York Single Package Air Conditioner ZR120N20A2AAA50124A

Loosen six nuts (top and bottom) A

Ensure nuts (C) are not loosened

Use belt tension checker to apply a perpendicular force to one belt at the midpoint of the span

Enter the deflection distance obtained (in mm)

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

Tension new belts at the max. deflection force recommended for the belt section

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

Clean all piping of dirt and scale by hammering on the outside of the pipe.

Blow out loose particles from the piping.

Have all gas lines external to the unit been purged of air?

Adjust blower speed to specific static and CFM requirements

Adjust belt tension as required

Tighten blower pulley set screws

Tighten motor sheave set screws

Have the set screws been re-checked after 10-12 hours of run time?

Connect a manometer to the outlet pressure port on the gas valve

Remove cover screws covering HI and LO pressure adjustment screws

Set thermostat to call for second stage heat and start furnace

Record the manifold pressure for second stage (100% input)

Check that all filters are in place

Clean the filters if they are dirty

Replace filters if cleaning is not possible

Install filters ahead of evaporator coil

Ensure filters are of the same size and type as required