T606MSx-4 and T606MSx-4+PIR Series Multi-Stage Temperature and Humidity Controllers
Installation Instructions
6
Humidification Operation
Humidification operates only when the controller is in
heating mode (system mode = Heat, or system mode =
Auto and mode at the controller is Heat). If a call for
humidification occurs and the fan is off, the fan is first
turned on, then the humidifier output is activated.
In addition to reaching the humidity setpoint, the
following events can stop humidification operation:
•
RH sensor is out of range
•
System mode switches to Off or Cool
•
System mode is Auto, but the controller mode
changes from Heat to Cool
Humidity Setpoint Reset
The humidity setpoint reset function minimizes
condensation found on windows and building
structures during the colder months. An outdoor air
sensor connected at the controller is required for
humidity setpoint reset function.
When the outdoor air temperature falls below the
selected high temperature setpoint (RH HT), the
humidity setpoint decreases. The lowest humidity
setpoint is reached at the selected low temperature
setpoint (RH LT).
The Reset Humidity Setpoint (RE Sp) determines the
difference between the original setpoint and the lowest
setpoint. For example, in Figure 8, the reset humidity
setpoint is set to 20%; therefore, the humidity setpoint
decreased from 45% to 20%.
High Limit Humidity Sensor Operation
The T606MSx-4(+PIR) Series Temperature and
Humidity Controller includes a high limit sequence.
This sequence allows the use of a remote 0 to 10 VDC
humidity sensor to keep the humidifier from saturating
the supply air. The remote sensor throttles the output of
the Proportional plus Integral plus Derivative (PID) loop
if the high limit sensor measures humidity in the duct
over the high limit value (85%) less the proportional
band of the high limit PID loop. If no sensor is detected
at the high limit (HL) connector, this sequence is
disabled at the controller.
Dehumidification Operation
Dehumidification operation depends upon the
dehumidification lockout setting.
If Dehumidification Lockout (Dhu LCK) is set to On:
Dehumidification operates when the controller is in
cooling mode (system mode = Cool, or system mode =
Auto and the mode at the controller is Cool). If a
dehumidification demand exists and the fan is off, the
fan is first turned on, then the dehumidification output is
activated.
In addition to reaching the dehumidification setpoint,
the following events can stop dehumidification
operation:
•
RH sensor is out of range
•
System mode is switched to Off or Heat
•
System mode is Auto but controller mode is Heat
•
Room temperature falls below the cooling setpoint
less the deadband value
•
Outside air temperature falls below the
dehumidification outside air temperature lockout
value
0°F
20°F
-20°F
-40°F
FI
G
:RE
_sp
20%
25%
30%
35%
40%
45%
RE Sp = 20%
RH HT = 32°F
RH LT = -20°F
RH Set = 45%
%RH Se
tp
o
in
t
Outside Air Temperature
Figure 8: Humidity Setpoint Reset by
Outdoor Air Temperature
85%
F
IG:
HLH_
c
n
tr
l
0%
50%
100%
C
o
nt
ro
l O
u
tp
ut
L
e
v
e
l
Maximum Supply Humidity
Figure 9: High Humidity Limit versus
Control Output Level Curve
