York ECO2 YPAL 050 - Manual (Page 49)

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3
JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
17. Verify Variable Frequency Drive setpoints for VAV
unit Supply Fan and optional Variable Frequency
Drive Exhaust and/or Return Fan drives. The Sup-
ply Fan VFD is located to the right of the electrical
control box in the supply fan blower compartment.
Refer to separate manual for VFD operation sup-
plied with the unit.
18. If equipped, open suction line ball valve, discharge
line ball valve, and liquid line ball valve for each
refrigerant system.
UNIT CHECKS – POWER APPLIED
1. Apply 3-phase power and verify its value. Volt-
age im bal ance should be no more than 2% of the
av er age volt age.
2. Verify programmed units Setpoints (refer to “Quick
Start-Up Guide”, Form 100.50-SU3).
3. Verify correct fan rotation – fan should rotate in
direction of arrow on fan housing.
4. Insure proper com pres sor ro ta tion - see following
in struc tion on Ver i fy ing Compressor Ro ta tion.
Verifying Com pres sor Rotation
This unit uses scroll compressors,
which will only operate in one di-
rec tion. Fail ure to observe these steps
could lead to com pres sor failure.
The eco 2 rooftop unit uses hermetic scroll com pres sors,
which only pump in one di rec tion. There fore, it is
nec es sary to verify proper ro ta tion at unit start-up.
Op er a tion of the com pres sor in the reverse di rec tion
will not pump, and cause the com pres sor to cycle on
in ter nal over load. Op er at ing the com pres sor in re verse
for “ex tend ed” pe ri ods can result in fail ure of the
com pres sor.
To verify proper rotation, monitor the suc tion and
dis charge pressures of the re spec tive refrigerant
circuit when the com pres sor cycles on. If the discharge
pres sure increases and suction pressure decreases as the
compressor cycles on, the compressor is properly phased
and operating in the correct rotation.
Compressor Oil Level Check
The oil level can only be tested when the com pres sor is
running in stabilized con di tions, to ensure that there is
no liquid refrigerant in the lower shell of the com pres sor.
When the compressor is run ning in stabilized con di tions,
the oil level must be be tween 1/2 and 3/4 in the oil sight
glass. Note: at shut down, the oil level can fall to the
bot tom limit of the oil sight glass.