Lennox XPG15 Series, Руководство по установке

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Page 33
XPG15 SERIES
1. Measure outdoor ambient temperature; determine whether to use cooling mode or
heating mode to check charge.
2. Determine whether you will be using cooling or heating mode, and connect gauge set
for the required mode as illustrated in figure 19.
3. Check liquid and vapor line pressures. Compare pressures with either heat or cooling
mode normal operating pressures in table 6, Normal Operating Pressures .
NOTE The reference table is a general guide. Expect minor pressure variations.
Significant differences may mean improper charge or other system problem.
4. Set thermostat for heat/cool demand, depending on mode being used:
USE
COOLING
MODE
USE
HEATING
MODE
60ºF
(15ºC)
SATº
LIQº
–
SCº =
SUBCOOLING
5. Read the liquid line temperature; record in the LIQº space.
6. Read the liquid line pressure; then find its corresponding temperature in the
temperature/ pressure chart listed in table 7 and record it in the SATº space.
7. Subtract LIQº temperature from SATº temperature to determine subcooling; record
it in SCº space.
8. Compare SCº results with table 5, being sure to note any additional charge for line
set and/or match−up.
9. If subcooling value is greater than shown in table 5 for the applicable unit, remove
refrigerant; if less than shown, add refrigerant.
10. If refrigerant is added or removed, repeat steps 4 through 5 to verify charge.
11. Disconnect gauge set and re−install both the liquid and vapor service valve caps.
USING COOLING MODE
When the outdoor ambient temperature is 60°F (15°C) and
above. Target subcooling values in table 5 are based on 70 to 80°F (21−27°C) indoor
return air temperature; if necessary, operate heating to reach that temperature range;
then set thermostat cooling mode setpoint to 68ºF (20ºC). When pressures have
stabilized, continue with Step 5.
USING HEATING MODE
When the outdoor ambient temperature is below 60°F
(15°C). Target subcooling values in table 5 are based on 65−75°F (18−24°C) indoor
return air temperature; if necessary, operate cooling to reach that temperature range;
then set thermostat heating mode setpoint to 77ºF (25ºC). When pressures have
stabilized, continue with Step 5.
TEST AND CHARGING METHOD
NOTE Insulate liquid line when it is routed through areas where the surrounding ambient temperature could
become higher than the temperature of the liquid line or when pressure drop is equal to or greater than 20 psig.
Figure 22. Using HFC−410A Subcooling Method