Installation Guide
18
11-HD14D1-9-EN
7.6 Humidifier Operation
The 850 has the ability to control a humidifier. Humidification
is only enabled while in heating mode of operation. Control
options are:
•
RH Control – When the indoor humidity is less than
the heating target relative humidity, a request for
humidification is sent to the indoor unit.
•
Frost Control – The 850 Control references the
outdoor temperature and structure integrity to offset
the heating target relative humidity. This helps to
limit the risk of frost or condensation from forming
on interior walls and windows. A scale of 1 to 10 is
provided based on the insulation properties and
expected leakage of the home (1=Leaky with poor
insulation, 10=Very Tight with good insulation). An
outdoor temperature sensor must be connected and
enabled for frost control to be available.
Frost Control Structure Integrity Scale
Leaky, Poor Insulation
Average
Good Insulation, Tight
1
2
3
4
5
6
7
8
9
10
The 850 Control can be setup to allow humidification
anytime in heating mode or only when actively heating.
The airflow during Humidifier-only is factory set to 100%
but can be adjusted between 35%-100% (this requires a
variable speed indoor blower). All humidifier control options
are located in the Installer Setup>Accessories Settings.
7.7 recovery
The 850 control utilizes a Stage Inhibit to limit equipment
staging. This inhibit can be defeated in the following two
manners. See “6.7 Stage Inhibits” on page 14 for more
information.
7.7.1 Aggressive recovery
Greater than 2
°
Setpoint Change
Disables stage inhibits in heating and cooling mode anytime
the setpoint is adjusted more than 2°F
7.7.2 Heating Aggressive recovery
By Outdoor Temperature
Disable stage inhibit in heating mode only when the outdoor
temperature falls below the selected outdoor temperature.
Note: If Aggressive Recovery is enabled, Heating
Aggressive Recovery is disabled.
7.8 Ventilation Operation
The 850 has the ability to control a Ventilation system
through the normally open dry AUX Contacts on the
optional Relay Panel. The blower is not interlocked on a
call for ventilation. The ventilation run time per hour can be
adjusted to meet ASHRAE 62.2 standards. A temperature
override can be set to prevent ventilation operation when
the outdoor temperature exceeds the minimum or maximum
outdoor temperature selections. If outdoor temperature
overrides are enabled the user can select to accumulate
the missed ventilation run time. Options are below:
•
Accumulate missed ventilation run time in 4
hour increments and make up when the outdoor
temperature is within the min/max settings.
•
Accumulate missed ventilation run time in 24
hour increments and make up when the outdoor
temperature is within the min/max settings
•
Accumulate missed ventilation run time in 4 hour
increments and make up at the end of 4 hour period.
•
Accumulate missed ventilation run time in 24 hour
increments and make up at the end of 24 hour period.
All Ventilation control options are located in the
Installer Setup>Accessories Settings.
7.9 Warm Air Discharge
Enabling Warm Air Discharge will reduce the variable
speed blower air flow by 20% when in compressor
heating operation. Warm Air Discharge only applies to
compressor heating and is disabled when hydronic, fossil
fuel or electric heat (including supplemental heat) modes
are activated. Warm Air Discharge can be enabled in
Installer Setup>Comfort Settings.
7.10 Wet Heat (Hydronic) Operation
A hot water coil can be applied to either a variable speed
or non-variable speed indoor unit. The hot water coil can
be the sole source of heat or used as auxiliary heat when
applied with a heat pump. When applied with a heat pump,
wet heat is considered auxiliary heat and will operate in-
conjunction with heat pump heat. Switching the system
mode to emergency heat would disable the heat pump and
cycle the wet heat only.
If applied with a variable speed air handler, the blower
speed during wet heat only heating will vary based on the
system load value. The airflow will range from 35% to 100%
depending on the system load value. When applied with a
heat pump, the blower speed during heat pump and wet
heat operation will be the higher of the two air flows. There
are separate blower “On” and “Off” delays for wet heat in
the 850 Control.
The 850 Control is designed to operate forced air systems
and should not be applied to non-forced air systems (radiant
floors, radiators, etc…)
The hydronic heat blower delay options can be accessed
by navigating to Installer > Setup > Airflow Settings.
