Lennox Elite Series Installation Instructions Manual page 18

have consulted with the power company and the
voltage condition has been corrected.
6, Set the thermostat for a cooling demand. Turn on
power to the indoor indoor unit and close the outdoor
unit disconnect switch to start the unit.
7. Recheck voltage while the unit is running. Power must
be within range shown on the nameplate,
8, Check system for sufficient refrigerate by using the
procedures listed under Testing and Charging
System,
TESTING AND CHARGING SYSTEM
This system uses HFC-410A refrigerant which operates at
much higher pressures than HCFC-22. The pre-installed
liquid line filter drier is approved for use with HFC-410A
only. Do not replace it with components designed for use
with HCFC-22, This unit is NOT approved for use with coils
which use capillary tubes as a refrigerant metering device.
SETTING UP TO CHECK CHARGE
1. Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HFC-410A,
2, Connect the manifold gauge set to the unit's service
ports as illustrated in figure 2.
• low pressure gauge to vapor service port
• high pressure gauge to liquid service port
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (DT) process using the
illustration in figure 32,
HEATING MODE INDOOR AIRFLOW CHECK
Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:
• Temperature rise between the return air and supply air
temperatures at the indoor coil blower unit,
• Measuring voltage supplied to the unit,
• Measuring amperage being drawn by the heat unit(s).
Then, apply the measurements taken in following formula
to determine CFM:
CFM =
Amps x Volts x 3.41
1.98 x Temperature rise (F)
CALCULATING CHARGE
If the system is void of refrigerant, first, locate and repair
any leaks and then weigh in the refrigerant charge into the
unit, To calculate the total refrigerant charge:
Additional charge
Amount Adjust amount, for specified per
specified variation in line set indoor unit
on length listed on table match-up listed in Total
nameplate in figure 33. tables 4 through 7. charge
+ + =
Temp. }
DT
ofair 180 24 24 24 23 23 22 22 22 20 19 18 17 16 15
entering.._178 23 23 23 22 22 21 21 20 19 18 17 16 15 14
indoor _ I _
coilOF _l.u 22 22 22 21 21 20 19 19 18 17 16 15 14 13
I _'174 21 21 21 20 19 19 18 17 16 16 15 14 13 12
_[72 20 20 19 18 17 17 16,/_15 14 13 12 11 10
70 19 19 18 18 17 17 16 15 15 14 13 12 11 10
Wet-bulb°F 57 58 59 60 61 62 63 64 65 66 67 68 69 70 [
n
90
DRY
BULB
All temperatures are iNDOOR WET
expressed in °F COiL BULB
Step 1. Determine the desired DT--Measure entering air tempera-
ture using dry bulb (A) and wet bulb (B). DT is the intersecting value of
A and B in the table (see triangle).
Step 2. Find temperature drop across coil--Measure the coil's dry
bulb entering and leaving air temperatures (A and C). Temperature
Drop Formula: (TDrop) = A minus C.
Step 3. Determine if fan needs adjustment--If the difference be-
tween the measured TDrop and the desired DT (TDropiDT) is within
±3 °, no adjustment is needed, See examples: Assume DT = 15 and A
temp. = 72 °, these C temperatures would necessitate stated actions:
C °
TDrop-
DT = °F ACTION
53° 19 - 15 = 4 Increase the airflow
58° 14 - 15 = -1 (within +3° range) nochange
62 ° 10 - 15 = -5 Decrease the airflow
Step 4. Adjust the fan speed--See indoor unit instructions to in-
crease/decrease fan speed.
Changing air flow affects all temperatures; recheck temperatures to
confirm that the temperature drop and DT are within +3 °.
Figure 32. Checking Indoor Airflow over Evaporator Coil using Delta-T Chart
WEIGH
Refrigerant Charge per Line Set Length
Liquid Line Ounces per 5 feet (g per 1.5 m)
Set Diameter adjust from 15 feet (4.6 m) line set*
3/8" (9.5 mm) 3 ounce per 5' (85 g per 1.5 m)
NOTE - *If line length is greater than 15 ft. (4.6 m), add this
amount. If line length is less than !5 ft. (4.6 m), subtract this
amount.
LENNOX
_i|m[IWiIiiiHi
1. Check Liquid and suction line pressures
2. Compare unit pressures with tables 8 and
9, Normal Operating Pressures.
3. Conduct leak check; evacuate as
previously outlined,
4. Weigh in the unit nameplate charge plus
any charge required for line set differences
over feet,
This nameplate is for illustration purposes
only. Go to actual nameplate on outdoor
unit for charge information.
Figure 33. Using Weigh In Method
505329M 04/08
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