Daikin RoofPak RPS Series Installation And Maintenance Manual page 98

Economizer Start-Up
Adjust dampers properly. Improper adjustment can damage
the dampers.
When an economizer is ordered without an actuator, the
linkage requires a 3.14" linear stroke to open it fully. Do not
allow dampers to be driven beyond their normal full closed or
full open position.
1. Check whether the outdoor air is suitable for free cooling
by displaying the keypad menu Temperature\OA Damper\
OA Ambient=. "Low" indicates low outdoor air enthalpy;
"High" indicates high outdoor air enthalpy. See
Actuators on page 82
changeover control is working properly. You may want to
take temperature and humidity measurements.
2. At the keypad, set the cooling setpoint low enough so the
controller calls for cooling. Adjust the value in Temperature\
Zone Cooling\Occ Clg Spt= below the temperature shown in
Temperature\Zone Cooling\Control Temp=. In addition, on DAC
units, adjust the value in Temperature\Discharge Cooling\
DAT Clg Spt= below the temperature shown in Temperature\
Discharge Cooling\Disch Air=.
3. Place the unit into cooling mode through the keypad
menu System Summary\System\Ctrl Mode= Cool Only.
4. Observe the outdoor air dampers:
a. If the outdoor enthalpy is low, the control algorithm
should start to modulate the dampers open to
maintain the discharge air setpoint.
b. If the outdoor enthalpy is high, the dampers should
maintain their minimum position. Look at menu
Temperature\OA Damper\MinOA Pos=. Change this
entry to another value. Verify that the dampers
move to the new minimum position setpoint.
5. If the unit is equipped with the electromechanical
enthalpy changeover control (Honeywell H205) and the
outdoor air condition is borderline, attempt to change
its input to the MicroTech III controller by turning the
switch adjustment to "A" or "D." Check enthalpy status
in keypad menu Temperature \ OA Damper \ OA Ambient=.
If this reading is "Low," go to step 5a. If it is "High," go to
step 5b.
NOTE: It may not be possible to check the economizer
operation in both low and high enthalpy states on the
same day. If this is the case, repeat this procedure on
another day when the opposite outdoor air enthalpy
conditions exist.
IM 926-3 • ROOFPAK APPLIED SYSTEMS
CAUTION
Control
to verify that the enthalpy
Check, Test, and Start Procedures
Compressor Startup
Low ambient temperature hazard. Can cause compressor
damage.
Do not attempt to start up and check out the refrigeration
system when the outdoor air temperature is below 50°F unless
the unit is specially equipped for low ambient operation.
With the supply and return fans operational, prepare for
compressor operation.
The unit is shipped with refrigeration service valves closed.
Backseat (open) the discharge and liquid line valves. Connect
service gauges and crack the valves off the backseat
position (one turn forward). Verify that the unit has not lost its
refrigerant charge.
Verify that the crankcase heaters are operating. These should
operate for at least 24 hours before starting the compressors.
Verify that the condenser fan blades are positioned properly
and that the screws are tight (see
must be correctly positioned within its orifice for proper airflow
across the condenser coils.
Figure 114: Condenser Fan Blade Positioning
1.21"
98
CAUTION
Figure 114). The fan blade
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