or a pinch off tool

• Leave the pinching pliers or tool in place and use an electronic leak detector or soapy water to check for leaks at the end of the tube

• Braze the connection

• Remove the pinching pliers or tool and test for leaks again .

“ It is not possible to ignite the HC refrigerant in the system because it has no air mixed with it . Ventilate the area before you light your brazing torch and while you braze .”

Strengthen the area where the pipe has been pinched to prevent bending and later possible leakage at this point

• Check the process tube for leaks as described

6 . Leak testing of process tube When the system has been charged and sealed , the process tube and the entire system should be checked for leaks as described above . Do not check the low side of an R600a system while it is running , the pressures are too low for accurate testing . If a leak is found the refrigerant should be safely removed and the system evacuated as described earlier before the leak is repaired .

Margaret , thank you for your question on HC domestic systems utilising R600a . Remember that only SAQCC gas authorised refrigeration practitioners may work with refrigerants . Let us understand hydrocarbons , they are the future . Thanks to everybody for the overwhelming response . Looking forward to hearing from you .

Grant Laidlaw

Thank you for all for your interesting questions . Send your problems ( and sometimes your creative solutions ) to acra @ netactive . co . za with ‘ Solutions Page ’ in the subject line . You may include pictures . RACA

RACA Journal I June 2023 www . refrigerationandaircon . co . za