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Shawn Pettersen

Technical Service Manager • North Georgia

Ecobee Setup

Ecobee thermostats provide multi-speed fan control to work with 2/4-pipe fan coil units with/without pipe sensors (24V systems only) and multi-speed PTAC units. These settings are accessed through the “I’m a Pro” setup flow. Many of the same first-run configuration steps apply as described in the “I’m a homeowner” section, however this section will callout and describe the key screens and settings.

First step is to determine the correct configuration for the application the ecobee is going to be controlling.

Fan Coil Unit (FCU) wiring on the ecobee:

4-pipe system

  • Y1: fan coil cooling
  • W1: fan coil heating
  • G2: medium-speed fan
  • G3: high-speed fan

2-pipe system

  • Y1: fan coil cooling/heat
  • W1: Aux Heat stage 1 or fan coil heat
  • G2: medium-speed fan
  • G3: high-speed fan
  • S1 & S2: dry contact terminals for the pipe sensor

Terminal activation for multi-speed fan control:

For multi-speed options, multi-purpose thermostat terminals will be utilized.

  • Y2 can also be configured as G2
  • W2 can also be configured as G3

For the pipe sensor:

  • Rh becomes S1
  • PEK becomes S2
  • Low speed – G1
  • Medium speed – G2
  • High speed – G3

Fan speed selection (System Mode):

  • Fan speed setting is located in MAIN MENU > SYSTEM > FAN SPEED
  • It is a global setting, meaning that it will affect all types of fan runtime (i.e. heating, cooling, fan only, fan + ventilator, fan + humidifier, etc.)
  • Optimized: When running heating/cooling the fan speed will be automatically adjusted based on heating/cooling needs, the system will attempt to use the lowest fan speed while maintaining comfort.
ecobee setup
Main menu > Gear icon > System > Fan speed
Main menu > Fan icon
Main menu > Fan icon

The Pipe Sensor:

The pipe sensor monitors the temperature of the water going to a 2-pipe FCU, also known as changeover sensor, changeover switch, Aquastat, among others:

• If the water is hot (> 83 F), it signals the thermostat that the system is in heat mode;
• If the water is cold (< 65 F), it signals the thermostat that the system is in cooling mode;
• User configurable for Open or Closed activation
• Compatible with both on-Cool / on-Heat sensors (determined on 1st run setup)
• Compatible with dry-contact pipe sensors (on/off), not analog. (ex. 10K ohm thermistor)

Multi-speed setup flow options during setup process:

Fan Coil Unit, no W1 wire

  • Y1 detected, O/B not detected
  •  2-pipe, no Aux Heat

Fan Coil Unit, w/ W1 wire

  • 2-pipe, w/Aux Heat
  • 4-pipe

Setting up an ecobee for dehumidification control:

This section describes how to setup an ecobee thermostat to control a standalone dehumidifier or a forced air furnace/air-handler that supports a ‘Dehum’ mode.

Once the ecobee has been wired to control the HVAC system and dehumidification system using the ACC+/ACC- terminals it will require correct setup to determine how you want to enable Dehumidification control. During the first-run setup they are a few key settings to ensure Dehumidification is part of the HVAC control algorithms.

Select Dehumidifier
One wire or two wire.
Select the relay state when active.

After the ecobee has been configured there are a few specific settings that allow you to determine when the Dehumidifier becomes active.

To access these settings, on the device select MENU > SETTINGS > INSTALLATION SETTING > EQUIPMENT > DEHUMIDIFIER.

  • Dehumidify with Fan (Yes or No): when Dehum is active this setting specifies if you want the furnace/air-handler fan to run as well. This will activate (G) output on the t-stat at the same time. This can work independent of a cooling cycle.
  • Min Runtime Delta (2-10%): to reduce short cycling, the dehumidifier will run beyond the desired humidity by the selected amount (%). Default is 5%.
  • Dehumidify in Heat Mode (Yes or No): If humidity is a concern during the heating season and have a standalone Dehumidifier, this setting can be used to activate the Dehumidifier and will work independent of a heating cycle.
  • Dehumidifier Active (Open or Closed): this setting is dependent whether the HVAC system or standalone Dehumidifier requires it to be open or closed while active. This setting is part of the 1st run setup but can change afterwards in the Dehumidifier menu.

AC Overcool Max is another option to help control high humidity levels and works in conjunction with the Dehumidify setpoint under System Mode menu. This setting will allow the Air Conditioner to overcool by comparing the actual RH% vs. the desired Dehumidify setpoint.

Note: When the overcool temperature has been achieved (i.e. temperature setpoint + overcool setting), the AC system will turn off however the Dehumidifier ACC+/- relay may be still active if Dehum setpoint has not been achieved.

That is the main first time start up on your new Ecobee thermostat. In our next article we will go over more features and options that the Ecobee has to offer.

Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion. 

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