Timed Fan Control w/ Air Circulation

[io_guy]

I thought I'd throw this one up.

I've setup my master bath fan on a 30 minute timer so that my wife doesn't leave it on all day after a shower.

I also wanted this fan (when its hot outside) to turn on for 10 minutes every hour to help air circulation in the house.

Then I needed code so that the "circulation" feature did not bother a standard bathroom user.

 

Here's what I did:

 

This program simply turns off the fan after it's running for 30 minutes.

It also resets the 30 minutes if you tap the fan on again.

Timer - Master Bath Fan:

If
       Control 'upstairsMasterBathFan' is switched On
    Or Status  'upstairsMasterBathFan' is On

Then
       Wait  30 minutes 
       Set 'upstairsMasterBathFan' Off

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

 

This program monitors the conditions to see if the fan should turn on for circulation.

Climate - Upstairs Fan A:

If
       From     9:00:00AM
       To       8:00:00PM (same day)
   And Module 'Climate' Temperature >= 20 °C
   And Status  'upstairsMasterBathFan' is Off

Then
       Run Program 'Climate - Upstairs Fan B' (Then Path)

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

 

This program handles the 10 minutes on per hour.

Climate - Upstairs Fan B:

If
  - No Conditions - (To add one, press 'Schedule' or 'Condition')

Then
       Wait  50 minutes 
       Set 'upstairsMasterBathFan' On
       Wait  10 minutes 
       Set 'upstairsMasterBathFan' Off

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

 

The final program interrupts the circulation programs if a user wants to use the fan.

Climate - Upstairs Fan C:

If
       Control 'upstairsMasterBathFan' is switched On

Then
       Stop program 'Climate - Upstairs Fan B'

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

[brad77]

Thanks for posting, io_guy. I'm about to install a whole house fan and I'm considering setting up timers for that to run for a short time in the evening. Once I get that installed, I'll refer back to your examples.

 

Now I've just got to address the issue of airflow. I don't want the fan to draw air from my fireplace! It would be nice if strategically placed vents could be opened in tandem with the fan starting up.

[dbroere]

Now I've just got to address the issue of airflow. I don't want the fan to draw air from my fireplace! It would be nice if strategically placed vents could be opened in tandem with the fan starting up.

 

you might consider monitoring the open/closed state of a a window or two and making the fan_ON conditional, based on the windows being open. There's no single device to do this but I believe it could be done with a magnetic sensor and an INSTEON device to measure the condition of the sensor.

 

If you do duct vent control, you're almost obligated to also do temperature measuring. you wouldn't want to trigger this process when it's 0-degrees outside. you also wouldn't want to do it when it's 90-degrees and real humid outside.

 

I've thought about taking the make-up air directly from the outside, rather than taking it from inside the house. You cool the attic but don't bring in cool air to the house. It's a trade-off. To get the whole thing NOT to do something inapropriate, you'd need temperature and humidity sensing. There's very limited outside/inside temperature, humidity, and time of day conditions when venting the attic air helps. That's what the programming flexibility is for.

[brad77]

Thanks for the ideas, dbroere. Once ELK support is fully available, I can use my M1 Gold to detect when windows are open. That coupled with some thermostat information could go a long way to getting the temperature in my home to a reasonable place at night. I suppose that I'd also have to be aware of whether it is raining or not, as I wouldn't want to draw any errant raindrops in through the windows during the half a dozen times that it rains here.

 

Thankfully, I don't really need to check the external temperature after sundown as I live in southern California. It's almost guaranteed that the exterior temperature will be lower than the internal (provided that the internal temp is above, say, 75 F) in the evening. Humidity is rarely a problem.

 

On that note, my fan has two speeds with the higher of the two requiring 220V. Has anyone had any luck with any of the high voltage relays from Smarthome?

[LeeG]

I have the SimpleHomeNet EZSwitch30 which switches 240V. It requires 120V to run the Insteon circuitry so a neutral is required. Sounds like you would have a neutral if the fan runs on other than 220. Smarthome just recently announced a 240V relay (even Dual Band) that does not require a neutral. A truly total 240V device. It is a new device so I doubt there is much experience with the device but SH has a good warranty.

[ingeborgdot]

What timer switch are you using?

[IndyMike]

On that note, my fan has two speeds with the higher of the two requiring 220V. Has anyone had any luck with any of the high voltage relays from Smarthome?

 

Hello Brad,

 

Rather than directly switching the input to your fan relay, could you parallel off the "fan request" from your thermostat? Most of the thermostat outputs that I have seen would allow this (open collector output). It would allow you to use a low voltage switch and keep the furnace "logic" for fan overrun timing, etc. intact. Note - this approach will not work with the newer "communicating" thermostats.

 

IM

[brad77]

Thanks, IndyMike. The fan install is in process and this is something I've considered. Provided the windows were open, I would love to have the thermostat kick off the fan based on the internal temp.

 

Though convenient, I don't know if it will work as I see a couple of problems with this approach:

 

1. The windows must be open or the fan will draw air from the fireplace/flue

2. I intend to use a Venstar thermostat with the INSTEON dongle

3. The outside temperature must be lower than the inside temp (or at least close to it) for the fan to be effective. Otherwise, you're just drawing hot air into the house

 

This fan will be an alternative to A/C. In fact, being somewhat close to the coast, I do not even have an A/C unit. As such, I should be able to leave the cooling contacts unconnected (they wouldn't go anywhere anyway) and monitor the "cool" request on the ISY. Then, it would check WeatherBug for external temperature, Elk for door/window open status (requiring the highly anticipated ISY Elk module), and fire up the fan if all conditions are met.

 

Stopping "cool" would shut off the fan.

 

I do not yet have a Venstar thermo. Does anyone know if it broadcasts the cool on/off requests to the ISY?

[IndyMike]

Sorry Brad,

 

I was mixing your post with IO_Guy's. I missed the fact that you were installing a Whole House Fan (thought you were activating the furnace fan for circulation).

 

Your 220V fan sounds rather massive. Are you sure you require a unit this size? I have a 120V whole house fan in the second floor of my 4500 sq foot house. During the spring I run this for roughly an hour prior to "sleepy time" to cool the second floor and attic. Don't remember the CFM rating, but I need multiple windows open a significant amount to prevent loading the fan.

 

Your approach of monitoring window status with the Elk is a nice touch to ensure you have some makeup air. However, this won't tell you how far your windows are open - i.e. a cracked window may provide an open status. If you have insufficient makeup air the airflow will be drawn from sources you don't intend (septic vents, bathroom vents, etc). If you have double hung windows (I have casements), you could monitor a second "open" position to guarantee minimum open area.

 

Sorry, I don't have any experience with the Venstar thermostats.

 

IM

[brad77]

No worries on the mixup. They are all good ideas.

 

The fan itself has a 1/2 HP permanent magnet motor that operates at two speeds, the second of which requires 220V. After evaluating it, I don't believe that I will be using the high speed mode because of the suction that it might create!

[ingeborgdot]

What timer switch are you using?

[io_guy]

What timer switch are you using?

 

Not sure who this question is for.

 

I'm using a standard switchlinc relay (no timer) and handling the timer portion within ISY programs.

[ingeborgdot]

A person could use the insteon timer also could they not and then program it to come on for 10 minutes a day like you do?

[Sub-Routine]

The KeypadLinc Timer can do this but the SwitchLinc Timer cannot.

 

Rand

 

A person could use the insteon timer also could they not and then program it to come on for 10 minutes a day like you do?

[ingeborgdot]

Is it pretty easy to do Rand.

 

By the way, how are you? I have been gone so much I have not had much time to play and have only forgotten things. I hate it when that happens.

[Sub-Routine]

Hi ingeborgdot,

 

I am doing well, thank you. I hope you are too.

 

The best part of home automation is when you can forget about it!

 

Rand

[brad77]

Quick update: Installed the fan and it really makes a difference! So far so good regarding INSTEON as well. No reliability issues to speak of while the fan is running...yet.

 

I was wrong about the voltage as well. The switch is rated for 250V in the "high" position, but the fan only uses a standard 110V power source.

 

I'll update if/when I get the timer/programs sorted out.

[ingeborgdot]

Will the 8 button insteon timer not work with a fantech inline bathroom exhaust fan?