Carrier Puron R-410A, Инструкции по обслуживанию и техническому обслуживанию, Страница: 36 / 84

36
must be evaluated for design conditions. The maximum damp-
er position must be calculated to provide the desired fresh air.
Typically the maximum ventilation rate will be about 5% to
10% more than the typical cfm required per person, using nor-
mal outside air design criteria.
A proportional anticipatory strategy should be taken with the fol-
lowing conditions: a zone with a large area, varied occupancy,
and equipment that cannot exceed the required ventilation rate at
design conditions. Exceeding the required ventilation rate means
the equipment can condition air at a maximum ventilation rate
that is greater than the required ventilation rate for maximum oc-
cupancy. A proportional-anticipatory strategy will cause the
fresh air supplied to increase as the room CO
2
level increases
even though the CO
2
set point has not been reached. By the time
the CO
2
level reaches the set point, the damper will be at maxi-
mum ventilation and should maintain the set point.
In order to have the CO
2
sensor control the economizer damper
in this manner, first determine the damper voltage output for
minimum or base ventilation. Base ventilation is the ventila-
tion required to remove contaminants during unoccupied peri-
ods. The following equation may be used to determine the per-
cent of outside air entering the building for a given damper po-
sition. For best results, there should be at least a 10 degree
difference in outside and return-air temperatures.
T
O
= Outdoor-Air Temperature
OA = Percent of Outdoor Air
T
R
= Return-Air Temperature
RA = Percent of Return Air
T
M
= Mixed-Air Temperature
Once base ventilation has been determined, set the minimum
damper position potentiometer to the correct position.
The same equation can be used to determine the occupied or
maximum ventilation rate to the building. For example, an out-
put of 3.6 volts to the actuator provides a base ventilation rate
of 5% and an output of 6.7 volts provides the maximum venti-
lation rate of 20% (or base plus 15 cfm per person). Use Fig. 56
to determine the maximum setting of the CO
2
sensor. For ex-
ample, an 1100 ppm set point relates to a 15 cfm per person de-
sign. Use the 1100 ppm curve on Fig. 56 to find the point when
the CO
2
sensor output will be 6.7 volts. Line up the point on
thegraph with the left side of the chart to determine that the
range configuration for the CO
2
sensor should be 1800 ppm.
The EconoMi$er IV controller will output the 6.7 volts from
the CO
2
sensor to the actuator when the CO
2
concentration in
the space is at 1100 ppm. The DCV set point may be left at
2 volts since the CO
2
sensor voltage will be ignored by the
EconoMi$er IV controller until it rises above the 3.6 volt set-
ting of the minimum position potentiometer.
Once the fully occupied damper position has been determined,
set the maximum damper demand controlled ventilation poten-
tiometer to this position. Do not set to the maximum position
as this can result in over-ventilation to the space and potential
high humidity levels.
CO
2
Sensor Configuration
The CO
2
sensor has preset standard voltage settings that can be
selected anytime after the sensor is powered up. (See Table 7.)
Use setting 1 or 2 for Carrier equipment. (See Table 7.)
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.
* CRENTDIF004A00 and CRTEMPSN002A00 accessories are used on
many different base units. As such, these kits may contain parts
that will not be needed for installation.
† 33ZCSENCO2 is an accessory CO
2
sensor.
** 33ZCASPCO2 is an accessory aspirator box required for duct-
mounted applications.
†† CRCBDIOX005A00 is an accessory that contains both 33ZCSEN-
CO2 and 33ZCASPCO2 accessories.
3. Use the Up/Down button to select the preset number. (See
Table 7.)
4. Press Enter to lock in the selection.
5. Press Mode to exit and resume normal operation.
The custom settings of the CO
2
sensor can be changed anytime
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 (Demand Con-
trolled Ventilation) Control
If normal rooftop heating and cooling operation is not adequate
for the outdoor humidity level, an energy recovery unit and/or
a dehumidification option should be considered.
ECONOMI$ER IV PREPARATION
This procedure is used to prepare the EconoMi$er IV for trou-
bleshooting. No troubleshooting or testing is done by perform-
ing the following procedure.
NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm resis-
tor, and a 5.6 kilo-ohm resistor which are not supplied with the
EconoMi$er IV.
1. Disconnect power at TR and TR1. All LEDs should be off.
Exhaust fan contacts should be open.
2. Disconnect device at P and P1.
3. Jumper P to P1.
4. Disconnect wires at T and T1. Place 5.6 kilo-ohm resistor
across T and T1.
5. Jumper TR to 1.
6. Jumper TR to N.
(T
O
x
OA
) + (T
R
x
RA
) = T
M
100 100
Table 7 — EconoMi$er IV Sensor Usage
APPLICATION
ECONOMI$ER WITH OUTDOOR AIR
DRY BULB SENSOR
Accessories Required
Outdoor Air Dry Bulb
None. The outdoor-air dry bulb sensor
is factory-installed.
Differential Dry Bulb CRTEMPSN002A00*
Single Enthalpy HH57AC078
Differential Enthalpy HH57AC078 and CRENTDIF004A00*
CO
2
for DCV
Control using a
wall-mounted
CO
2
sensor
33ZCSENCO2
CO
2
for DCV
Control using a
duct-mounted
CO
2
sensor
33ZCSENCO2†
and
33ZCASPCO2**
O
R CRCBDIOX005A00††
IMPORTANT: Be sure to record the positions of all
potentiometers before starting troubleshooting.