Emerson Sensi Use and maintenance manual

SENSI™SMART THERMOSTAT
Humidity control guide
Models: 1F87U-42WF, ST55, NH-AWIFI, OH-AWIFI
Version: April 2023 Emerson Electric Co. All rights reserved
R-5622

Sensi smart thermostat | HUMIDITY GUIDE 2
1. CONTRACTOR FIRMWARE UPDATE PROCESS
Connect the thermostat to Wi-Fi, register to the customer's account to make
sure the thermostat has the latest firmware release.
2. INSTALLATION – COMPATIBILITY AND WIRING
SENSI THERMOSTAT CONVENTIONAL SYSTEM CONNECTION HEAT PUMP SYSTEM CONNECTION
RC†Power for cooling, 24V Power for cooling, 24V
RH†Power for heating, 24V Power for heating, 24V
CCommon wire, 24V Common wire, 24V
Y1st stage cool 1st stage heat and cool (compressor)
Y2/* 2nd stage cool
(or humidifier) 2nd stage heat and cool (or humidifier)
W/E 1st stage heat 1st stage auxiliary/emergency
heat (2nd stage heat)
W2/* 2nd stage heat
(or dehumidifier) 2nd stage auxiliary/emergency heat (3rd stage heat or dehumidifier)
GIndoor blower (fan) Indoor blower (fan)
O/B
Heat pump changeover, zone panel
or 3-wire hot water zone valve
connection. (configurable as O, B
or 2 in the installer menu)
Heat pump changeover (reversing
valve) connection (configure as
O or B in the installer menu)
Lno function “L” terminal connection

Sensi smart thermostat | HUMIDITY GUIDE 3
1.
W2/* TERMINAL DE-ENERGIZES ON CALL
FOR DEHUMIDIFICATION WITH CALL FOR COOL
2.
Y2/* TERMINAL ENERGIZES ON CALL
FOR HUMIDIFICATION WITH CALL FOR HEAT
HUMIDIFIER
Valve 24V
RC
RH
O/B
Y
G
W/E
C
L
Y2/*
W2/*
FURNACE/AIR HANDLER
TERMINAL STRIP
THERMOSTAT
SYSTEM
TRANSFORMER
LINE VOLTAGE
COMMON
HOT
R
C
W
Y
G
DHUM
1-WIRE HUMIDIFICATION & DEHUMIDIFICATION
DEHUMIDIFICATION WITH RELAY INSTALLED
FURNACE/AIR HANDLER
TERMINAL STRIP DHM
THERMOSTAT
RELAY
90-293Q
OR EQUIVALENT
NORMAL HIGH
MED
DEHUM
SPEED FAN
LOW
HEAT FAN OUTPUT
N
COOL FAN OUTPUT
1. NORMAL COOL SPEED POSITION (DHM ENERGIZED)
2. DEHUM SPEED MODE (DHM DE-ENERGIZED)
NO
NC
1
2

Sensi smart thermostat | HUMIDITY GUIDE 4
3. CONFIGURATION – SETTING HUMIDIFICATION/DEHUMIDIFICATION CONTROL CAPABILITY ON/OFF
CONFIGURATION MENU ITEMS REFERENCE
Display
Code Menu item Default Options
Wireless setup
Connects thermostat to wi-fi network — Connect
Fahrenheit or celsius F F
C
Outdoor equipment configuration
Cooling or heat pumps AC2
AC1 – Conventional cooling 1 (single-stage)
AC2– Conventional cooling 2 (two-stage)
HP1 – Heat pump 1 (single-stage)
HP2 – Heat pump 2 (two-stage)
AC0 – No cooling
Indoor equipment configuration
For gas or electric heat EL2
EL1– Electric 1 (single-stage)
EL2– Electric 2 (two-stage)
FAn
GA1 – Gas 1 (single-stage)
GA2 – Gas 2 (two-stage)
Reversing valve position
Selects “O” or “B” setting
For heat pumps only
O
O
B
2
Fn Circulating fan OFF Off/10% – 100% (5% increments)
H AA Humidification
Add accessory OFF Off/On
H SP Humidification
Set point OFF Off/5% – 50% (5% increments)
dH AA Dehumidification
Add accessory Od
Od/Oc
Od – Optimal dehumidification
(overcool to dehumidify)
Oc – Optimal comfort (wired dehumidification)
dH SP Dehumidification
Set point OFF Off/40% – 95% (5% increments)
Wireless radio
Turns wi-fi radio on/off ON Off/On

Sensi smart thermostat | HUMIDITY GUIDE 5
HUMIDIFICATION CONTROL AT THE THERMOSTAT
Ensure HVAC settings are single stage
To set up a wired humidifier accessory on this model, you will need to ensure that you have configured the HVAC
settings for single stage first. (Single stage cooling to use a humidifier or single stage heating to use a dehumidifier.)
If you have the thermostat configured for multi-stage, the humidity control options won't be in the menu.
Setting up wired humidification
With the thermostat showing the room
temperature, press Menu.
Press Next 7 times.
Use the Up Arrow button to toggle Humidity On.
Press Next.
Use the Up Arrow button to change the set percentage
(SP) to your desired percentage to maintain.
Press Exit.
Setting up wired dehumidification
With the thermostat showing the room
temperature, press Menu.
Press Next 8 times. - This may be different depending on
what other settings you have. Look for the "dH AA" menu.
Use the Up Arrow button to toggle Dehumidity "On."
Press Next.
Use the Up Arrow button to change the set percentage
(SP) to your desired percentage to maintain.
Press Exit.

Sensi smart thermostat | HUMIDITY GUIDE 6
HUMIDIFICATION CONTROL IN THE SENSI APP
Adjusting the humidity features from the Sensi app
After initially turning the feature on in the thermostat menu, you can edit them from the Sensi app.
Open the Sensi app.
Tap your Thermostat Name.
Tap the Settings Gear.
Tap System Settings.
Scroll to the Humidity Control section.
You can toggle the humidification features on/off
here, as well as adjust the set percentage.
*If you don't have wired dehumidification configured,
you will have a different dehumidification
option here that you can utilize. It will use your
cooling system to remove moisture from the air
by overcooling your space up to 3 degrees.

Sensi smart thermostat | HUMIDITY GUIDE 7
Frequently asked questions
FAQ ANSWER
When can I get the firmware OTA
update for humidity control? OTA updates are pushed via Wi-Fi after being registered to the customer's account on the Sensi app.
Which versions of Sensi thermostats are
compatible with humidity control?
Sensi Touch (1F95U) and Sensi (1F87U) smart
thermostats are all backward compatible. 1F86U
and UP500W models are currently not compatible.
What terminals should I use to
enable humidity control? Use Y2/* for humidification and W2/* for dehumidification.
What types of humidifiers and
dehumidifiers are supported?
Humidifiers: Any 24VAC humidifier. Currently,
Sensi does not support independent
(call for heat) humidification.
Dehumidifiers: HVAC systems with dehumidify
mode (slowing of the system's fan speed) or 24VAC
dehumidifiers. Currently Sensi does not support
independent (call for cool) dehumidification.
What is an appropriate humidity setpoint?
Depending on the outdoor temperature, the
ideal indoor humidity level is between 30-50%
RH. In cold weather, if condensation appears on
your windows, lower the humidity setpoint.
What is overcooling to dehumidify?
On air conditioning systems without a
dehumidifier, the dehumidification feature allows
Sensi to overcool to a maximum of 3⁰ below
the AC setpoint to help control the humidity.
Overcooling is an option to dehumidify without
having to wire additional accessories.
Why is my system unable to reach
my humidity setpoint?
During extremely cold and dry or hot and
humid climates, your humidifier or dehumidifier
may not be able to increase or decrease
humidity enough to reach your setpoint
depending on the size of your equipment.