2CHECK AIR FLOW MAKE SURE FILTERS ARE CLEAN NO RESTRICTIVE FILTERS IN PLACEIS THE BLOWER WHEEL CLEANIS THE EVAPORATOR COIL CLEANMAKE SURE YOU HAVE 400 CFM OF AIR FLOW PER TON
3FIXED ORFICE SYSTEMSConnect service gauges to base-valve service ports .Be sure to purge the lines.Install thermometer to the suction line and insulate for an accurate readingRefer to the table for proper system SuperheatAdd charge to lower SuperheatRemove charge to raise SuperheatRemove gauge lines carefully
5USING SUPERHEAT TABLEGET THE OUTSIDE AMBIENT TEMPERATURE IN THE SHADE OF THE CONDENSING UNITGET THE RETURN DRY BULB TEMPERATURE AT THE RETURN AIR GRILLINTERSECT THE 2 NUMBERSTHAT WILL GIVE YOU THE AMOUNT OF SUPERHEAT YOU NEED
6EXAMPLEAMBIENT OUTSIDE TEMPERATURE (IN THE SHADE OF THE CONDENSOR) IS 95 DEGRESSRETURN AIR (DRY BULB) IS 75 DEGREESINTERSECT THE 2 NUMBERS AND YOUR SUPER HEAT WILL BE 5 DEGREES
7READING THE SATURATED EVAPORATER TEMPERTURE ON THE LOW SIDE OF YOUR COMPOUND GAUGES ( BLUE )THE OUTSIDE READING IS YOUR PRESSURETHE INSIDE (R 22) IS YOUR SATURATED EVAPORIZING TEMPERTURE
15CHECKING SUBCOOLINGRefrigeration liquid is considered subcooled when its temperature is lower than the saturation temperature corresponding to its pressure. The degree of subcooling equals the degrees of temperature decrease below the saturation temperature at the existing pressure.
16CHECKING SUBCOOLINGAttach an accurate thermometer or preferably a thermocouple type temperature tester to the liquid line as it leaves the condensing unit.Install a high side pressure gauge on the high side (liquid) service valve at the front of the unit.Record the gauge pressure and the temperature of the line.Convert the liquid line pressure gauge reading to temperature by finding the gauge reading in the Temperature – Pressure Chart and reading to the left, find the temperature in F column.The difference between the thermometer reading and pressure to the temperature conversion is the amount of subcooling.
17CHECKING SUBCOOLING EXAMPLE: Liquid Line Pressure = 260 Corresponding Temp. = 120 degreesThermometer on Liquid line = 109 degreesTo obtain the amount of subcooling subtract 109 degrees from 120 degrees.The difference is 11 degrees subcooling. The normal subcooling range is 9 -13Degrees subcooling for heat pumps units , 14 to 18 degrees for straight coolUnits.