25
The custom settings of the CO
2
sensor can be changed any-
time after the sensor is energized. Follow the steps below to
change the non-standard settings:
1. Press Clear and Mode buttons. Hold at least 5 seconds
until the sensor enters the Edit mode.
2. Press Mode twice. The STDSET Menu will appear.
3. Use the Up/Down button to toggle to the NONSTD menu
and press Enter.
4. Use the Up/Down button to toggle through each of the
nine variables, starting with Altitude, until the desired set-
ting is reached.
5. Press Mode to move through the variables.
6. Press Enter to lock in the selection, then press Mode to
continue to the next variable.
Dehumidification of Fresh Air with DCV Control
— Infor-
mation from ASHRAE indicates that the largest humidity load
on any zone is the fresh air introduced. For some applications,
a device such as a 62AQ energy recovery unit is added to re-
duce the moisture content of the fresh air being brought into the
building when the enthalpy is high. In most cases, the normal
heating and cooling processes are more than adequate to re-
move the humidity loads for most commercial applications.
If normal rooftop heating and cooling operation is not ade-
quate for the outdoor humidity level, an energy recovery unit
and/or a dehumidification option should be considered.
Step 7 — Adjust Evaporator-Fan Speed — Ad-
just evaporator-fan rpm to meet jobsite conditions.
For units with electric heat, required minimum cfm is 2250
for 50HJ008,009 and 3000 for 50HJ012 and 014. See Table 9
for exceptions.
Table 9 — Minimum Required
Airflow Exceptions
Tables 10 and 11 show fan rpm at motor pulley settings or
standard and high-static motors. Tables 12 and 13 show
evaporator-fan motor data. See Tables 14 and 15 and Fig. 43
for accessory and option static pressure drops. Refer to
Tables 16-29 to determine fan speed settings.
Fan motor pulleys are factory set for speed shown in
Table 1.
To change fan speeds:
1. Shut off unit power supply and install lockout tag.
2. Loosen belt by loosening fan motor mounting nuts. See
Fig. 44 and 45.
3. Loosen movable pulley flange setscrew (see Fig. 46).
4. Screw movable flange toward fixed flange to increase
rpm or away from fixed flange to decrease rpm. Increas-
ing fan rpm increases load on motor. Do not exceed max-
imum speed specified in Table 1.
5. Set movable flange at nearest keyway of pulley hub and
tighten setscrew. (See Table 1 for speed change for each
full turn of pulley flange.)
Table 8 — CO
2
Sensor Standard Settings
LEGEND
ppm — Parts Per Million
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
SETTING EQUIPMENT OUTPUT
VENTILATION
RATE
(cfm/Person)
ANALOG
OUTPUT
CO
2
CONTROL RANGE
(ppm)
OPTIONAL
RELAY SETPOINT
(ppm)
RELAY
HYSTERESIS
(ppm)
1
Interface w/Standard
Building Control System
Proportional Any
0-10V
4-20 mA
0-2000 1000 50
2 Proportional Any
2-10V
7-20 mA
0-2000 1000 50
3 Exponential Any
0-10V
4-20 mA
0-2000 1100 50
4
Economizer
Proportional 15
0-10V
4-20 mA
0-1100 1100 50
5 Proportional 20
0-10V
4-20 mA
0- 900 900 50
6 Exponential 15
0-10V
4-20 mA
0-1100 1100 50
7 Exponential 20
0-10V
4-20 mA
0- 900 900 50
8 Health & Safety Proportional —
0-10V
4-20 mA
0-9999 5000 500
9
Parking/Air Intakes/
Loading Docks
Proportional —
0-10V
4-20 mA
0-2000 700 50
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