Lennox TPA036H4N4 Installation Instructions Manual page 23

GAUGE SET
CONNECTIONS FOR TESTING AND CHARGING
INSIDE OUTDOOR UNIT
ADDING OR REMOVING REFRIGERANT
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
TRUE SUCTION PORT
B
CONNECTION
REFRIGERANT TANK
CHARGE IN
LIQUID PHASE
DIGITAL SCALE
D
TEMPERATURE
SENSOR
AClose manifold gauge set valves and connect the center hose to a cylinder of HFC−410A. Set for
liquid phase charging.
BConnect the manifold gauge set's low pressure side to the true suction port.
CConnect the manifold gauge set's high pressure side to the liquid line service port.
DPosition temperature sensor on liquid line near liquid line service port.
Figure 19. Manifold Gauge Set Setup and Connections
DT
B
A
72º
B
air flow
64º
DRY
BULB
INDOOR
WET
BULB
COIL
Figure 20. Checking Indoor Coil Airflow Guide
MANIFOLD GAUGE SET
HIGH
LOW
A
C
TO LIQUID
LINE SERVICE
VALVE
1. Determine the desired DT Measure entering air temperature
using dry bulb (A) and wet bulb (B). DT is the intersecting value of A
and B in the table (see triangle).
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
3. Determine if fan needs adjustment If the difference between
and the desired DT (T
the measured T
Drop
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
4. Adjust the fan speed See indoor unit instructions to increase/
decrease fan speed.
Changing air flow affects all temperatures; recheck temperatures to
confirm that the temperature drop and DT are within +3º.
Page 23
OUTDOOR UNIT
TEMPERATURE SENSOR
(LIQUID LINE)
–DT) is within +3º, no
Drop
=
ºF ACTION
=
4 Increase the airflow
=
−1 (within +3º range) no change
=
−5 Decrease the airflow
LIQUID LINE
SERVICE
PORT
TPA*H4 SERIES