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Author Topic: Zwave Differential Thermostat?  (Read 2346 times)

Offline aecchalet

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Zwave Differential Thermostat?
« on: August 25, 2016, 12:59:40 pm »
I have a very hot garage in a warm climate.  I would like to install an exhaust fan that would be triggered whenever the interior garage temperature is above 90F but also at least 4-5 degrees higher than the outdoor temperature.  (If both indoor and out door temps are 95F, I don't want to run the exhaust fan.) I have found some digital differential thermostats online but can't find one with zwave connectivity for remote control and monitoring.  Anyone know of one?  I suppose that I could also use my Trane zwave thermostat then write luup program to compare thermostat ambient temp with underground weather temp but I would prefer to use the temp on the shaded exterior side of my garage where my air intake would be place.  Perhaps a zwave outdoor temp sensor could be used instead of a distant temp from an Underground weather station.  Any suggestions would be appreciated but the simpler the better.  I am not an electrician or Lua programmer.

On further searching, I found a few thermostats that provide the differential function but none with zwave or zigbee connectivity:
http://www.ojelectronics.com/Business-Areas/Differential-Thermostat-PROD39.aspx is an analog version made in Denmark.
http://www.ledclocks.com/controllers/DSD2DifferThermostat.html this Kera product will turn on the fan at a given minimum temp and shut it off if the differential was greater than a set amount.  It retails for about $220.
http://www.sbesolartech.com/picdifftherms.html This unit only provides the differential function.  I would need to use the standard thermostat sold with the exhaust fan to turn on the fan when the temp got above 90F.  Then this device would open the relay (shut off the fan) when the temp differential was less than a certain set amount.  It can be bought for around $79-89 on eBay.
Another option is the RANCO ETC Temperature Controller.  This device has both target temp and a differential temp setting and can be purchased for around $49 on eBay.

Perhaps I could use the Homeseer HSM200 (AC plug in zwave temp monitor) for inside my garage and the Fibaro window door sensor battery powered (mounted on inside of garage door) connected to external temp prob DS18b20 for outside temp near my air intake and a zwave switch for the fan, controlled with Lua code or PLEG logic (as Richard suggested below).

With all of the trouble that I have keeping my zwave system operating 3000 miles from my main home and problems with sensors dying due to salt air corrosion and battery failure, I am leaning towards the RANCO ETC temp controller and perhaps the Homeseer HSM200 unit to remotely monitor the garage temp.
« Last Edit: August 25, 2016, 11:53:02 pm by aecchalet »
Vera Plus 1.7.2138; 12xHRDS1, 2xTrane SCHTZMT400 Tstats; 5xZIR00, 4xCA9000 PIRs; 2xHA01C Recept; 2x2wy ZDW120W switch; 1xAppl (ACT, GE/Jasco), 1xLite Dim Mod (GE/Jasco, Evolve);  2xDead Bolts Schlage

Offline Mike Yeager

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Re: Zwave Differential Thermostat?
« Reply #1 on: August 25, 2016, 03:00:50 pm »
A temp sensor in the garage with a switch to turn the fan on and off combined with the outdoor temp from the weather station and a bit of PLEG code would be the route I would take. The weather station may not be that distant and it's probably accurate enough.

Offline aecchalet

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Re: Zwave Differential Thermostat?
« Reply #2 on: August 25, 2016, 03:21:46 pm »
I would like to avoid battery operated devices.  The batteries don't last long in this hot, salty air environment and I only visit this vacation home 3-4 times per year.  I need this thermostat system to be more reliable than my battery operated sensor have been in that environment.  I just installed a solar inverter in that garage and am now parking Nissan Leaf there.  Neither of these are tolerant of the 110-120F temps that currently occur in that garage.  Is anyone aware of any plug in zwave temperature sensors that I could place in my garage and either locate another outside of my garage or connect a remote probe located outside but connected to sensor inside?
Thanks for your thoughts and suggestions.
« Last Edit: August 25, 2016, 11:54:11 pm by aecchalet »
Vera Plus 1.7.2138; 12xHRDS1, 2xTrane SCHTZMT400 Tstats; 5xZIR00, 4xCA9000 PIRs; 2xHA01C Recept; 2x2wy ZDW120W switch; 1xAppl (ACT, GE/Jasco), 1xLite Dim Mod (GE/Jasco, Evolve);  2xDead Bolts Schlage

Offline integlikewhoa

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Re: Zwave Differential Thermostat?
« Reply #3 on: August 25, 2016, 04:44:18 pm »
I would like to avoid battery operated devices.  The batteries don't last long in this hot, salty air environment and I only visit this vacation home 3-4 times per year.  I need this thermostat system to be more reliable than my battery operated sensor have been in that environment.  I just installed a solar inverter in that garage and am now parking Nissan Leaf there.  Neither of these are tolerant of the 110-120F temps that currently occur there.  Is anyone aware of any plug in zwave temperature sensors that I could place in my garage and either locate another outside of my garage or connect a remote probe located outside but connected to sensor inside?
Thanks for your thoughts and suggestions.

Not saying they are the best but one option for sensors that plugin is Aeon Multisensor. http://aeotec.com/z-wave-sensor

Most like the battery but there is alot of limitations when on battery (trying to conserve battery) but the sensor runs off usb or battery (only one at a time) It comes with a usb cord and can be plugged into any old phone charger wall work or something to that extent. It will give you motion, temp, humidity and more that maybe useful. On USB power you can set update rates very fast without having to worry about battery consumption. I wouldn't trust motion outdoors due to false alerts with wind, trees, changing lighting, but temp would be good as long as its not mounted in a place like high under the eve that heat from the roof and stail air gets high, false readings.

Offline aecchalet

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Re: Zwave Differential Thermostat?
« Reply #4 on: August 25, 2016, 09:34:09 pm »
Thanks for info on Aeon sensor with USB power.  I looked again today and found the HomeSeer HSM200 Z-Wave Multi-Sensor.  This plugs directly into a wall outlet.  It would probably give me indoor (garage) temp but doesn't look like it would last long outdoors.  I read in this forum that there may be a bug in the motion detection function but has anyone had problems with the temperature sensor?
Vera Plus 1.7.2138; 12xHRDS1, 2xTrane SCHTZMT400 Tstats; 5xZIR00, 4xCA9000 PIRs; 2xHA01C Recept; 2x2wy ZDW120W switch; 1xAppl (ACT, GE/Jasco), 1xLite Dim Mod (GE/Jasco, Evolve);  2xDead Bolts Schlage

Offline michelhamelin

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Re: Zwave Differential Thermostat?
« Reply #5 on: August 25, 2016, 10:03:02 pm »
Temp and humidity are ok, but motion sensor as a bug, i use it also at my cottage ( mon chalet) :)

Offline RichardTSchaefer

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Re: Zwave Differential Thermostat?
« Reply #6 on: August 25, 2016, 11:16:03 pm »
I live in Texas and also live with some extreme outdoor temps.
 
The weather underground plugin can be used to get outdoor weather from a station near you ... often within a couple of miles from you.

I have a shop ceiling fan. Depending on outdoor temp I open the garage door about 1 foot (when the outdoor temp is > 50)  ... and fire up the fan.
This starts at about 2 hrs before sunset and stops at 30 minutes after  sunset.  This cools the shop to around the low temp of the day.
Then it closes the door. Of course this does not happen when I am not home (i.e. the shop alarm system is armed.)

I also use exhaust fans to cool the house in the Summer and Spring.
When my windows are open, the House Thermostat and Outdoor temp controls the exhaust fans. (The HVAC is turned off)
With the windows close the Thermostat controls the HVAC.

There are also notifications on when I might Open and Close windows based on Outdoor Temp and indoor Thermostat setpoints.

All of this is done with PLEG logic.
I do have my own weather station ... So the weather underground plugin uses my own weather station.