Hysteresis

[Cormacs]

Is there any way to change the hysteresis level in the Insteon thermostats? I have it controlling a pellet stove so it would be nice to have a little more temperature swing between calls for heat. Maybe someone has a program that would do the same thing?

[paulbates]

Unfortunately the HVAC features of the 2441TH are limited. There is not an adjustable deadband and its factory set at 1 degree (f)

The programming approach is: 
If
   lower temperature is reached
Then
   change setpoint to high end of your deadband 

If 
  higher temperature is reached
then
  change setpoint to the low end of your deadband (keeping in mind the 2441TH factory 1 degree deadband... this should be 1 degree higher than your target)

However, having tried the the 2441TH a number of years ago, I would advise against trying to program your way around it and buy a more sophisticated tstat that has advanced features including adjustable deadband. Also, the 2441TH does not always consistently report activity.

Paul

[Cormacs]

I have been noticing this.

[TrojanHorse]

I like Paul’s approach and may do something similar when I switch to v5 where I believe the set point can be stuffed into a variable. In my garage sometimes I need it warm (e.g drying paint) and other times I set it lower to save energy. So I use a more brute force approach.

If thermostat is calling for nothing (triggered when set point is reached)
Then wait 1 minute
Set thermostat main mode off
Wait 20 minutes
Set thermostat main mode heat

With this my set point is preserved and I prevent short cycling on and off. I use the wait 1 minute in case I cranked up the heat and am still in the garage and want to lower the set point. It’s fewer button presses to change the set point when it’s still in heat mode.

I also have a program to turn the main mode off if the heat has been running for 60 minutes and then turn back to main mode heat after 20 minutes. This is a left over from when I had a flaky control board (didn’t know it so at first I blamed the insteon thermostat). The thermostat thought it was heating when in fact (I believe) the heater had locked out. This forced a retry to start it up.

My main HVAC in the house are not controlled by insteon thermostats since I don’t trust them enough.




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[larryllix]

Just move the controlling stat sensor further from the heating source.

 

It's hard to prevent waves of heat and cold but easy to create them.

 

Alternatively block the air circulation to the stat sensor with a shelf or piece of furniture underneath to slow down the circulation causing the stat to have a slow response. Turn off circulating fans in the stat room.

 

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[TrojanHorse]

Just move the controlling stat sensor further from the heating source.
 
It's hard to prevent waves of heat and cold but easy to create them.
 
Alternatively block the air circulation to the stat sensor with a shelf or piece of furniture underneath to slow down the circulation causing the stat to have a slow response. Turn off circulating fans in the stat room.
 
Sent from my SM-G930W8 using Tapatalk
 
 
 
 

Sounds too easy shouldn’t we first try foam insulation in front of the thermostat attached to a temperature-controlled-actuator? J/K


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[Cormacs]

So I think I have it working fairly reliably with programs and variables now. I used a few variables to accomplish my goal...

Stove On Temp = the desired high temp

Stove Off Temp = the desired low temp

I made this program to lower the setpoint when the stove reaches the desired temperature. 

Heat Off - [ID 0011][Parent 0012]

If
        $Garage_Temperature >= $Stove_On_Temp
    And 'Garage / Garage Thermostat - Main' Heat Setpoint is '$Stove_On_Temp Degrees'
 
Then
        Set 'Garage / Garage Thermostat - Main' Heat Setpoint '$Stove_Off_Temp Degrees'
 
Else
   - No Actions - (To add one, press 'Action')

Then I created this program to raise the setpoint when the desired low temperature is reached

Heat On - [ID 0010][Parent 0012]

If
        $Garage_Temperature <= $Stove_Off_Temp
    And 'Garage / Garage Thermostat - Main' Heat Setpoint is '$Stove_Off_Temp Degrees'
 
Then
        Set 'Garage / Garage Thermostat - Main' Heat Setpoint '$Stove_On_Temp Degrees'
 
Else
   - No Actions - (To add one, press 'Action')

Now the issue with this is I have found that the thermostat isn't reliably receiving the isy commands. So I made these two programs to confirm the thermostat has received the command. For these two programs I use two variable.

Before Query = The thermostat setpoint as the isy believes it

After Query = The actual thermostat setpoint as retrieved from the thermostat after the query

This first program sets the variables after a change in heating state.

Query - [ID 0017][Parent 0012]

If
        Program 'Heat Off' is True
     Or Program 'Heat On' is True
 
Then
        $Before_Query  = 'Garage / Garage Thermostat - Main' Heat Setpoint °
        Set 'Garage / Garage Thermostat - Main' Query
        $After_Query  = 'Garage / Garage Thermostat - Main' Heat Setpoint °
 
Else
   - No Actions - (To add one, press 'Action')

Then this second program evaluates the two variables and if they are the same then nothing happens. But if they are not the same it re-triggers the first program and the cycle continues until the thermostat has received the command from either of the first two programs

Compare Query - [ID 001C][Parent 0012]

If
        $Before_Query is not $After_Query
 
Then
        Run Program 'Query' (Then Path)
 
Else
   - No Actions - (To add one, press 'Action')
 

And then I made this last program to make setting the desired temperature easier. With one last variable. Keeping in mind I always want the low temperature to be 5 degrees lower than the high temperature.

Stove Setpoint = the temperature that I actually desire the room to be at

Stove Temperatures - [ID 0015][Parent 0012]

If
        $Stove_On_Temp is not $Stove_Setpoint
 
Then
        $Stove_On_Temp  = $Stove_Setpoint
        $Stove_Off_Temp  = $Stove_Setpoint
        $Stove_Off_Temp -= 5
 
Else
   - No Actions - (To add one, press 'Action')
 

 It seems like a lot of work but I am happy with it. The stove has been running all day today turning on at 15 degrees Celsius and turning off at 20 degrees Celsius. I am also open to suggestions if anyone thinks they can do it in a less complicated manor.

[paulbates]

I think that’s it. Nice job. I had 2 RCS X10 Thermostats and did something similar to get a 2 degree F deadband and cover for the spotty X10 communications. 

My suggestion is to put a temporary notification statement in the compare program to track how often it misses

Paul

[Cormacs]

I have. Not only did I make a notification alert for when the stove fires up and shuts down. I also have a program to count the seconds the stove runs and emails me run times.