Thermostat auto minimum temp range is too large

At the moment in the app for controlling temperatures, the closest “Heat to” and “Cool to” can be together is 5 degrees Fahrenheit. Could these be closer? I understand one doesn’t want to enter an oscillating state, but nowadays, with accurate and filtered temperature readings, two degrees is sufficient.

Welcome to the Wyze User Community Forum @thecscc!

While you may see that the two setpoints are seperated by a 5 degree Deadzone, in truth it is actually a 2 degree separation. Because the Temperature Differential has the potential to be set at 3° (above and below setpoint), the actual temp when the system stops will be within 2 degrees of the other setpoint.

If they make the Deadzone closer, they will have to remove the Temp Differential option as the actual temps would overlap the setpoints.

Okay, I see in my configurations (it’s a church that has 5 HVAC units), that the Temperature Differential is set to 0.5 degrees (this is likely the default since I don’t think I changed it). The parameter description says, “this setting determines how far from the set point the thermostat will allow the temperature to go before turning on or off.”

My first inclination was this should be small because I want the thermostat to strictly keep the temperatures I want. But think you are saying that in the auto mode, this forces the thermostat to maintain a tighter range than the program is set to. Am I correct?

For instance, if I set the heat to/cool to range to 70 to 75 and the temperature differential to 3, then the actual temperature range enforced by the thermostat is 72 to 73?

The Temp Differential is how exact you want your comfort to be.

The smaller the differential, the more often the system runs, but for shorter times - Less economical and harder on the equipment.

The wider the differential, the less often it runs, but for longer times - More economical and easier on your equipment.

In your example, with a Differential of 3°, set to 70\75: during the Heat State the system would call for heat and activate the system at 67° and heat to 73°; during cool it would call for cool at 78° and cool to 72°. That is 3° above and 3° below the setpoint for the Start\Stop.

At your current differential of 0.5°, the system will call for heat at 69.5° and heat to 70.5°, a one degree heat cycle. When cooling, it will call for cool at 75.5° and cool to 74.5°, a one degree cool cycle. This creates an excessive On\Off runtime and will wear out the equipment quickly, especially in a building that may be poorly insulated with low thermal retention. The equipment never gets a rest.

Yeah, neither of these situations are what we need. The closest the heat-to and cool-to can be should be a function of the differential. If the differential is 0.5, then the heat- and cool-to should be able to be as close a one degree.

I know that is super inefficient, and hard on the equipment, but we’re a church and during services, we need very tight temperature control. Outside of services we just don’t want things to freeze or get too hot. We only have services on Sunday mornings and Wednesday nights.

So it’d be great if you let users control things for their specific purposes.

The native logic in the control board on your system won’t allow that. Download the Technical Data for the Model of the HVAC unit you have installed. You will find that the manufacturer of the unit has already coded a Minimum Dead Zone between these settings that cannot be overridden. Even if the Thermostat allows it, the control board will not.

This is a “safety” mandate from the manufacturer. If the two setpoints are too close, your system will be jumping back and forth from Heat to Cool in a never ending cycle fighting each other for supremacy causing back to back startups in each mode. This will continue until you fry your system and have to replace it. That is not covered under warranty.

Your system, even in a large space - moreso in a small space, and directly affected by the accurate sizing of the system to the space, cannot react quick enough to small changes in temps at the thermostat. You would be short cycling your unit to death.

If you have issues with the heat or cool coming to temp too quickly or very slowly, the system installed may have been oversized or undersized for the space. That has to be calculated by an HVAC Expert.