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Insert the data into the following equations:
T1 (cfm1) + T2 (cfm2)
= T3
cfm3
cfm2 = (cfm3 – cfm1)
Therefore:
T1 (cfm1) + T2 (cfm3 – cfm1)
= T3
cfm3
Use this equation to determine cfm1, which is the
minimum airflow across the economizer.
(T3 – T2) cfm3
cfm1 =
(T1 – T2)
If cfm1 does not match the desired minimum airflow
from Step 1, readjust the minimum position setting
screw.
8. Determine the enthalpy changeover set point from
Fig. 25. The enthalpy changeover set point should be
set to return the outdoor air damper to the minimum po-
sition when enthalpy rises above the set point. The set-
tings are A, B, C, and D. Set the enthalpy changeover
per the setting in Fig. 25.
9. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter ac-
cess panel slides along the tracks and is securely en-
gaged. See Fig. 26.
10. Fasten hood top and side plate assembly (Fig. 27) to
outdoor-air opening panel with screws provided and in-
stall bottom stop.
11. Slide outdoor-air inlet screens into screen track on hood
side plate. While holding screens in place, fasten screen
retainer to hood using screws provided. See Fig. 28.
NOTE: Refer to Fig. 29 for economizer barometric re-
lief damper characteristics.
Step 7 — Adjust Evaporator-Fan Speed —
Ad-
just evaporator-fan speed to meet jobsite conditions.
For units with electric heat, required minimum cfm is 2250
for 50HJ008,009 and 3000 for 50HJ012 and 014 with the
following exceptions:
UNIT
UNIT
VOLTAGE
HEATER
kW
UNIT
CONFIG-
URATION
REQUIRED
MINIMUM
CFM
50HJ012
and 014
208/230
42.4
Horizontal
3200
208/230
50.0
Horizontal
3200
460
50.0
Horizontal
or Vertical
3200
50HJ008-
014
575
17.0
Horizontal
or Vertical
2800
34.0
2350
CONTROL
CURVE
CONTROL POINT
(APPROX. DEG.)
AT 50% RH
A
73 (23)
B
70 (21)
C
67 (19)
D
63 (17)
RH — Relative Humidity
NOTE: Temperatures are in Fahrenheit. Temperatures in parentheses are in
Celsius.
Fig. 25 — Enthalpy Settings for Parablade
Economizer
Fig. 26 — Panels Reinstalled on Unit
Fig. 27 — Outdoor-Air Hood Installed on Unit
Fig. 28 — Filter Installed on Outdoor-Air Hood
16
Содержание 50HJ008-014
Страница 29: ...Fig 33 MoistureMiser Option Operation 29...
Страница 32: ...Fig 39 Cooling Charging Chart Standard 50HJ009 Fig 40 Cooling Charging Charts Standard 50HJ012 32...
Страница 39: ......