Daikin DBC Series, Installation Instructions Manual

11

Pre-Startup Instructions - General 

CAUTION

To prevent property damage or personal injury, 

do not start the unit until all necessary pre-

checks and tests have been performed.

Prior to the beginning of Startup, Adjustments, and Checks 

procedures, the following steps should be completed in the 

building.

WARNING

MOVING MACHINERY HAZARD!

To prevent possible personal injury or death, 

disconnect power to the unit and padlock in the 

“OFF” position before servicing fans.

On new installations, or if a major component has been 

replaced, the operation of the unit must be checked.

Check unit operation as outlined in the following 

instructions. If any sparking, odors, or unusual sounds 

are encountered, shut off electrical power and recheck for 

wiring errors, or obstructions in or near the blower motors. 

Duct covers must be removed before operating unit.

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.

Temporary Heating Or Cooling

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. Damage or 

repairs due to failure to comply with these requirements 

are not covered under the warranty. 

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.

Contractor Responsibility

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.

• 

  Air filters are in place.

Roof Curb Installation Check

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. 

Obstructions, Fan Clearance and Wiring

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. Re-

tighten if necessary. Re-tighten all electrical connections.

Field Duct Connections

Verify that all duct connections are tight and that there is no 

air bypass between supply and return.

Filter Section Check

Remove filter section access panels and check that filters 

are properly installed. Note airflow arrows on filter frames.

Pre-startup Precautions 

It is important for 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 B Electrical Data.

System Voltage - 

The nominal voltage value assigned to a 

circuit or system for the purpose of designating its voltage 

class.

Nameplate Voltage - 

The 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.