NOTE:
The unit may appear to pulse with system static pressures greater than 0.5 in H2O.
The fan coil must be configured to operate properly with system components with which it is installed. To successfully
configure a basic system select the proper setting of the four Select Taps.
Cooling Select Tap
Select system airflow for cooling output. See figure 10.
Refer to Table 1 to select the proper airflow and Select Tap for the chilled water coil installed. Proper selection should be
derived from BTUH output of the coil from the unit specification sheet. The typical selection would be 350 to 400 CFM per
ton.
Heating Select Tap
Select system airflow for heat output. See figure 10.
Refer to Table 1 to select the proper airflow and Select Tap for the hot water coil installed. Proper selection should be
derived from BTUH output of the coil from the unit specification sheet. The typical selection would be 350 to 400 CFM per
ton.
Adjust Select Tap
Select system CFM airflow requirement. See figure 10.
Adjust select options are provided to adjust airflow supplied to meet individual installation conditions such as noise,
comfort and humidity removal. To provide airflow at rates described in Table 1, the Adjust Tap is factory set at nominal
(NORM). The adjust selections will regulate airflow supplied for all operational modes. The (+) tap provides 10 percent
airflow over nominal airflow selected and the (-) tap provides 10 percent airflow below nominal airflow selected.
Delay Select Tap
Select desired delay profiles. See figure 10.
Four operation delay profiles are provided to customize and enhance system operation.
NOTE:
The delay profiles are active only in the cooling modes.
Selection Options:
A
Arid Climates the motor is programmed with a minimum ramp time to achieve full cooling capacity within a short
time period. The off cycle delay is programmed with a reduced airflow over an extended time period.
B
- Mild Humid Climates the motor is programmed with ramp time and speed to achieve dehumidification on cooling
start-up, thus allowing more moisture to collect and drain from the coil. The off cycle delay is programmed with a
reduced airflow and short time period to enhance system efficiency and minimize re-evaporation of condensate.
C
- Humid Climates the motor is programmed with extended ramp time and reduced speed to achieve maximum
dehumidification on cooling start-up, thus allowing more moisture to collect and drain from the coil. There is no
off cycle delay programmed to eliminate re-evaporation of condensate.
D
No Delays the motor is programmed with no delays to represent normal operation of a standard air handler.
Heat Delay -
the motor is factory programmed with a pre-purge time to permit the circulator to circulate hot water to the fan
coil before the blower operates at a reduced CFM. The off cycle delay is programmed with a reduced airflow over a short
time period to post purge the heat out of the water coil and duct system.
NOTE: The unit does NOT read changes in COOL, HEAT, and DELAY taps while it is running. Disconnect power
for 1 minute before changing taps, then restart for the new settings to take affect.
Dehumidify Capability with Standard Dehumidistat Connection
Latent capacities for systems using the VMB-HW Fan Coil are better than average systems. If increased latent capacity is
an application requirement, the field wiring terminal block provides connection terminals for use with a standard
dehumidistat. The fan coil will detect the dehumidistat contacts opening on increased humidity and reduce its airflow to
approximately 80 percent of nominal cooling airflow. This reduction will increase the system latent capacity until the
humidity falls to a level, which causes the humidistat to close its contacts. When the contacts close, the airflow will return
to 100 percent of the selected cooling airflow. To activate this mode, cut the resistor located on the lower right hand corner
of the selection control board and wire in a standard dehumidistat. (Refer to figure 9.)
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