SERVICING
57
The following table shows refrigerant amount for every 5 feet of
line.
15 (Factory Charge) 165 272 272 242
20 168 275 275 245
25 171 278 278 248
30 174 281 281 251
35 177 284 284 254
40 180 287 287 257
45 183 290 290 260
50 186 293 293 263
55 189 296 296 266
60 192 299 299 269
65 195 302 302 272
70 198 305 305 275
75 201 308 308 278
80 204 311 311 281
85 207 314 314 284
90 210 317 317 287
95 213 320 320 290
100 216 323 323 293
105 219 326 326 296
110 222 329 329 299
115 225 332 332 302
120 228 335 335 305
125 231 338 338 308
130 234 341 341 311
135 237 344 344 314
140 240 347 347 317
145 243 350 350 320
150 246 353 353 323
155 249 356 356 326
160 252 359 359 329
165 255 362 362 332
170 258 365 365 335
175 261 368 368 338
180 264 371 371 341
185 267 374 374 344
190 270 377 377 347
195 273 380 380 350
200 276 383 383 353
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.
If external static pressure is being measured on a furnace to de-
termine airflow, supply static must be taken between the "A" coil
and the furnace.
TOTAL EXTERNAL STATIC
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