Installation and User Guide
18
Part No. 37-7760003
09-2018 18-HD48D1-1A-EN
but can be set in the range of -5 ° to 79°. Thermostat will
not allow a setting at or below the (dF) dual fuel setting.
If indoor temperature drops below 45° because of
a possible heat pump malfunction, the thermostat
will turn off the pump and switch to Auxiliary
heat. “Call for Service” will display on screen.
There are two ways the thermostat will return to normal
heat pump operation:
•
Press any key to retry the pump and erase the “call
for service icon.
•
When setpoint is achieved on Auxiliary, system will
return to heat pump operation on next call for heat.
From this point on screen reference numbers are specific to
either the 302 or the 303 model
38. (303 ONLY) Select Programmable Blower Balance Point
(bP) – Applicable with HP1 or HP2 selected, dF On with
outdoor sensor. Requires DHM connection from thermostat
to heat pump system. This feature de-energizes the DHM
terminal to operate the blower at a slower speed for first
stage heat when the outdoor temperature is below the
temperature selected. This circulates warmer air than the
higher fan speed. The default is 80° (disabled), but can be
set from 20° to 79°. Select an outdoor temperature where
the air coming out of the ducts begins to feel cool and the
thermostat will lower the fan speed to circulate warmer air.
39. (303 ONLY) Humidity Display (Hd) – Selecting HD On
enables the display to alternately show the current time and
the humidity. If HD is selected OFF, the display will not show
the humidity. (See page 10 for Humidity setpoint range)
40. (303 ONLY) Adjustable Humidity Display – The display
will show the ambient humidity and 00 (default). The
setting can be changed from -20 and LO to 20 and HI. The
displayed humidity will change as the offset is changed.
In Run mode, the displayed humidity will be the ambient
humidity adjusted by the setting selected.
41. (303 ONLY) Auto Humidity Reduction (HR) – This feature
automatically lowers humidity setting when the outside
temperature drops to prevent the interior windows/walls
from reaching the dew point where water condenses on
surfaces. This feature default is
OFF. It can be changed
to select
LO (low humidity reduction) or HI. To achieve
automatic humidity reduction, the thermostat lowers the
humidity when furnace cycles are long. When the outside
temperature rises, it increases humidity. “
LO” indicates a
low amount of humidity reduction.
42. (303 ONLY) Automatic Humidification (AH) – This
feature if enabled allows for humidification independent of
a call for heating – useful in arid climates where addition
humidification in heating and/or cooling is desired. If
enabled, will energize the humidifier and circulator blower
(
“G” terminal and the “HM” terminal) if the actual humidity
is below the humidity set point. The display indicates
AH.
Pressing the key will cycle the display from
OFF to H
(feature enabled in Heat mode) to
C (feature enabled in
Cool mode) to
A (feature enabled to Auto mode) and back
to
OFF.
43. (303 ONLY) Cycle Humidifier (CH) – This feature provides
an option that reduces the water usage by up to 50% when
a flow-through humidifier is controlled by the thermostat. It
is recommended for use on flow-through humidifiers only.
The display indicates
CH (Cycle Humidifier) with the default
indicating OFF. Pressing the or keys will toggle the
display from
OFF to On and back to OFF. When CH is
enabled, the humidifier will cycle to turn off for 10 minutes
after it has run for 10 minutes. The blower and/or furnace
will continue to run during the humidifier off period.
44. (303 ONLY) Programmable Dehumidification Optimal
Comfort Mode (OC) or Optimal Dehumidification (Od) –
This item can be selected to OC (Optimal Comfort mode),
Od (Optimal Dehumidification), or OFF. When Optimal
Comfort (OC) is enabled, this feature automatically reduces
indoor humidity with a call for Cooling if humidity is 2% above
humidity setpoint. Humidity is set by pressing the Humidity
key when in the appropriate mode, in this case Cooling,
and pressing the
or
keys to set desired humidity
(range 40% to 95%) level followed by pressing Humidity
key again. This dehumidification feature uses less energy
by maintaining temperature and dehumidifying only when a
call for Cooling is required. Optimal Dehumidification (Od)
when enabled, this feature automatically reduces indoor
humidity with a call for Cooling if humidity is 2% above
setting. Humidity is set by pressing the
HUMIDITY key when
in the appropriate mode, in this case Cooling, and pressing
the
or
keys to set desired humidity level followed by
pressing Humidity key again. This dehumidification feature
may use more energy by making dehumidification a priority
initiating a call for cooling if humidity is 2% above desired
setting. This feature may also over-cool the condition
space by up to 3 degrees to achieve the desired humidity
level. (Note: Both dehumidification modes operate in
Cooling mode only with a call for cooling)
45, 46 on 303 (38/39 on 302)
Change UV Lamp – This feature allows the thermostat
to display the words “Change UV Lamp” (Call for Service
of UV bulb) after a set time of UV bulb operation. This is
a reminder to maintain your UV system at optimum level
of operation. When enabled, the factory set interval for
“
Change UV Lamp” to be displayed is 350 days of UV
bulb operation and can be adjusted in 25 day increments.
This should be adjusted with respect to the bulb’s
recommended maintenance schedule. When “
Change
UV Lamp” is displayed, you can clear it by pressing Clean
Display.
47, 48 (303 ONLY) Change Humidifier Pad – This feature
allows the thermostat to display the words “
Change Pad”
after a set time of humidifier operation. This is a reminder
to maintain or clean your humidifier. The factory set interval
for “
Change Pad” to be displayed is 100 hours of humidifier
operation. This should be adjusted with respect to the
humidifier’s recommended maintenance schedule. When
“
Change Pad” is displayed, you can clear it by pressing
Clean Display.
49, 50 on 303 (40/41 on 302)
Select Change Filter Run Time – This feature allows
thermostat to display “
Change Filter” after a set time of
blower operation. This is a reminder to change or clean
your air filter. This time can be set from 25 to 1975 hours
in 25 hour increments. A selection of OFF will cancel this
feature. When “
Change Filter” is displayed, you can clear
it by pressing Clean Display. In a typical application, 200
hours of run time is approximately 30 days.
