York Rooftop Unit ZH090E54R5B5BCA2A1

Ensure the following components are present

Loosen the four bolts holding the motor base to the channels

Adjust the belt by turning nuts 'A' (see detail 'B')

Apply perpendicular force to one belt at the midpoint of the span using a belt tension checker

Enter the deflection distance obtained (in inches)

Use the recommended deflection force per the Belt Adjustment Table

Is the belt tension within the recommended deflection force range?

Inspect the smoke detector for any visible damage or obstruction

Is the smoke detector securely mounted?

Turn off the power to the smoke detector

Remove the smoke detector from its mounting base

Clean the smoke detector using a vacuum cleaner or compressed air

Reattach the smoke detector to its mounting base

Check the electrical supply voltage being supplied

Set the room thermostat to the off position

Set the room thermostat fan switch to on

Check blower drive belt tension

Check the unit supply air (CFM)

Measure evaporator fan motor's amp draw

Remove the dot plugs from the duct panel

Insert eight inches of 1/4 inch metal tubing into the airflow on both sides of the indoor coil

Ensure tubes are perpendicular to the airflow

Determine the pressure drop across a dry evaporator coil using an Inclined Manometer or Magnehelic

Are the compressors de-energized before taking measurements?

Determine the CFM through the unit from the pressure drop indicated by the manometer

Adjust Measured CFM to Required CFM

Review installation for errors, leaks, or undesirable system effects

Ensure only qualified personnel make blower speed changes

Adhere strictly to fan laws during adjustments

Enter existing datum diameter (DD)