Hello, I have several ADC T2000 thermostats controlling a combined radiant and forced hot air heating system. Radiant heat is configured as the first stage and forced hot air is configured as the second stage. I have the Heating Differential set to 2 degrees.
The problem I have is that the Heating Stage Delay turns on the second stage regardless of whether the 2 degree Heating Differential has been reached. The maximum setting for Heating Stage Delay is 60 minutes, so the second stage always turns on 60 minutes after the first stage. This uses more energy than necessary.
Is there a way to extend the Heating Stage Delay beyond 60 minutes, or disable it? I would like to set this to several hours during the main heating season and turn it off during the shoulder heating season. If I am able to do this, the second stage would only turn on id the Heating Differential of 2 degrees is reached, or after the several hour delay. Ideally I would like to be able to select 2, 4, 8 or 24 hour Heating Stage Delay, or disable this setting entirely.
No, there is no way to disable it to my knowledge. It is a feature to make sure the system isn’t inefficient and running without being able to hit the target. The staging delay and the differential will both control when the next stage kicks in whichever is reached first.
So as it currently stands, if the first stage can’t keep up and the temperature has fallen 2 degrees before the staging delay is reached despite a heat call, the second stage will kick in.
If the first stage can’t keep up and the heat target hasn’t been reached within the staging delay (60 minutes for your setting) then the second stage kicks in.
While heat pumps or radiant heat systems are definitely on average more efficient than a furnace, that efficiency usually goes out the window if it has to constantly run without reaching the target. I think something like 4 to 24 hours as a staging delay would be beyond the efficiency benefits of any system I am aware of, I am not an HVAC expert though.
What type of radiant heat do you have out of curiosity? I know there are a variety and some are more efficient than others. I’m happy to send feature requests to ADC, it helps to have the use case.
There is no way to accomplish that with strategy thermostat has built in. You could possibly do that with t3000 but it will have to be on a different hub so all parameters can be accessed. ADC does not offer that with ADC panels.
But beside the point. What you can do with what you have is to put a relay to open stage 1 wire when stage 2 wire gets energize. That way stage one will turn off when stage 2 comes on. once stage 2 satisfy temperature it will turn everything off. next heat call stage one wire would be close and start in stage 1 until stage 2 has to be energize again. Simple little wiring trick that will give you what you asking for.
Thank you for this information. I have an air-to-water heat pump from Enertech. When the radiant heat runs the water temperature varies from 80 to 110 degrees based on the outdoor temperature. When the forced hot air (stage 2) is turned on, the water temperature is fixed at 125 degrees, so this consumes much more energy. The manufacturer suggests that it is best to run the system with radiant heat even if that means it needs to run most of the time. During warm periods I can accomplish this by setting the number of stages to 1 in Installation Settings on the thermostat, but this is not ideal as I need to change back to 2 stages when the temperature drops.
If there is any way to make feature enhancement suggestions to alarm.com, I would like to be able to change the stage 2 delay to longer intervals of 2 hours, 4 hours, 8 hours, 24 hours and disabled. It’s just a user interface change and should not be difficult to implement.
Thank you also for the relay suggestion. I will look into this.