Fan control on thermostat

[gizmotronic]

I have a Nest Learning Thermostat v4, and it’s configured to control the fan on my furnace. It’s a single-speed fan.

In the Home app I see a control for a variable speed fan. This control doesn’t do anything as far as I can tell.

In the Eve app there is rotation speed control in the Thermostat section, and a Ventilation Fan section with both a switch and another speed control. None of these seem to do anything, either.

I’m not sure where to go from here. Should I expect that this works? If so, can I help diagnose this in any way?

[n0rt0nthec4t]

The "variable" speed fan control should still control you fan, even if single speed. It'll either be on or off ie: if you drag the variable speed fan to 0, it should turn off

If not we can look at diagnosing further. And perhaps an option enhancement down the track could be just on/off fan support for non variable speed fans

[gizmotronic]

That’s what I had tried, but it definitely neither responds to the fan control in the Home app nor reliably reflects the current state of the fan.

Here’s where it gets interesting. In the process of collecting data I tried several combinations using the Google Home app to control the fan to see if either Home or Eve showed the current fan state. It seems I can now turn the fan on and off in the Eve app by simply setting the variable speed control under Thermostat to 100% or 0%, respectively. It definitely didn’t do this earlier. The variable fan speed that I set in the Thermostat is also reflected in the Ventilation Fan section, and the Active toggle is set as expected. Finally, I’ll note that I can’t set anything other than 0% or 100% for the fan speed in the Eve app.

Even with things in this state the fan speed control in the Home app still doesn’t have any effect. I’m able to set any speed I like with no effect, and nothing is logged in Homebridge.

[n0rt0nthec4t]

OK. I'll go back and test against my single speed fan setup first (Nest Thermostat E though) and see if thats still correct (Winter here, so no need for fan atm)

After that, we can see where things are at

[n0rt0nthec4t]

Ok. think found out why :-) small coding error

Would you be happy to test an alpha channel version? Would probably need to remove the accessory from HomeBridge cache also

[gizmotronic]

Sure, no problem. Point me in the right direction, boss.

[n0rt0nthec4t]

[email protected]

[gizmotronic]

Problem solved. Thank you!

A few nice-to-have enhancements would help the non-techies in my household with the transition away from the homebridge-nest plugin:

• As you noted, an option to make it a switch rather than a variable fan speed control
• An option to break the fan switch out as a separate accessory
• An option to set the run time of the fan (it’s fine if it’s wired into the configuration, no accessory needed)

If you’re willing to consider these, I can open one or more issues to track them. Let me know what you think.

[n0rt0nthec4t]

That’s great to hear.

I’ll look into point 1

Point 2 can already be done via HomeKit itself.

the runtime is set at 15mins to align with the Nest app. Can see what effect has it makes or configurable

[gizmotronic]

Thanks! I do see now that I can break out the fan as a separate accessory in HomeKit, as well. I had no idea.

The Google Home app wants me to select a run time, then hit Run Fan. It starts at 15 minutes but has a list of times, at least on my 4th gen.

[n0rt0nthec4t]

What range of values does it allow??

[gizmotronic]

• 15m
• 30m
• 45m
• 1h
• 2h
• 4h
• 8h
• 12h
• 1d
• 3d
• 5d
• 1w

[n0rt0nthec4t]

The current code uses what ever fan runtime has been configured via the app, so if you change the runtime via Nest App or Google Home it would us that setting. I that suitable or should it be configurable in this plugin?

[n0rt0nthec4t]

Also, next alpha will have the desired change for the fan.. single speed will just be on/off

[gizmotronic]

Ah, whatever I set in the Google Home app is “sticky.” That works for me. It’s probably worth documenting that behavior explicitly.

[n0rt0nthec4t]

try [email protected]

probably have to remove the thermostat/fan again from cache, Even though I'm removing some things internal, not quite yet reflected in HomeKit dynamically, so hence the need to remove from cache (atm)

[gizmotronic]

Looks good to me. Thank you for taking care of this, and for your patient explanations!

[n0rt0nthec4t]

You welcome.. It was a good suggestion about the fan for a single speed also, so worth while fixing

Thanks for raising the other issue also with the fan, as allowed me to chase down a bug!