49
SERVICING
The following table shows refrigerant amount for every 5 feet of line.
15 (Factory Charge)
139
139
160
237
20
142
142
163
240
25
145
145
166
243
30
148
148
169
246
35
151
151
172
249
40
154
154
175
252
45
157
157
178
255
50
160
160
181
258
55
163
163
184
261
60
166
166
187
264
65
169
169
190
267
70
172
172
193
270
75
175
175
196
273
80
178
178
199
276
85
181
181
202
279
90
184
184
205
282
95
187
187
208
285
100
190
190
211
288
Unit Tonnage
Actual Line Set
Length (ft.)
2-Ton
3-Ton
4-Ton
5-Ton
Refrigerant (Oz.)
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 indoor 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 Pres-
sure).
3. Add the two readings together.
TOTAL EXTERNAL STATIC
NOTE:
Both readings may be taken simultaneously and read di-
rectly on the manometer if so desired.
4. Consult proper table for quantity of air.
