York Predator DM090 Installation Instruction

Also see for PREDATOR DM 090: Installation manual Technical guide Installation manual Installation manual Technical guide

035-17311-000 REV A (1200)28 Unitary Products Group1. Remove the dot plugs from the duct panel (for location ofthe dot plugs see figure 11).2. Insert eight-inches of 1/4 inch metal tubing into the air-flow on both sides of the indoor coil.NOTE:The tubes must be inserted and held in a position per-pendicular to the air flow so that velocity pressure will notaffect the static pressure readings.3. Use an inclined manometer to determine the pressuredrop across a dry evaporator coil. Since the moisture onan evaporator coil can vary greatly, measuring the pres-sure drop across a wet coil under field conditions couldbe inaccurate. To assure a dry coil, the compressorsshould be de-activated while the test is being run.NOTE:De-energize the compressors before taking any testmeasurements to assure a dry evaporator coil.4. The CFM through the unit with clean 2 inch filters can bedetermined from the pressure drop indicated by themanometer by referring to the curves in Figure 21.5. After readings have been obtained, remove the tubesand replace the dot plugs. .SUPPLY AIR DRIVE ADJUSTMENTAt unit start-up, the measured CFM may be higher or lowerthan the required CFM. To achieve the required CFM, thespeed of the drive may have adjusted by changing the datumdiameter (DD) of the variable pitch motor sheave asdescribed below:Use the following table and the DD calculated per the aboveequation to adjust the motor variable pitch sheave.EXAMPLEA 10 ton unit was selected to deliver 4,000 CFM with a 5 HPmotor, but the unit is delivering 3,750 CFM. The variablepitch motor sheave is set at 2 turns open.Use the equation to determine the required DD for the newmotor sheave,Use Table 29 to locate the DD nearest to 4.26 in. Close thesheave to 1/2 turn open.New BHPNew motor AmpsTABLE 28: INDOOR BLOWER SPECIFICATIONSMODEL MOTOR MOTOR SHEAVE BLOWER SHEAVE BELTHP RPM Eff. SF Frame Datum Dia. (in.) Bore (in.) Model Datum Dia. (in.) Bore (in.) ModelDM090 1-1/2 1725 80% 1.15 56 3.4 - 4.4 7/8 1VM50 9.0 1 AK94 A572 1725 80% 1.15 56 3.4 - 4.4 7/8 1VM50 7.5 1 AK79 A55DM120 2 1725 80% 1.15 56 3.4 - 4.4 7/8 1VM50 8.5 1 AK89 A563 1725 80% 1.15 56 3.4 - 4.4 7/8 1VM50 7.0 1 AK74 A54DM150 3 1725 80% 1.15 56 3.4 - 4.4 7/8 1VM50 7.0 1 AK74 A545 1725 87% 1.15 184T 4.3 - 5.3 1 1/8 1VP56 6.7 1 BK77 BX55Failure to properly adjust the total system air quan-tity can result in extensive blower damage.Specified CFMMeasured CFM-------------------------------------   Existing DD• New DD=Before making any blower speed changes reviewthe installation for any installation errors, leaks orundesirable systems effects that can result in lossof airflow.Even small changes in blower speed can result insubstantial changes in static pressure and BHP.BHP and AMP draw of the blower motor willincrease by the cube of the blower speed. Staticpressure will increase by the square of the blowerspeed. Only qualified personnel should makeblower speed changes, strictly adhering to the fanlaws.4,000 CFM3,750 CFM---------------------------   4.0 in.• 4.26 in.=Speed increase( )3 BHP at 3,750 CFM•=Speed increase( )3 Original BHP•=New BHP=Speed increase( )3= Amps at 3,750 CFM•Speed increase( )= 3 Orignial Amps•New Amps=