Page 77
XP17
ADDING OR REMOVING REFRIGERANT
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.
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (
D
T)
process using the
illustration in figure 48.
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
1.08 x Temperature rise (F)
Cº
T
Drop
–
D
T
=
ºF
ACTION
53º
19
–
15
=
4
Increase the airflow
58º
14
–
15
=
-1
(3º range) no change
62º
10
–
15
=
-5
Decrease the airflow
D
T
80
24 24 24 23 23 22 22 22 20 19 18 17 16 15
78
23 23 23 22 22 21 21 20 19 18 17 16 15 14
76
22 22 22 21 21 20 19 19 18 17 16 15 14 13
74
21 21 21 20 19 19 18 17 16 16 15 14 13 12
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
57 58 59 60 61 62 63 64 65 66 67 68 69 70
Temperature of air
entering indoor
coil ºF
INDOOR COIL
DRY BULB
DRY
BULB
WET BULB
B
T
Drop
19º
A
Dry-bulb
Wet-bulb ºF
A
72º
B
64º
C
53º
air flow
air flow
All temperatures are expressed in ºF
1.
Determine the desired
D
T
— Measure entering air temperature using dry bulb (
A
) and wet bulb (
B
).
D
T
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
Drop
) =
A
minus
C
.
3.
Determine if fan needs adjustment
— If the difference between the measured
T
Drop
and the desired
D
T
(T
Drop
–
D
T)
is 3º, no adjustment is needed. See example below:
4.
Adjust the fan speed
— See indoor unit instructions to increase/decrease fan speed.
Assume
D
T
= 15 and
A
temp. = 72º, these
C
temperatures would necessitate stated actions:
AIRFLOW
Use the following procedure to adjust for optimal air flow across the indoor coil:
INDOOR COIL
Changing air flow affects all temperatures; recheck
temperatures to confirm that the temperature drop
and
D
T are 3º.
Figure 48. Checking Indoor Airflow over Evaporator Coil using Delta-T Chart
Summary of Contents for iComfort SL18XC1 Series
Page 44: ...Page 44 XP17 Figure 21 Typical XP17 Wiring XP17 XX 230 06...
Page 45: ...Page 45 XP17 Factory Wiring Diagrams Figure 22 Typical Factory Wiring XP17 XX 230 01...
Page 46: ...Page 46 XP17 Figure 23 Typical Factory Wiring XP17 XX 230 02...
Page 47: ...Page 47 XP17 Figure 24 Typical Factory Wiring XP17 XX 230 03 and 05...
Page 48: ...Page 48 XP17 Figure 25 Typical Factory Wiring XP17 XX 230 06...
