Johnson Controls York VERSECON YSWD 012, Installation Operation & Maintenance

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36
JOHNSON CONTROLS
FORM 145.05-NOM1 (708)
11. Verify the supply fan hold down bolts have been
removed
(refer to Figure 2).
12. Verify the supply fan rotates freely. Verify proper
drive alignment of the supply fan. Refer to the
“ Maintenance ” Section of the manual for proper
procedure.
13. Verify the unit condenser water connections and
condensate drain connections have been piped.
14. Verify the entering and leaving condenser water
temperature sensors are mounted.
15. Verify the return air temperature sensor and op-
tional outdoor temperature sensors have been
installed and that the wiring has been made to the
Unit Control Board. Refer to Unit Wiring Dia-
gram.
16. Verify that all mechanical and electrical inspections
have been completed per local codes.
17. Make sure the trap for the main evaporator drain
pan and the drain pan under the supply blower have
been primed by pouring water in both pans until
water exits the condensate drain line.
18. Read Section 5 of this manual in order to under-
stand the sequence of operation and Section 6
to understand how to navigate through the User
Interface.
UNIT CHECKS – POWER APPLIED
1. Apply 3-phase power to the unit and verify it falls
within the voltage range given in Table 2.
2. Check for voltage imbalance. Voltage imbalance
should not exceed 2% of the average voltage.
3. Use the “Force” function of the Unit Control to
energize the supply fan. Verify that it rotates in
the proper direction.
4. Insure proper compressor rotation
(see the follow-
ing instructions on "Verifying Compressor Rota-
tion").
Verifying Compressor Rotation
This unit uses scroll compressors,
which will only operate in one di-
rection. Failure to observe these steps
could lead to compressor failure.
The Versecon unit uses hermetic scroll compressors,
which only pump in one direction. Therefore, it is
necessary to verify proper rotation at unit start-up.
Operation of the compressor in the reverse direction will
not produce any capacity and cause the compressor to
cycle on internal overload. Operating the compressor
in reverse for ”extended” periods can result in failure
of the compressor.
To verify proper rotation, monitor the suction and
discharge pressure of each compressor system. Use
the “Force” feature of the Unit Control to turn on one
compressor system at a time. If there is a rise in the
discharge pressure and a decrease in the suction pressure
when the compressor is energized, the compressor is
properly phased and operating in the correct rotation.
If the suction and discharge pressure remain
approximately the same the rotation is not correct and
the phasing to the compressor must be changed. To do
this turn off the power to the unit and switch any two
of the three leads on the load side of the contactor for
that compressor.
Reenergize the compressor per above and verify the
discharge pressure rises and the suction pressure
decreases.
Suction and discharge pressure may be monitored under
the “I/O Points” in the User Interface or a refrigerant
manifold gauge set can be connected to each system.
INITIAL START-UP
After all the other preceding checks have been completed
the unit may be placed in operation.
1. Place the “On – Auto – Off” switch in the ON
position.
2. The supply fan will cycle on and permit compressor
operation if the air proving switch for the supply
fan has closed.
3. If there is a demand for cooling, supply air or sup-
ply and return air temperature depending on how
the unit is programmed, the first compressor will
start. After several minutes of operation, a flow
of refrigerant will be noted in the sight glass, the
vapor in the sight glass will clear, and there should
be a solid column of liquid visible in the sight glass
when the TXV stabilizes.
Startup