JOHNSON CONTROLS
88
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
SECTION 3 – START-UP
TABLE 12 -
SETSCREW TORQUES
SETSCREW DIAMETER
TORQUE MIN.
(FT.- LBS)
#10
4.3
1/4 inch
10.0
1"
20.0
3/8"
25.0
17. Verify that all mechanical and electrical inspec-
tions have been completed per local codes.
18. Make sure the trap for the main evaporator drain
pan has been primed by pouring water in the pan
until water exits the condensate drain line.
19. 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 In-
terface.
UNIT CHECKS – POWER APPLIED
1. Apply 3-phase power to the unit and verify it falls
within the voltage range given in
2. Check for voltage imbalance. Voltage imbalance
should not exceed 2% of the average voltage.
3. Use the “Force” function of the Unit Controller 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
The 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 does not produce
any capacity and cause the compressor to cycle on in-
ternal overload. Operating the compressor in reverse
for “extended” periods can result in failure of the com-
pressor.
To verify proper rotation, monitor the suction and dis-
charge pressure of each compressor system. Use the
This unit uses scroll compressors, which
only operate in one direction. Failure to
observe these steps could lead to compres-
sor failure.
“Factory Run Test” feature of the Unit Controller 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 approxi-
mately 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 dis-
charge pressure rises and the suction pressure decreases.
Suction and discharge pressure may be monitored un-
der the COMPRESSOR SYSTEMS key of 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 com-
pleted the unit may be placed in operation.
1. Place the “ON – AUTO – OFF” switch in the ON
position.
2. The supply fan cycles ON and permit compressor
operation if the air proving switch for the supply
fan has closed.
3.
If there is a demand for cooling, the first compres
-
sor starts. After several minutes of operation, a
flow of refrigerant is noted in the sight glass, the
vapor in the sight glass clears, and there should be
a solid column of liquid visible in the sight glass
when the TXV stabilizes.
4. Allow the compressor to run a short time, being
ready to stop it immediately if any unusual noise
or adverse conditions develop.
5. Check the system operating parameters by check-
ing evaporator superheat and condensing sub-
cooling. The leaving condenser water tempera-
ture should be between 85.0°F and 95.0°F when
checking subcooling. Connect a gauge manifold
set to the Schrader service valve connections on
the suction and liquid lines of the refrigerant sys-
tem to be checked. After the system is running and
the pressures have stabilized, measure the tem-
perature of the liquid line between the liquid line
drier and the expansion valve and the suction line