temperature controll

Hi I know nothing about arduino but someone may be able to point me in the right direction I have asked this question before but am not any wiser.

What I want to do is controll a pump to circulate water through a solar water heating system. I want if collector temp is greater than storage run pump if collector is cooler stop pump I am sure it should be quite simple but likeI say I know nothing about arduino.

I haven't done any programming for years and that was with rudimentary equipment in the 80's and would need to interface with a switching device.Could any one point me in the right direction to read up and learn how to do it and find the equipment I need.

Thanks Jim

I would recommend starting with an Arduino Uno kit. Get to know the programming environment (IDE) and how to breadboard different sensors, switches, LEDs, etc.

Then, we can talk about your project.

Actually, by then you should be able to figure it out on your own; you've described a pretty simple project.

Are you contemplating building such a water heater, or is this a commercial device installed properly and working properly?


There are examples in the IDE to walk you through some of the basics. Water temperature can be measured with a DS18B20 easily. The ones with wires can be had with 1 meter, 2 meter or 3 meter wires

Control a relay module is as simple as lighting an LED.

The relay controls the water pump power so you keep everything in the 5v range.

The relay will require a separate power supply as it has a large surge (for an Arduino)

Put the temperature sensor at the highest point so it will see the heat without water movement.

Consider running the pump for a bit, 2 minutes or some such, then move liquid through the piping. Measure if the water is warm enough to keep pumping.

This is beginners level so a great first project.

add hysteresys to the contol

if pump is not running if water is over 150 turn on relay

if water is under 120 turn off relay

watch the temperatures if you get a drop as the hot and cold mix, you would want to run a simple timer to allow them to adjust.

so, a NANO 3 or more DS18B20 with wires as you need a 5volt relay module (or a couple as they are cheap) 2 phone chargers an enclosure with a clear lid.

I suggest you also get an OLED .96 or 1.3... just one color, but the I2C version as they are so easy to connect.

Hi dave-in-nj With regards to temp controll my temps are not fixed I can buy off shelf a controller to work between set temps.

The system works thus as the collector heats up when its temp is greater then storage, pump on, when temp in storage is equal pump stops, if the storage drops below collector eg another system cools the stored water, pump restarts.The system works purely on the temperature differential.

I am building a greenhouse heating system collector will be poly pipe in an enclosure and an insulated tank it will be run on 12 volts via solar panel "I love something for nothing" eg the sun.

I live in New Zealand in a temperate / cool climate zone on a hobby farm and all the parts are left overs from previouse projects I have had many plants killed by the odd frosts and as I spend time away regularly in a motorhome irrigation would be automatic the system would be backed up with a mains power system if the sun does't shine.

love homegrown vedge.

P.S Hope I am posting my reply in a correct manner, how do I post a reply to a reply to individual post?


From one hobby gardener to another…
Love the fresh tomatoes, cucumber, basil, peppers and ginger.

What you ask is mainstream for an Arduino.
You need a temperature sensor for each thing.
A relay for each motor

sounds like you want :

diffTemp = collectorTemp - storageTemp

If diffTemp >= 5
Run pump

If diffTemp <=0
Stop pump

You get to make it as Smart as you like

greenhouse with windows can also open windows, or close them
start a fan, or shut it off.

ps: yes reply on this thread. keep it on the forum for others to comment, correct mistakes and possibly learn.

your comment about ‘leftover parts’
Any Arduino can read temperature and control a couple of relays.
So, what is in the bin that can be used for this project ?