GSX14 Service Manual

SERVICING
167
Additional Refrigerant
(oz. per lineal foot)
3/8” liquid only 0.60
3/8” liquid and 5/8” suction 0.63
3/8” liquid and 3/4" suction 0.67
3/8” liquid and 7/8” suction 0.74
3/8” liquid and 1 1/8” suction 0.78
Line set sizes
Table 5-3. Additional Refrigerant Per Foot.
25 50 75 100 125 150 175
3/8" liquid line only
15 30 45 60 75 90 105
3/8" liquid line & 5/8" suction line
16 32 47 63 79 95 110
3/8" liquid line & 3/4" suction line
17 34 50 67 84 101 117
3/8" liquid line & 7/8" suction line
18 35 53 70 88 105 123
3/8" liquid line & 1-1/8" suction line
20 39 59 78 98 117 137
Additional lineal line length over 15 feet
Initial refrigerant addition (oz.)
Table 5-4. Initial Refrigerant for Given Line Length
S-202 DUCT STATIC PRESSURES AND/OR STATIC
PRESSURE DROP ACROSS COILS
This minimum and maximum allowable duct static pressure
for the indoor sections are found in the specifications section.
Tables are also provided for each coil, listing quantity of air
(CFM) versus static pressure drop across the coil.
Too great an external static pressure will result in insufficient
air that can cause icing of the coil. Too much air can cause
poor humidity control and condensate to be pulled off the
evaporator coil causing condensate leakage. Too much air
can also cause motor overloading and in many cases this
constitutes a poorly designed system.
S-203 AIR HANDLER EXTERNAL STATIC
To determine proper air movement, proceed as follows:
1. Using a draft gauge (inclined manometer), measure the
static pressure of the return duct at the inlet of the unit,
(Negative Pressure).
2. Measure the static pressure of the supply duct, (Positive
Pressure).
3. Add the two readings together.