York Rooftop Unit ZH150E54B5B5BCA2A1

Ensure power to the smoke detector is turned off

Inspect the smoke detector for any visible damage

Remove the smoke detector cover

Clean the smoke detector using a soft brush or vacuum cleaner

Reattach the smoke detector cover

Restore power to the smoke detector

Review the installation for any errors, leaks, or undesirable system effects.

Ensure only qualified personnel are making blower speed changes.

Enter the existing datum diameter (DD) of the motor sheave.

Calculate the new datum diameter (DD) using the formula: Required CFM / Measured CFM × Existing DD = New DD.

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

Is the unit equipped with power exhaust fans or a return air fan?

Belt Tension Adjustment Procedure

Loosen the four bolts holding the motor base to the channels

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

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

Enter the deflection distance obtained (in inches)

Use a straight edge from sheave to sheave as a reference line to determine the deflection distance from the normal position

Check the belt tension at least two times during the first 24 hours of operation

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

Deactivate compressors before taking measurements

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

Ensure air filters are clean for accurate measurement

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

Adjust Measured CFM to Required CFM using SUPPLY AIR DRIVE ADJUSTMENT