Portal econet_700humid

Humidity Settings and Display

The EcoNet Smart Thermostat is used to control equipment to heat and cool the space, and that is its primary function. The 700 or 800  Series EcoNet will also control some humidifiers and will also add functionality to cooling by enabling dehumidification functions.

In the first batches of the 700 Series thermostat, customers may have noticed a slightly higher than actual humidity reading on the screen. Reports of this led to an investigation and as it turns out, the elaborate packaging had something to do with this. Outgassing from the foam liner may have contaminated the humidity sensor. Depending on conditions, how long it was in the box and a few other variables, the calibration offset of the humidity sensor may need to be used.

If you feel the humidity is reading high, the first step is going to be to actually know the humidity. You will have to use a sling psychrometer or quality calibrated humidity measuring device to know the actual. You may now use the offset calibration to adjust the reading on the thermostat.

Open the settings page, and basic settings. You will see an adjustment offset for the temperature and humidity. Highlight the humidity offset and adjust it up or down, as much as 9.5% either way to correct the reading and operation. This calibration offset is there for you to fine tune the adjustment.

You may also adjust the temperature if it is off by a few degrees if you wish.

Dehumidification

In cooling mode, turning dehumidification on does a couple things. For all air movers except the RH2T Constant torque air handler. It will adjust the blower speed when the actual room temperature is within a degree of the set-point. Keep in mind the display only shows whole numbers and does round. Once the gap between actual and set-point is below 1.00 degrees, the indoor fan will progressively slow down by up to 15% to increase the latent removal.

You may also select overcooling. If you have the thermostat set to 74 degrees and cooling, you have a 2 degree overcooling setting, and the humidity is higher than the desired setting. The system will remain on below the set point to 72 degrees in an attempt to remove more moisture. The unit can also be triggered to come on below the sensible set point if its between the set point minus the overcooling limit and there is at least a 3% difference between your RH set point and the Actual humidity. The unit may very well cycle on humidity. In the first status screen you will see if its dehumidification or not.

Lastly the dehumidify drain timer will be set to stop the fan at the end of a call from any continuous fan operation settings for the time selected. This allows moisture in the evaporator coil to go down the drain and not be blown back into the air.

There is no provision currently to connect a whole home dehumidifier and control it. However if you have a whole home dehumidifier and it has an output to bring on the system fan, we can do that. The humidifier of your choice would need to control a relay with dry contacts. A jumper from the air handler R to the normally open contacts of the relay and returning to G on the air handler or furnace will do the trick. You will have to configure the system to accept this input to G using the settings screens and setting it to G input enabled ON.

Humidification

A humidifier tied to the equipment can be turned on and controlled through the furnace or air handler. It must be configured as to which modes you will allow it to run. In the east, often times humidification will only take place in heat mode, or heat and fan mode, but not in cooling mode.

Your choices on when the humidifier can be energized are Heat, Heat and Fan, or Heat and Fan and Cool. For dual fuel systems, the humidifier will be energized in either gas heat mode or heat pump mode.

The furnace or air handler have humidifier connections. This is a dry set of contacts so your source for humidity needs a power source whether it’s using its own power or you are using the equipment to power it. Don’t look for these dry contacts to have an output of voltage like EAC terminals. Review the instructions in the Air Handler or Furnace for wiring and set up.

Regarding steam humidifiers. The most common application for steam humidifiers will be to make sure your 700 Series Smart Thermostat has firmware revision "AC-RHUI-03-01-14" or later in it. If it does, you will set humidification to on, set to run in Heat/Fan and then Humidify with Fan set to a fan speed. This will allow a call for humidity to turn the air mover fan on, and close the HUM contacts even if the fan is set to auto and there is no call for heat. If you have earlier versions, you will need to run the constant fan in order to humidify when it's not heating.

Finally, a word on expectations. A bypass humidifier requires warm dry air to pull moisture from the pad. It works best with gas furnaces, OK with heat pumps and poorly at best in fan only modes. It wont do anything in cooling mode as the air in the stream is just as damp at that point. Don't just send water down the drain for no good reason. You may read where the water should be connected to the hot water line. That's up to you but it doesn't make it humidify in fan only mode any better.