Page 21
TSA*H4 SERIES
DO NOT CHARGE UNIT
(Results of charging at low
temperatures not reliable)
START: Measure outdoor ambient temperature
USE WEIGH‐IN METHOD
Weigh‐in or remove refrigerant
based upon line length
SCº (Subcooling) Values (F:+/-1.0° [C: +/-0.6°])
BLOCK OUTDOOR COIL: [sometimes necessary with lower
temperatures] Use cardboard or plastic sheet to restrict the airflow
through the outdoor coil to achieve pressures from 325-375 psig
(2240-2585 kPa).
Higher pressures are needed to check charge.
Block equal sections of air intake panels and move coverings
sideways until the liquid pressure is in the above noted ranges.
If value is
MORE
than shown, remove
refrigerant.
1. Confirm proper airflow across coil using figure
18.
2. Compare unit pressures with Table 3,
Normal
Operating Pressures
.
3. Set thermostat to call for heat (must have a
cooling load between 70‐80ºF (21-26ºC)
4. Connect gauge set
5. Measure outdoor ambient temperature
6. When heat demand is satisfied, set thermostat to
call for cooling
7. Allow temperatures and pressures to stabilize.
NOTE - If necessary, block outdoor coil to
maintain 325 - 375 psig.
8. Record liquid line temperature:
LIQº = ______
9. Measure liquid line pressure and use the value to
determine saturation temperature (see table 4):
SATº = ______
10. Subtract to determine subcooling (SCº):
SATº_____ - LIQº _____ = SCº _____
11. Compare results with table below.
Figure 21. HFC-410A Subcooling TXV Charge
MORE
or
LESS
If value is
LESS
than shown, add
refrigerant.
If refrigerant is added
or removed, verify
charge using the
Approach Method
.
64ºF and
BELOW
65ºF
and
ABOVE
ABOVE or
BELOW
ºF (ºC)*
-036
-048
-060
Any
12 (6.7)
9 (5.0)
7 (3.9)
*Temperature of air entering outdoor coil
Table 3. HFC-410A Normal Operating Pressures (10 and S5 psig)
IMPORTANT
Use this table to perform maintenance checks; it is not a procedure for charging the
system. Minor variations in these pressures may be due to differences in installations.
Significant deviations could mean that the system is not properly charged or that a
problem exists with some component in the system.
TSA*H4
-036
-042
-048
-060
5
F (
5
C)*
Liquid / Suction
Liquid / Suction
Liquid / Suction
Liquid / Suction
Expansion Valve (TXV)
65 (18)
263 / 135
238 /132
235 / 132
241 / 130
70 (21)
281 / 138
262 / 133
254 / 132
260 / 130
75 (24)
302 / 140
280 / 134
276 / 134
280 / 132
80 (27)
325 / 142
301 / 136
298 / 134
299 / 134
85 (29)
349 / 142
327 / 137
323 / 135
321 / 135
90 (32)
375 / 143
353 / 138
350 / 137
344 / 134
95 (35)
404 / 144
377 / 140
377 / 138
371 / 135
100 (38)
433 / 145
404 / 141
406 / 140
400 / 137
105 (41)
462 / 147
435 / 142
430 / 141
428 / 139
110 (43)
494 / 149
465 / 143
464 / 142
458 / 141
115 (45)
527 / 150
499 / 144
495 / 143
484 / 142
