York Single Package Air Conditioner ZR078N10A2AAA50124A

Verify factory phasing of Predator® units

Is the blower rotating in the correct direction?

Is the compressor rotating in the correct direction?

Is the electrical connection to the unit misphased?

Change the phasing of the Field Line Connection at the factory or field supplied disconnect to obtain proper rotation

Is the scroll compressor drawing low amperage?

Close main manual shut-off valve

Open the union fitting upstream of the unit gas valve

Remove screws holding the manifold to the supports

Disconnect wiring to the gas valve

Remove the manifold & gas valve assembly

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

Remove cover screws covering HI and LO pressure adjustment screws

Set thermostat to call for second stage heat and start furnace

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

Gas Connection and Pressure Check

Open the main shut-off valve to admit normal gas pressure to the mains.

Check all joints for leaks using a soap solution or other suitable material.

Check that all filters are in place

Replace filters if cleaning is not possible

Ensure filters are installed ahead of evaporator coil

Verify filters are of the correct size and type