Multiple Zone Humidity Readings?

[ekobres]

I have a 2-zone Infinity Greenspeed system. From what I have been told, only the main thermostat has an active humidity sensor. The remote sensor displays humidity, but according to Carrier, the humidity reading comes from the main thermostat only. I sort of believe this because the zone cards in the Carrier app always show the humidity as the same number. Oddly, without changing the offset, it was closer to the remote sensor - but since I have adjusted the offset it does seem to track with the humidity in the main area. (I had to adjust the offset by a whopping 9% to get it to match!)

In observing the humidity sensors (1 per zone) provided by this integration, the numbers at first always seemed to stay in sync. However, when you plot them in history they sometimes diverge by a fair amount. My question is: does anyone have any idea how this actually works with what is being reported by the API? Does anyone know why Carrier thought it would be a good idea to only have one humidity sensor in a zoned system? My second zone is a finished basement, and is always significantly higher humidity at any given temperature. Right now I'm experimenting with an automation to run the AC with the fan at low speed when the humidity gets high - I'll have to watch it over time to see if that helps.

Anyway, just curious if anyone has any experience on insight with this.

Thanks!

[LSR19]

I have a 3-zone system with one 25VNA fully variable Greenspeed HP. The humidity for all zones is whatever is sensed by the master controller in its zone. I have no idea why Carrier doesn't include a humidity sensor in its remote smart sensor. Makes no sense to me.

I have the same problem you have. One zone is my finished basement with higher humidity than the rest of the house. I tried doing what you are trying - using the AC to bring down the basement's humidity. For sensors, I used 4 Govee temperature-humidity sensors disbursed in 4 rooms of the basement. An automation tracks the real-time average humidity of the 4 Govee sensors as well as the max humidity of whichever Govee is reporting the highest humidity at the moment. Originally, I used this data to turn on/off the AC basement zone to bring down the humidity. Reliably turning the zone on or off required the automation to set the temperature set point of the basement zone 2-degrees below or above whatever the Carrier remote smart sensor was reporting. But using the AC to control basement humidity created a different problem - the basement became and stayed uncomfortably cold.

Eventually, I abandoned using the AC to control basement humidity by installing a whole-house dehumidifier. The dehumidifier, controlled by my humidity sense automation, sends dehumidified air through the basement ducts as needed. To prevent the basement from getting too cold, I keep the basement zone damper closed 24x7 by setting the basement cool setpoint to 90-degrees (i.e., essentially 'off').

The dehumidifier approach has worked really well. The basement's humidity is now maintained at a suitable level, and it never gets too cold. The only downside to the dehumidifier is it was expensive to install. But its cost is likely much less than what it would cost for mold remediation due to years of excessively high humidity.

[ekobres]

For a top-of-the-line system that claims to control humidity, this is pretty wild to me, especially since there actually is a humidity sensor in the remote thermostat. It displays humidity in the UI, Carrier just doesn't do anything with it.

I have considered swapping the thermostat and the remote thermostat, making zone 2 the main zone to see if that works any better.

I have noticed there is a substantial difference in humidity control between the EFF and Comfort settings in the service menu. I think it has to do with how far down the compressor stages, which controls the evaporation coil temperature. The EFF mode is not as cool, but uses less power and a lower fan speed. I measure the condensate pumped from the unit with an automation, and I would say it removes approximately half the water when it's in EFF mode versus Comfort mode.

I haven't given up yet!

[HRoss226]

Comfort mode refers to indoor airflow and is about 325 CFM per ton of outdoor capacity, and Eff (efficiency) is about 350 CFM per ton. Lower airflow across the evaporator coil results in a lower supply air temperature. Lower temperature air cannot hold as much moisture, so more moisture drips out as condensate. The supply air now has less moisture. When it mixes with air in the space and warms up to that temperature, the percentage is lower because the air molecule is larger when warm so the percentage of moisture is now less.

[ekobres]

Comfort mode refers to indoor airflow and is about 325 CFM per ton of outdoor capacity, and Eff (efficiency) is about 350 CFM per ton. Lower airflow across the evaporator coil results in a lower supply air temperature. Lower temperature air cannot hold as much moisture, so more moisture drips out as condensate. The supply air now has less moisture. When it mixes with air in the space and warms up to that temperature, the percentage is lower because the air molecule is larger when warm so the percentage of moisture is now less.

The GreenSpeed unit is always tuning fan speed and compressor speed - so comfort is probably a "both/and" thing to keep the coils at an optimum condensation temperature, but also operate with a smaller dead zone to stay closer to the set point. The way these settings work on older infinity multi-stage systems is quite a bit different than how the newer DC inverter systems work.