Step 6 - Make Final Preparations; Ecm (Electronically Commutated Motor); Control Option - Carrier 42S Series Instruction Manual

If not included on the unit or furnished from the factory, supply
and return grilles should be provided as recommended in the prod-
uct catalog.
Step 6 — Make Final Preparations
1. Turn off power to the unit (open unit electrical disconnect).
2. Install thermostats and perform any other final wiring as
applicable. Check the unit for any loose wires.
3. Perform a final visual inspection. All equipment, plenums,
ductwork, and piping should be inspected to verify that all
systems are complete and properly installed and mounted,
and that no debris or foreign articles such as paper or drink
cans are left in the units or other areas. Clean dirt, dust, and
other construction debris from unit interior. Be sure to check
fan wheel and housing.
4. Rotate fan wheel by hand to be sure it is free and does not rub
housing. Check that wing nuts securing fan assembly to fan
deck are tight.
5. Ensure all panels and filters are installed before checking fan
operation. Turn on power to the unit.
6. Install filter in frame at front of coil. If field-supplied filters
are used, be sure size is as specified in Table 1.
CAUTION
Do not start up or operate unit without filter. Be sure filter and
unit interior are clean. Failure to do so could result in damage
to the equipment or building.
7. ECM (Electronically Commutated Motor) Blower:
If the unit is equipped with an ECM blower, additional steps
may be required during the air balancing process. The ECM
blower is controlled by one of three control boards, depend-
ing on the options ordered with the unit. Review project sub-
mittals or order acknowledgment to determine which ECM
control scheme the unit has. Alternatively, match the control
board to the illustrations identified in the Control Board Type
section.
8. Check the fan and motor operation.
9. Be sure drain line is properly and securely positioned and that
the line is clear. Pour water into drain to check operation.
10. Prior to the water system start-up and balancing, the chilled/
hot water systems should be flushed to clean out dirt and
debris which may have collected in the piping during con-
struction. During this procedure, the system should be
flushed from the supply riser to the return riser through a
cross-over loop at the end of the riser column, and all unit
service valves must be in the closed position. This prevents
foreign matter from entering the unit and clogging the
valves and metering devices. Strainers should be installed in
the piping mains to prevent this material from entering the
units during normal operation. Vent all air from unit coil and
related piping. Air venting from the unit is accomplished by
the use of the standard manual air vent fitting, or the
optional automatic air vent fitting installed on the coil. Vent-
ing can be accomplished by depressing the needle valve
core. Automatic air vents may be unscrewed one turn coun-
terclockwise to speed initial venting, but should be screwed
in for automatic venting after start-up operations. When
steady steam of water begins to escape, close valve. Vent
release air slowly, usually dripping water into drain pan in
the process.
Make sure all service valves are open and that the motorized
control valves, if supplied, are set for automatic operation.
The air vent provided on the unit is not intended to replace the
main system air vents and may not release air trapped in other
parts of the system. Inspect the entire system for potential air
traps and vent those areas as required, independently. In addi-
tion, some systems may require repeated venting over a period
of time to properly eliminate air from the system. Failure to
properly vent system may negatively affect operation.
11. Check all control valves in the system for proper operation in
accordance with valve manufacturer's instructions.
12. For units with factory-installed ball valves with lever handles:
When handle is perpendicular to valve body, there is no flow
through valve. Ball valves may be used as shutoff valves.

ECM (ELECTRONICALLY COMMUTATED MOTOR)

CONTROL OPTION

Both of the procedures described below require the control
box to be powered while adjustments are made. Line voltage
components are concealed behind a secondary cover. Howev-
er, installer should still take all reasonable precautions to pre-
vent electrical shock.
3-Discrete Speed Rheostat Field Adjustment (42SM Only)
The unit has been factory-configured to produce PSC equivalent
airflow on high speed, with medium and low speed set at 80% and
60% of high, respectively. If these setting are acceptable, then no
further configuring is required. Board mounted rheostats are pro-
vided to adjust the airflow pertaining to each output. Each output
can be adjusted from 0 to 100% of the motor's factory pro-
grammed operating range. To set airflow, connect a volt-meter be-
tween "common" (near the red status LED) and Flo1 through
Flo4. See Fig. 38.
Status
U3
Rp1
Com
Flo0
COMMON FLO1
Fig. 38 — ECM Rheostat Speed Board (42SM Only)
Carrier's convention is to preset and wire Flo1 for high speed,
Flo2 for medium, and Flo3 for low. Flo4 is not used with any stan-
dard thermostat, but may be employed for a more advanced appli-
cation. The chart on the control box cover associates airflow rates
with the voltage indicated on your volt-meter. For each speed, ad-
just the rheostat until indicated voltage matches the desired value
from the airflow table.
3-Discrete Speed Potentiometer Field Adjustment
Depending on the configuration, the 3-discrete will come with the
legacy control board or the 85 control board. The unit has been
factory configured to produce PSC (permanent split capacitor)
equivalent airflow on high speed, with medium and low speed set
at 80% and 60% of high, respectively. If these settings are accept-
able, then no further configuring is required.
27
CAUTION
CAUTION
Rp2 Rp3 Rp4
Flo1 Flo2 Flo3
FLO2 FLO3 FLO4
Rp5
Flo4