Setup For Checking And Adding Charge - Lennox 14HPX?018 Installation Instructions Manual

Temp.
80 24 24 24 23 23 22 22 22 20 19 18 17 16 15
of air
entering
78 23 23 23 22 22 21 21 20 19 18 17 16 15 14
indoor
76 22 22 22 21 21 20 19 19 18 17 16 15 14 13
coil ºF
74 21 21 21 20 19 19 18 17 16 16 15 14 13 12
A 72 20 20 19 18 17 17 16 15 15 14 13 12 11 10
70 19 19 18 18 17 17 16 15 15 14 13 12 11 10
Wet−bulb ºF
57 58 59 60 61 62 63 64 65 66 67 68 69 70
T
Drop
C
19º
53º
air flow
DRY
BULB
All temperatures are
expressed in ºF
Figure 15. Checking Indoor Airflow over Evaporator Coil using Delta−T (DT) Chart
CHECK
EXPANSION VALVE
LOW HUGH
PRESSURE PRESSURE
GAUGE MANIFOLD
TO
HFC−410
A DRUM
NOTE − USE GAUGE PORTS ON VAPOR LINE VALVE AND LIQUID VALVE FOR EVACUATING REFRIGERANT
LINES AND INDOOR COIL. USE VAPOR GAUGE PORT TO MEASURE VAPOR PRESSURE DURING CHARGING.
Figure 16. 14HPX Cooling Cycle (Showing Gauge Manifold Connections)
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta−T (
HEATING MODE INDOOR AIRFLOW CHECK
Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:
S
temperature rise between the return air and supply air
temperatures at the indoor coil blower unit,
S
measuring voltage supplied to the unit,
S
measuring amperage being drawn by the heat unit(s).
Then, apply the measurements taken in following formula
to determine CFM:
Amps x Volts x 3.41
CFM =
1.08 x Temperature rise (F)
DT
B
A
72º
B
air flow
64º
DRY
BULB
INDOOR
WET
BULB
COIL
DISTRIBUTOR
BIFLOW
FILTER /
OUTDOOR
DRIER
COIL
MUFFLER
LIQUID
SERVICE
PORT
LIQUID
LINE
VALVE
COMPRESSOR
DT)
process (figure 15).
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: (T ) = A minus C.
Drop
Step 3. Determine if fan needs adjustment If the difference be-
tween the measured T
+3º, no adjustment is needed. See examples: Assume DT = 15 and A
temp. = 72º, these C temperatures would necessitate stated actions:
DT
Cº T –
Drop
53º 19 – 15
58º 14 – 15
62º 10 – 15
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 +3º.
OUTDOOR UNIT
REVERSING VALVE
VAPOR
SERVICE
PORT
VAPOR
LINE
VALVE
CHECK EXPANSION VALVE

Setup for Checking and Adding Charge

SETUP FOR CHARGING
Connect the manifold gauge set to the unit's service ports
(see figure 16):
S
low pressure gauge to vapor service port
S
high pressure gauge to liquid service port
Close manifold gauge set valves. Connect the center man-
ifold hose to an upright cylinder of HFC−410A.
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:
Amount Adjust amt. for
specified variation in
on line set length
nameplate (table in figure 17)
+
Page 13
and the desired DT (T
Drop Drop
=
ºF ACTION
=
4 Increase the airflow
=
−1 (within +3º range) no change
=
−5 Decrease the airflow
NOTE − ARROWS INDICATE DIRECTION
OF REFRIGERANT FLOW
INDOOR UNIT
Additional charge
specified per
indoor unit matchup
(tables 4 through 10)
+
–DT) is within
INDOOR
COIL
Total
charge
=
14HPX SERIES