Ingersoll-Rand ReliaTel Скачать руководство пользователя страница 63

Страница: 63 / 176

RT-SVD03L-EN

setpoints. These will be used to determine the active
OA damper position target based on the space CO2
level in relation to the design and DCV CO

setpoints.

Space Pressure Control (Powered Exhaust)

For units with a PWM controlled supply fan, the user
will select an exhaust enable setpoint during the 100%
fan speed command. Once selected, the difference
between the exhaust enable setpoint and design OA
damper minimum position at 100% fan speed will be
calculated. The difference calculated will be used as an
offset to be added to the active building design OA
minimum position target to calculate the dynamic
exhaust enable target to be used throughout the supply
fan speed/OA damper position range.

Ventilation Override Mode

During ventilation override modes in which the supply
fan is commanded to run, the RTRM supply fan output
will be energized and the PWM signal provided by the
RTOM will correspond to 100% of the high speed
selection.

Dehumidification Control

Units configured with a PWM controlled indoor fan and
a two-speed compressor will utilize two forms of
dehumidification: Normal staged, hot gas reheat
dehumidification and enhanced dehumidification
without reheat.

Enhanced Dehumidification

Enhanced dehumidification (EDh) will be available on
all units equipped with a space humidity (SH) sensor,
regardless of whether the unit is configured with
traditional hot gas reheat (HGRH).

EDh will be accomplished on these units by utilizing a
SH sensor and selecting a dehumidification setpoint
(DhSp) on the RTOM and allowing ReliaTel™ to
determine when there is a need for dehumidification.
Once the SH value exceeds the DhSp and
dehumidification is enabled the unit will energize one
stage of compressor operation at 80% of the maximum
stage 1 airflow rating.

As with traditional HGRH, EDh will override the request
for 1st stage of cooling, but if there is a request for the
2nd stage of cooling, EDh will be disabled. If the
cooling request drops back below Cool 2, the unit will
transition back into EDh if the dehumidification call is
still present. If the dehumidification call is no longer
present, the unit will transition into Cool 1 and track
back into the Stage 1 airflow profile.

If during active EDh the SH falls below the DhSp - 2%,
dehumidification will be terminated and the unit will
transition back to normal cooling or heating control.
Once EDh terminates and there is no request for
heating, cooling, or ventilation, there will be a 60
second supply fan off delay in which the supply fan will
continue to run at the EDh speed.

Traditional Dehumidification with Hot Gas
Reheat

Traditional dehumidification with HGRH will also be a
supported option for this unit type. Units with this
option will include a reheat coil as on traditional
dehumidification units and will be controlled like a true
two-compressor system.

Units configured with a traditional HGRH coil will utilize
EDh as described above as the first stage of
dehumidification control if the SH is only marginally
high. If the unit is running in EDh and the SH drops
below the DhSp, EDh will be terminated and the unit
will transition out of the mode as described above. If
the unit is operating in EDh and the SH is not
recovering toward the DhSp, the unit will transition
into full HGRH until the SH falls below the SH setpoint.

During HGRH dehumidification both compressor
outputs will be energized simultaneously for full
capacity operation and the supply fan will be at the
user selected maximum speed. All existing overrides
and functional operations for dehumidification will
function as on units not configured for PWM signal fan
speed control. Note that a 60 second supply fan off
delay in which the supply fan will continue to run at the
user selected maximum speed will also be
implemented.

For units configured with traditional HGRH, SH and
Humidistat operations will be supported. However,
only units equipped with a SH sensor will utilize EDh as
the first step of dehumidification control. If the unit is
configured for HGRH under humidistat control, only full
HGRH dehumidification will be utilized; normal
dehumidification rules will be in effect for these units.

Service Test

For these units, troubleshooting of the motor control
can be performed by using the standard service test
mode as is currently offered on ReliaTel™ controlled
units. Refer to the table below for details about the fan
speeds associated with each step of service test:

Table 20.

Service test

Test Step

PWM Output

(a)

Fan On

50%

Econ

(b)

50%

Cool 1

82%