Oil Charge; Approach Method (Txv Systems) - Lennox HS26 Series Manual

HS26−018
OUTDOOR
Liq.+ Suct.+
TEMP. (_F)
10 psig 5 psig
142 75
65
167 76
75
194 77
85
223 78
95
256 79
105
If the system is completely void of refrigerant, the recom
mended and most accurate method of charging is to weigh
the refrigerant into the unit according to the total amount
shown on the unit nameplate. Also refer to the SPECIFI
CATIONS tables on page 1 for early model HS26 units and
page 2 for late model HS26 units.
If weighing facilities are not available or if unit is just low on
charge, the following procedure applies.
The following procedures are intended as a general guide
for use with expansion valve systems only. For best re
sults, indoor temperature
70 °F and 80 °F. Outdoor temperature should be 60 °F or
above. Slight variations in charging temperature and pres
sure should be expected. Large variations may indicate a
need for further servicing.

APPROACH METHOD (TXV SYSTEMS)

(Ambient Temperature of 60_F [16_C] or Above)
1− Connect gauge manifold. Connect an upright HCFC 22
drum to center port of gauge manifold.
IMPORTANT
The following procedure requires accurate read
ings of ambient (outdoor) temperature, liquid tem
perature and liquid pressure for proper charging.
Use a thermometer with accuracy of +2 °F and a
pressure gauge with accuracy of +5 PSIG.
2− Record outdoor air (ambient) temperature.
3− Operate indoor and outdoor units in cooling mode. Allow
units to run until system pressures stabilize.
TABLE 10 (Late Models)
NORMAL OPERATING PRESSURES
HS26−024 HS26−030
Liq.+ Suct.+ Liq.+
10 psig 5 psig 10 psig
143 76 139
168 77 163
196 78 191
226 79 223
260 80 255
should be between
HS26−036
Suct.+ Liq.+ Suct.+ Liq.+
5 psig 10 psig 5 psig 10 psig
72 138 70
73 164 71
74 192 72
76 223 73
77 256 75
4− Make sure thermometer well is filled with mineral oil be
fore checking liquid line temperature.
5− Place thermometer in well and read liquid line tempera
ture. Liquid line temperature should be a few degrees
warmer than the outdoor air temperature. Tables 11 and
12 show how many degrees warmer the liquid line tem
perature should be.
Add refrigerant to make the liquid line cooler.
Recover refrigerant to make the liquid line warmer.
APPROACH METHOD − EXPANSION VALVES SYSTEM
MODEL
H2−26−261,311
HS26−411
HS26−461
APPROACH METHOD − EXPANSION VALVES SYSTEMS
MODEL
HS26−036, 048
HS26−018, 030, 042, 060
HS26−024
6− When unit is properly charged liquid line pressures
should approximate those in table 9 or table 10.
D−Oil Charge
Refer to Table 1 and 2 on page 6.
Page 13
HS26−042 HS26−048
Suct.+ Liq.+ Suct.+
5 psig 10 psig 5 psig
141 74 130 71
166 75 156 72
186 76 175 73
227 78 216 75
261 79 251 77
TABLE 11
Liquid Line _F (_C) Warmer Than
Outside Ambient Temperature
3 + 1 (1.6 + .5)
4 + 1 (2.2 + .5)
6 + 1 (3.3 + .5)
TABLE 12
Liquid Line _F (_C) Warmer Than
Outside Ambient Temperature
5 + 1 (2.8 + .5)
8 + 1 (4.44 + .5)
9 + 1 (5+ .5)
HS26−060
Liq.+ Suct.+
10 psig 5 psig
171 73
196 74
225 75
232 76
251 77