Venstar Cool Limit

[sperok]

Should the following code ensure that the AC can never be lowered below 78 degrees by manually pressing the Venstar buttons? It does not appear to be working reliably for me, getting confused by rapid button presses. This is a rental property, so user training is not an option.

 

If
       Status  'Heating and Cooling / Downstairs-Control' < 78° (Cool Setpoint)

Then
       Set 'Heating and Cooling / Downstairs-Control' 78° (Cool Setpoint)

Else
  - No Actions - (To add one, press 'Action')

[fitzpatri8]

That's expected. The thermostat isn't designed as a security apparatus, so it is naturally going to prioritize local input over remote signals.

 

You could work around this by using the signal from the thermostat to start a two minute timer to query the setting then raise it if necessary, provided the end-user isn't patient enough to keep holding the button for that long. Then again, the end-user could defeat that workaround by simply unplugging the thermostat adapter.

 

You could defeat this user workaround by installing two thermostats and adapters, one for user input and temperature reading that isn't actually wired to the HVAC and another, in a secured room, that the ISY controls based on input from the first. Creative users could still get around this by installing one of those old x10 thermostat setback heater units underneath the accessible thermostat to raise the perceived ambient temperature.

 

Why not just put a locking cover on the thermostat or have the tenant pay the electric bill?

[Goose66]

Er. . . yeah. The answer to your question was somewhere in there. Try this:

If 
       Status  'Heating and Cooling / Downstairs-Control' < 78° (Cool Setpoint) 

Then 
       Wait 5 minutes
       Set 'Heating and Cooling / Downstairs-Control' 78° (Cool Setpoint) 

Else 
  - No Actions - (To add one, press 'Action')

[sperok]

Thanks for the responses. WRT "Why not lock it and let the tenant pay the bill?" This is a vacation rental (3-30 days) so operation, training and payments need to be kept really simple. I want to keep the temps set "uncomfortable" when vacant and allow limited control when occupied. I also want to make sure the heat does not get turned completely off in the winter or AC left on in the summer.

 

The intent here is really to create a "locked cover" in software that will allow the up and down arrow keys to be pressed, but control the limits and make sure the modes stay set to AUTO. This is cost and damage control.

 

Currently I find the heat and cool setpoints modified to values between 0 and 100+, obviously not the intent of the end user or matching my desired operational model. My primary goal is to 100% reliably set upper and lower bounds, conscious of the ongoing discussion of Venstar issues.

 

Should the following approach be 100% reliable at keeping the thermostats limited between 50-70 heat and 78-98 cool? Noting that each key press on the Venstar either increases or decreases BOTH setpoints. The intent is for "TS-Query" to force a status update every 2 hours as a precaution against Venstar flakiness, then to have 4 seperate programs that test the min/max heat and cool limits. TS-Vacant will establish the setpoints at either the vacant or occupied settings based on changes to the variable $vacant which can be triggered by motion sensors or other means.TS-Mode will force the heat/cool and fan modes to auto in case the button on the front of the thermostat has been pressed.

 

Program: TS-Query

If
       From    Sunrise +  1 second
       To      Sunrise -  1 second (next day)
   And Time is Last Run Time for 'TS-Query' +  2 hours 

Then
       Set 'Heating and Cooling / Downstairs-Control' Query
       Set 'Heating and Cooling / Upstairs-Control' Query

Query the Thermostats every 2 hours, run at startup

Program: TS-Vacant

If
       $vacant is $TRUE

Then
       Run Program 'TS-Setpoints ' (Then Path)

Else
       Run Program 'TS-Setpoints ' (Else Path)

Program: TS-Setpoints

If
  - No Conditions - (To add one, press 'Schedule' or 'Condition')
Then
       Send Notification to 'Tell Spero'
       Set 'Heating and Cooling / Downstairs-Control' 50° (Heat Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Upstairs-Control' 50° (Heat Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Downstairs-Control' 98° (Cool Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Upstairs-Control' 98° (Cool Setpoint)
Else
       Send Notification to 'Tell Spero'
       Set 'Heating and Cooling / Downstairs-Control' 64° (Heat Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Upstairs-Control' 64° (Heat Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Downstairs-Control' 84° (Cool Setpoint)
       Wait  5 seconds
       Set 'Heating and Cooling / Upstairs-Control' 84° (Cool Setpoint)

Program: TS-CoolMaxLimit

If
       Status  'Heating and Cooling / Upstairs-Control' > 99° (Cool Setpoint)

Then
       Wait  1 minute 
       Set 'Heating and Cooling / Upstairs-Control' 98° (Cool Setpoint)

React to user pressing buttons, waiting 1 minute to "debounce" keystrokes

Program: TS-CoolMinLimit

If
       Status  'Heating and Cooling / Upstairs-Control' LT 78 (Cool Setpoint)

Then
       Wait  1 minute 
       Set 'Heating and Cooling / Upstairs-Control' 78° (Cool Setpoint)

Program: TS-HeatMinLimit

If
       Status  'Heating and Cooling / Upstairs-Control' LT 50  (Heat Setpoint)

Then
       Wait  1 minute 
       Set 'Heating and Cooling / Upstairs-Control' 50° (Heat Setpoint)

Program: TS-HeatMaxLimit

If
       Status  'Heating and Cooling / Upstairs-Control' > 70° (Heat Setpoint)

Then
       Wait  1 minute 
       Set 'Heating and Cooling / Upstairs-Control' 70° (Heat Setpoint)

Program: TS-Mode

If
       Status  'Heating and Cooling / Upstairs-Control' is not Mode Auto
    Or Status  'Heating and Cooling / Upstairs-Control' is not Fan Auto

Then
       Set 'Heating and Cooling / Upstairs-Control' Mode Auto
       Set 'Heating and Cooling / Upstairs-Control' Fan Auto

Force the Mode to Auto in case it gets changed manually

[Illusion]

Another option is to consider the Venstar Commercial line of the thermostats. 2700, 2800, 2900. These are designed to be security devices with cool set point limitation, heat set point limits, and keypad lock options. As this is done at the t-stat no programs or querys would be necessary and it should be 100% reliable with no education or interaction with renters.

 

They also can be security locked into program auto mode while still allowing limits on manual overrides.