CHARGING BY SUPERHEAT

CHECK AIR FLOW MAKE SURE FILTERS ARE CLEAN NO RESTRICTIVE FILTERS IN PLACE IS THE BLOWER WHEEL CLEAN IS THE EVAPORATOR COIL CLEAN MAKE SURE YOU HAVE 400 CFM OF AIR FLOW PER TON

FIXED ORFICE SYSTEMS Connect service gauges to base-valve service ports . Be sure to purge the lines. Install thermometer to the suction line and insulate for an accurate reading Refer to the table for proper system Superheat Add charge to lower Superheat Remove charge to raise Superheat Remove gauge lines carefully

SUPERHEAT TABLE

USING SUPERHEAT TABLE GET THE OUTSIDE AMBIENT TEMPERATURE IN THE SHADE OF THE CONDENSING UNIT GET THE RETURN DRY BULB TEMPERATURE AT THE RETURN AIR GRILL INTERSECT THE 2 NUMBERS THAT WILL GIVE YOU THE AMOUNT OF SUPERHEAT YOU NEED

EXAMPLE AMBIENT OUTSIDE TEMPERATURE (IN THE SHADE OF THE CONDENSOR) IS 95 DEGRESS RETURN AIR (DRY BULB) IS 75 DEGREES INTERSECT THE 2 NUMBERS AND YOUR SUPER HEAT WILL BE 5 DEGREES

READING THE SATURATED EVAPORATER TEMPERTURE ON THE LOW SIDE OF YOUR COMPOUND GAUGES ( BLUE ) THE OUTSIDE READING IS YOUR PRESSURE THE INSIDE (R 22) IS YOUR SATURATED EVAPORIZING TEMPERTURE

INSTALL THERMOMETER INSTALL ON THE SUCTION LINE ( LARGER LINE ) INSULATE THE PROBE FOR AN MORE ACCURATE READING

EXAMPLE YOUR LOW SIDE PRESSURE IS 75 PSI DIRECTLY BELOW THAT NUMBER IS THE SATURATED EVAPORIZING TEMPERATURE, WHICH IS 44 DEGREES TAKE YOU SUCTION LINE TEMPERTURE, WHICH IS 65 DEGREE

EXAMPLE SUBTRACT THE 2 NUMBERS AND THAT HOW MUCH SUPEREHEAT YOU HAVE 65 - 44 =21 SUPERHEAT WE ONLY NEEDED 5 DEGREES ADD CHARGE TO LOWER SUPER HEAT REMOVE CHARGE TO RAISE SUPERHEAT

CHARGING BY SUBCOOLING

CHECKING SUBCOOLING Refrigeration 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.

CHECKING SUBCOOLING Attach 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.

CHECKING SUBCOOLING EXAMPLE: Liquid Line Pressure = 260 Corresponding Temp. = 120 degrees Thermometer on Liquid line = 109 degrees To obtain the amount of subcooling subtract 109 degrees from 120 degrees. The difference is 11 degrees subcooling. The normal subcooling range is 9 -13 Degrees subcooling for heat pumps units , 14 to 18 degrees for straight cool Units.

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