Feature
failures due to ‘ overpressure ’ damage to the internals of the gauge which is caused by using a gauge that is not rated for the pressure it is used for .
An easy example , using a R22 set , to try and read R410a , the pressure of the R410a system is about double the operating pressure of the R22 , thus , the gauge is then subjected to “ overpressure ” which damages the bourdon tube inside the gauge , essentially reducing the gauge to scrap , as these internals cannot be repaired .
Never use a manifold set , while nitrogen is being used on the system , many injuries occur , when nitrogen is used on systems without regulators and then just ‘ pops ’ the manifold , as a result .
Incidents have occurred where the manifold ‘ sight glass ’ blew out , due to the nitrogen pressure , and was embedded in the eyes of the technician . This is a serious injury result and can cause blindness . All technicians are advised to avoid this action .
THE TONG TESTER This is a crucial tool , as this allows you to measure the running load amperes while the compressor operates , and in turn , using this information and cross referencing this with the manufacturer ’ s indicated load amperes on the same operating conditions .
You can quickly ascertain the current operating conditions of the system . By checking the amperes , you can identify if the system has a gas charge issue , over or undercharge , and whether your system has a blockage or refrigerant flow issues , superheat setting on the TXV perhaps .
Generally , most technicians know how to safely use a tong tester , however , failures are common , due to the following issues :
• Not checking that the voltage setting is correct , ( trying to measure AC on DC voltage setting )
• Measuring AC amperes , but the tester is on DC amperes
• Ensure that the tester is rated to read the amperes that you are testing for . Many technicians try to read the amperes , but if the tester is not rated for high amperage , it damages the tester , and this results in blown pc boards and burnt terminals on testers and usually results in a new tester being required . These tools are rarely sent in for repair on the electronics of the tester .
VACUUM PUMPS For a system to operate as efficient as possible , you need a system with no moisture or air , thus a ‘ dry ’ system , and no other contaminants to be present when the system is commissioned .
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RACA Journal I April 2021 www . hvacronline . co . za