Airflow Adjustments - Daikin DBC Series Installation Instructions Manual

The Startup, Adjustments, and Checks procedure provides a step-
by-step sequence which, if followed, will assure the proper startup
of the equipment in the minimum amount of time. Air balancing
of duct system is not considered part of this procedure. However,
it is an important phase of any air conditioning system startup and
should be performed upon completion of the Startup, Adjustments,
and Checks procedure. The Startup, Adjustments, and Checks
procedure at outside ambients below 55°F should be limited to a
readiness check of the refrigeration system with the required final
check and calibration left to be completed when the outside
ambient rises above 55°F.
T H O C
EMPORARY EATING R OOLING
If the unit is to be used for temporary heating or cooling, a "Startup,
Adjustments, and Checks" must first be performed in accordance
with this manual. After the machines are used for temporary
heating or cooling, inspect the coils, fans, and motors for
unacceptable levels of construction dust and dirt and install new
filters.
C R
ONTRACTOR ESPONSIBILITY
The installing contractor must be certain that:
• All supply and return air ductwork is in place, properly
sealed and corresponds with installation instructions.
• All thermostats are mounted and wired in accordance
with installation instructions.
• All electric power, all gas, hot water or steam line
connections, and the condensate drain installation have
been made to each unit on the job. These main supply
lines must be functional and capable of operating all units
simultaneously.
• All filters are in place.
R C I C
OOF URB NSTALLATION HECK
Inspect the roof curb for correct installation. The unit and curb
assembly should be level. Inspect the flashing of the roof mounting
curb to the roof, especially at the corners, for good workmanship.
Also check for leaks around gaskets. Note any deficiencies in a
separate report and forward to the contractor.
O , F C
BSTRUCTIONS AN LEARANCE AND
Remove any extraneous construction and shipping materials that
may be found during this procedure. Rotate all fans manually to
check for proper clearances and that they rotate freely. Check for
bolts and screws that may have jarred loose during shipment to
the job site. Retighten if necessary. Re-tighten all electrical
connections.
F D C
IELD UCT ONNECTIONS
Verify that all duct connections are tight and that there is no air
bypass between supply and return.
F S C
ILTER ECTION HECK
Remove filter section access panels and check that filters are
properly installed. Note airflow arrows on filter frames.
W
IRING
P - P
RE STARTUP RECAUTIONS
It is important to your safety that the unit has been properly
grounded during installation. Check ground lug connection in main
control box for tightness prior to closing circuit breaker or
disconnect switch. Verify that supply voltage on line side of
disconnect agrees with voltage on unit identification plate and is
within the utilization voltage range as indicated in Appendix C
Electrical Data.
System Voltage - That nominal voltage value assigned to a circuit
or system for the purpose of designating its voltage class.
Nameplate Voltage - That voltage assigned to a piece of equipment
for the purpose of designating its voltage class and for the purpose
of defining the minimum and maximum voltage at which the
equipment will operate.
Utilization Voltage - The voltage of the line terminals of the
equipment at which the equipment must give fully satisfactory
performance. Once it is established that supply voltage will be
maintained within the utilization range under all system conditions,
check and calculate if an unbalanced condition exists between
phases. Calculate percent voltage unbalance as follows:
Three Phase Models Only
3) PERCENT VOLTAGE
UNBALANCE
HOW TO USE THE FORMULA:
EXAMPLE: With voltage of 220, 216, and 213
1) Average Voltage = 220+216+213=649 / 3 = 216
2) Maximum Voltage Deviations from Average Voltage = 220 - 216 = 4
3) Percent Voltage Unbalance = 100 x
Percent voltage unbalance MUST NOT exceed 2%

AIRFLOW ADJUSTMENTS

The drive on the supply fan is typically set in the middle of the
RPM range. The drive motor sheave pitch diameter is field
adjustable for the required airflow. Refer to the following "Drive
Adjustments" section.
When the final adjustments are complete, the current draw of the
motor should be checked and compared to the full load current
rating of the motor. The amperage must not exceed the service
factor stamped on the motor nameplate. The total airflow must
not be less than that required for operation of the electric heaters
or the furnace.
If an economizer is installed, check the unit operating balance with
the economizer at full outside air and at minimum outside air. Upon
completion of the air flow balancing, we recommend replacing
the variable pitched motor sheave with a properly-sized fixed
sheave. A matching fixed sheave will provide longer belt and
bearing life and vibration free operation. Initially, it is best to have
a variable pitched motor sheave for the purpose of airflow
balancing, but once the balance has been achieved, fixed sheaves
maintain alignment and minimize vibration more effectively.
11
2) MAXIMUM VOLTAGE DEVIATIONS
FROM AVERAGE VOLTAGE
= 100 X
1) AVERAGE VOLTAGE
4 400
= = 1.8%
216 216
.