[clug] Home automation interest

Neil Pickford neilp at goldweb.com.au
Thu Nov 12 12:01:50 UTC 2015


I have a Solahart 302J which I have added a 3rd K panel to so I suppose 
it is a 303JK - Anyway - See the picture.

The best location for a temperature sensor is the Tank Anode.  This 
gives you the mid tank temperature and is similar to the temperature 
being sensed by the element thermostat.

The Tank anode is a long Zinc rod that runs horizontally up the centre 
of the inner tank that contains the HOT water.
It has a large 32mm ish Flat head Hex Bolt shape on the end where it 
screws into the steel tank.
To get to this you need to remove the plastic plate on the end of the 
tank with the electricity and water supply/outlet pipes.

DON'T FORGET TO ISOLATE THE ELECTRICITY before removing this cover as 
there are exposed power connections under the cover.  The outside of the 
tank and anode should be earthed back via the electricity connections.

I use a bit of foam pipe insulation cable tied around the Anode head to 
hold a DS18B20 firmly against the Anode Head.
You can buy a waterproof DS18B20 connected to a cable stub
or in my case I buy the DS18B20s for less than $7 & make my own 
waterproof end.
When I prepare each DS18B20 for deployment I solder a shielded cable to 
the 3 pins Vdd (5V), Data, Ground (shield) 
and then enclose the end of the cable and pins in 5 minute araldite 
epoxy making thin layer over the sensor body complete but fairly thin so 
there is not too much thermal insulation.

The other useful location I suggest is on the hot water pipe leading out 
of the tank, but away from the tank, as this can show you and the 
software with the top tank temperature of the drawn water and timing of 
water usage information, that could assist you predicting a schedule of 
when to boost the tank to be ready for normal usage.

Cheers Neil VK1NP

On 12/11/2015 6:36 AM, Paul Wilson wrote:
> Looks like just the thing I'm looking for,  the details I'm wanting is 
> details of the sensor connection with the hot water tank.
> Where do you place sensor to get most accurate temperature reading?
> My model is a 300j.
> Thanks for the info.
> Paul
> On 11/11/2015 10:21 PM, "Neil Pickford" <neilp at goldweb.com.au 
> <mailto:neilp at goldweb.com.au>> wrote:
>     Hi Paul
>     I am monitoring a Solahart system (have been for about 6 years)
>     using Linux, One wire sensors, OWFS, Cron, RRDtool & Shell
>     Scripts.  The One wire interface into Linux machine is via a
>     standard RS232 serial port from a Onewire converter or master hub.
>     See <http://happy.emu.id.au:8430/>
>     I am using Dallas One Wire DS18B20 temperature sensors,
>     One wire counters (wind & rain [future water/gas]), and
>     a One Wire A/D converter card (wind direction).  The A/D board has
>     inputs & outputs on it too that could control your contractor.
>     Most of the One wire infrastructure (Master Hub, Counters, A/D
>     converter, Relay board) is available from Hobby Boards.
>     <http://www.hobby-boards.com/>
>     My system is just monitoring and pretty agricultural in the shells
>     scripting, However if you can figure out how to process numbers in
>     shell or another language you could easily program some automation
>     of the Bypass relay.
>     Happy to share scripting and system setup info.
>     The location to place your key temperature sensors is:
>     a) on the anode of the Solahart tank. (Mid tank temp)
>     <http://happy.emu.id.au:8430/temps/Last_Week_tankanode.png>
>     b) on the hot water pipe feeding your house (mine is at the inlet
>     to the solar tempering valve).
>     This gives a good indication when hot water is being used. See
>     spikey brown curve.
>     <http://happy.emu.id.au:8430/temps/Last_24_Hours_roofspacehw.png>
>     Or you can look at all the temperatures together :)
>     <http://happy.emu.id.au:8430/temps/Last_2_Days_temps.png>
>     There is a thread on CLUG about this in Feb/March 2010 " [clug]
>     Linux compatible external Thermometer via OWFS"
>     Cheers Neil VK1NP.
>     On 11/11/2015 5:56 PM, Paul wrote:
>         I've done a bit of research but just an update on my Home
>         automation project.
>         I spoke to SolarHart about my booster switch and looks feasible.
>         I need to get a relay (contactor) installed on the booster
>         circuit and then I can put a automation switch to control that.
>         So now just need to check out Linux Home automation s/w thats
>         compatible with the modules and scripting I want to use..
>         Paul
>         On 05-Nov-15 1:13 PM, Paul Wilson wrote:
>             John,
>               I don't have a Off-Peak meter, but would be an
>             interesting excercise to figure out if
>             its better to leave booster on vs switching on 1-2 hours
>             prior.
>             Also I would like a bit more remote control than a basic
>             timer, ie for Winter I probably
>             would need to adjust it vs' summer.
>             Ideally I would like to monitor my tanks temp but I don't
>             know how to do this .
>             Paul
>             On Thu, Nov 5, 2015 at 10:17 AM, Bryan Kilgallin
>             <bryan at netspeed.com.au <mailto:bryan at netspeed.com.au>
>             <mailto:bryan at netspeed.com.au
>             <mailto:bryan at netspeed.com.au>>> wrote:
>                 Paul:
>                     The project I'm wanting to get started on.. Is to
>             automate my  solar hot
>                     water booster. I currently have to manually switch
>             this on if we get a
>                     couple of days of cloudy days.
>                 I look at weather forecast. For example Zehr-enhanced
>             infrared satellite view. I think
>                 that will be more useful.
>                 --
>             www.netspeed.com.au/bryan/
>             <http://www.netspeed.com.au/bryan/>
>             <http://www.netspeed.com.au/bryan/>
>                 ==========================
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