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6.3.
Humiditrol Reheat Operation
A relative humidity sensor will energize first−stage compressor(s) and hot gas will be routed to the reheat coil based on the
setpoint set with ECTO 4.25 or from the L Connection network. The following options show additional conditions which must
be met before reheat will be energized:
ECTO 4.24 option 3
S
Blower energized.
S
Occupied time period.
S
One previous cooling demand must have occurred.
ECTO 4.24 option 5
S
One previous cooling demand must have occurred.
ECTO 4.24 option 6
S
Blower energized.
S
Occupied time period.
ECTO 4.24 option 7
S
No additional conditions.
Humiditrol reheat will de−energize when the RH drops to ECTO 4.25 minus 4.26. An optional RH sensor is required. See
figure 6. See tables 18 through 23 for reheat compressor staging. Shaded rows indicate reheat operation.
6.4.
Humiditrol Reheat Operation − Digital
ECTO 4.25 Set to 100
Humiditrol reheat is controlled by the digital input A55_P269_9 (M2) only. The input signal will energize compressor(s) and
reheat solenoid. Connect wiring to M2 as shown in figure 7. See tables 18 through 23 for reheat compressor staging.
6.5.
RH Measurement / Display
ECTO 4.24 option 4 When an optional relative humidity sensor is installed, the % RH can be displayed on the M2 readout
and over the L Connection network via the NCP and/or PC software. Option 4 is NOT used to control Humiditrol or Super-
market Reheat. Option 4 may be used for outside air dehumidification. Refer to figure 6.
USE 24 VAC (R) FROM ANY OF
THE AVAILABLE: P299−2, −5, OR −7
Figure 7. Humiditrol Reheat Diagram (ECTO 4.25 set to 100 for digital control)
6.6.
Outside Air For Dehumidification
The M2 has an option that allows FAT heated outside air to be used to dehumidify when outside air temperature is low. When
ECTO 4.24 is set to options 2−7, outside air will be used for dehumidification instead of the compressor. When the outside air
temperature is less than setpoint, ECTO 7.04 must be set to 70°F or less to enable this option. Additional conditions for
operation apply. See table 15.
The M2 will use the gas or electric heat to temper discharge air and the outside air will be used to dehumidify (when there is a
dehumidification demand and outside air is cool). Adjust the following settings:
ECTO 7.02 Outdoor Air Setpoint (50°F typical)
ECTO 7.03 Damper Position (40% typical)
ECTO 7.04 Fresh Air Heating Reheat Setpoint (65°F typical)
This option can be used with ECTO 4.24 options 2−7 only − not with option 1. Refer to table 17.
506457−01 05/10
R
7
D
DI−4
8
C
9
10
Page 20
6.
Reheat Operation
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