Daikin DDC Series Installation And Maintenance Manual

Contents

Daikin DDC Series Installation And Maintenance Manual Manual pdf 12 page image

10T EMPORARY H EATING O R C OOLINGIf the unit is to be used for temporary heating or cooling, a “Startup,Adjustments, and Checks” must first be performed in accordancewith this manual. Failure to comply with this requirement will voidthe warranty. After the machines are used for temporary heatingor cooling, inspect the coils, fans, and motors for unacceptablelevels of construction dust and dirt and install new filters.CONTRACTOR R ESPONSIBILITYThe installing contractor must be certain that:• All supply and return air ductwork is in place, properlysealed and corresponds with installation instructions.• All thermostats are mounted and wired in accordancewith installation instructions.• All electric power, all gas, hot water or steam lineconnections, and the condensate drain installation havebeen made to each unit on the job. These main supplylines must be functional and capable of operating all unitssimultaneously.• All filters are in place.R OOF C URB INSTALLATION C HECKInspect the roof curb for correct installation. The unit and curbassembly should be level. Inspect the flashing of the roof mount-ing curb to the roof, especially at the corners, for good workman-ship. Also check for leaks around gaskets. Note any deficiencies ina separate report and forward to the contractor.O BSTRUCTIONS, FAN C LEARANCE AND W IRINGRemove any extraneous construction and shipping materials thatmay be found during this procedure. Rotate all fans manually tocheck for proper clearances and that they rotate freely. Check forbolts and screws that may have jarred loose during shipment tothe job site. Retighten if necessary. Re-tighten all electrical con-nections.FIELD D UCT C ONNECTIONSVerify that all duct connections are tight and that there is no airbypass between supply and return.FILTER SECTION C HECKRemove filter section access panels and check that filters are prop-erly installed. Note airflow arrows on filter frames.P RE-STARTUP P RECAUTIONSIt is important to your safety that the unit has been properlygrounded during installation. Check ground lug connection in maincontrol box for tightness prior to closing circuit breaker or discon-nect switch. Verify that supply voltage on line side of disconnectagrees with voltage on unit identification plate and is within theutilization voltage range as indicated in Appendix C Electrical Data.System Voltage - That nominal voltage value assigned to a circuitor system for the purpose of designating its voltage class.Nameplate Voltage - That voltage assigned to a piece of equip-ment for the purpose of designating its voltage class and for thepurpose of defining the minimum and maximum voltage at whichthe equipment will operate.Utilization Voltage - The voltage of the line terminals of the equip-ment at which the equipment must give fully satisfactory perfor-mance. Once it is established that supply voltage will be main-tained within the utilization range under all system conditions,check and calculate if an unbalanced condition exists betweenphases. Calculate percent voltage unbalance as follows:Three Phase Models Only3) PERCENT VOLTAGEUNBALANCE2) MAXIMUM VOLTAGE DEVIATIONSFROM AVERAGE VOLTAGE1) AVERAGE VOLTAGEHOW TO USE THE FORMULA:EXAMPLE: With voltage of 220, 216, and 2131) Average Voltage = 220+216+213=649 / 3 = 2162) Maximum Voltage Deviations from Average Voltage = 220 - 216 = 43) Percent Voltage Unbalance = 100 x = = 1.8%Percent voltage unbalance MUST NOT exceed 2% .4216400216= 100 XAIRFLOW ADJUSTMENTSNOTE: For 2 Speed Models, airflow adjustments must be made onhigh speed, i.e., 2nd stage cooling or in heat mode.The drive on the supply fan is typically set in the middle of theRPM range. The drive motor sheave pitch diameter is field adjust-able for the required airflow. Refer to the following “DriveAdjustments” section.When the final adjustments are complete, the current draw of themotor should be checked and compared to the full load currentrating of the motor. The amperage must not exceed the servicefactor stamped on the motor nameplate. The total airflow mustnot be less than that required for operation of the electric heatersor the furnace.If an economizer is installed, check the unit operating balance withthe economizer at full outside air and at minimum outside air. Uponcompletion of the air flow balancing, we recommend replacingthe variable pitched motor sheave with a properly-sized fixedsheave. A matching fixed sheave will provide longer belt and bear-ing life and vibration free operation. Initially, it is best to have avariable pitched motor sheave for the purpose of airflow balanc-ing, but once the balance has been achieved, fixed sheaves main-tain alignment and minimize vibration more effectively. For directdrive units, move green wire for fan.NOTE: On “non-two speed models” (two-speed models have a “V”in the eleventh character of the model number), never run CFMbelow 300 CFM per ton. Evaporator freezing or poor unit perfor-mance is possible.SET EVAPORATOR FAN RPMActual RPM’s must be set and verified with a tachometer or strobelight. Refer to Appendices A and B for basic unit fan RPM. Referalso to “Airflow” section of this manual. With disconnect switchopen, disconnect thermostat wires from terminals Y and W. This