12V Digital LCD Thermostat Temperature Controller
 

http://i1188.photobucket.com/albums/...1_conew2-2.jpg

12V Digital LCD Thermostat Temperature Regulator Controller Aquarium fish Blue D | eBay


www.willhi.com/Documents/WH7016Cdatasheet.pdf

I wondered about these little controllers.. Then I read the pdf..
These things are nice units.. Programmable heating or cooling modes,
hysteresis (1 to 15 C) adjustment, Delay time 1 to 10 minutes for your compressor,
and temperature calibration of the thermistor! :D

I kinda like the 12V model, but they also make them to run off 240 or 120 AC.
Digital Temperature Controller Thermostat Aquarium °F | eBay

I was thinking about buying a 12VDC unit for my ASHP-DHW project.
Since I will likely use an SSR and SSRs need a DC control signal.

Maybe use something like this,
Temperature Switch N.C,Bimetal disc thermostat,KSD301 N/C 50 °C.10pcs | eBay
for a high temperature limit turn-off switch.

Comments please:

Thanks..

Sounds like a good idea to me. What do they use for temperature sensors? The datasheet for some reason wouldn't load for me.

The terminal is marked NTC. I assume it's a Negative-Temperature-Coefficient Thermistor..

Here's a cut-n-paste from the pdf..

Electrical performance: ③
Temperature measurement range: -50 ~ 110 ℃℃
Temperature control range: -50 ~ 110 ℃℃
Temperature measurement error: ± 0.5 ℃
Sensor Type: NTC (10K/3435)
Control accuracy: 1 ℃
Working voltage: AC/DC12V
Working current: <2W
Relay contact point current: AC 7A/220V
Data storage : Yes
Working temperature: 0 ~ 50 ℃℃
Storage temperature: -10 ~ 60 ℃℃

Are you saying that you're going for both a digital temperature controller AND a snap switch?

Probably not such a bad idea...

-AC_Hacker

I have not done a lot of brainstorming about the controls,
but I'm thinking that I might want the circulator pump to run,
only when the storage water is cooler than the HX,
And when the HX & the boiler temperatures are equal, the pump takes a break.
Thus giving the HX a chance to heat up a bit more, before the pump comes back on..

I think this function might be filled using my old C30 Solar HW controller.
http://i46.photobucket.com/albums/f147/Xringer/HWC.jpg


Whereas the compressor would be controlled by a new digital controller,
with it's temperature sensor embedded about half way up the boiler.
It would allow me to tweak the max water temp,
to best meet demand with the current weather conditions/basement temp.

I really like the features of the digital controller. Heating or cooling mode,
hysteresis (1 to 15 C) , 1 to 10 minute compressor time delay..
Seems like the idea compressor controller.. & not too expensive. :D

~~~:confused:

I'm not sure if I really want to go this route, because I'm thinking that a CAI board,
with a few temperature inputs and a couple of SSR outputs,
might be a much more flexible solution. Just a bit more complicated..

After ordering the A7 ASHP, my total 'free' Ebay bucks covered the cost of this toy..
Just wanted one to play around with.. :)

I decided to get the 110v model.. 110V Digital LCD Thermostat Temperature Regulator Controller Aquarium Fish Tank | eBay

The price isn't bad, but the shipping takes forever!!

Well, not quite forever.. :)

http://i46.photobucket.com/albums/f1...t/P1000675.jpg

It's a very compact unit. Feels solid, like good quality. Now I need to find a smallish AC cord for it.

Hi,
does it remember the settings after power outage?
THX

Yeah, it seems to be working that way. It's got NV ram for the settings.
There is a jumper terminal on the back that will disable SET function.
It keeps anyone from changing your settings.
Just install the jumper After you make all your settings.. :)

I'm just using this 120vac unit to monitor the temperature (in C) of my new water heater.

Then today, I saw this PID unit.. Smart Digital PID Temperature Control Controller Furnace Kiln Power AC 85V-260V | eBay

http://usih.merchantrunglobal.com/Im...ListingID=2681

Comes with a sensor too! Seems like a compact unit.
Best part, does C & F !!