Home Radiator Balancer

This is just a little tool I thought may be useful for balancing your Home Radiators.

• I know we have infrared temperature sensors guns, but I thought it may be a nice Arduino thing to try.

This Instructable is not about pluming, installing or bleeding Radiators.

• I assume all that is done.

This Instructable is about making a tool to Balance or check the Balance of your installed Home Radiators.

• This tool is quite simple to make.
• It could be temporary if you have an Arduino kit and just want to check your radiators.
• You could make it into a permanent tool if you are a plumber that installs Home Radiators.

It is based on an Arduino Nano

• Has 2 Temperature sensors.
• Has an LCD to display the state of the radiator.

I assume you have some knowledge of the Arduino Architecture.

• Arduino has a great support for there system.
• There are many professional tutorials.

I have kept this to a minimum, you may only need to build this for a one time use.

• If you are a plumber you make want to make a box for it.

Required parts are:

• Arduino Nano. An UNO can be used. If you look on eBay take care which chip is on the board. (I don't think many ATmega328 left)
• An optional board to mount the Arduino Nano.
• An Optional PLA 3D Printed Mount for Arduino Nano and LCD.
• One 1602 Display with an I2C Interface. (PCF8575 Adapter)
• Two Temperature sensors, DALLAS DS18B20 Digital Thermometer (TO-92 package). Or equivalent (Mine are RW1820).
• One Resistor 4.7k.
• A good length of 3 core cable. The cable I have used on this is light weight servo cable 32 SWG. The cable needs to reach each sensor attached to each end of the radiator, if you have long radiators you need long cable.
• Some Cable Shrink Wrap, I have used 3mm unshrunk.
• Some Colour marker. I use coloured Nail Varnish. (Red and Blue)
• Small double sided Velcro Straps. To hold sensors on the pipes,

Balancing radiators is done by adjusting the Lock Valves on each Radiator so that all the Radiators worm up and heat at the same time.

• If you have 6 Radiators in your house, 4 of them warm up quickly and the other 2 take ages to warm up, then the radiators need balancing.
• By adjusting the Lock Valves on each Radiator makes sure that the Hot Water from your Boiler is distributed correctly to each Radiator.

When should Home Radiators be Balanced.

• After Installation.
• If a Home radiator has been added to the system.
• If a Home radiator has been removed from a system.
• If a Home radiator has been changed.
• If the boiler has been replaced.

Normally when a system has been set up correctly it should not need altering.

• A well balanced system will be more economical.
• A Home Radiator should have a Temperature Differential of 11 to 12 degrees Celsius.
• A Temperature Differential = The difference between the Temperature of the Inlet and Outlet pipes.

Home Radiators will have two valve attached to them. One on the inlet and one on the outlet.

Lock Valve

• The Lock Valve is usually on the outlet side of the radiator. (it may not)
• This valve regulates the Flow of water From your Boiler into the Radiator.
• This valve is usually set when the system is installed.
• This valve usually has no easy means of adjustment, this is to prevent accidental adjustment.
• This valve should only need adjusting if there has been a change to the heating system.
• The Lock usually has a cover, if you remove the cover, only the spindle of the valve will be seen. There will be nothing attached to it, so you unable to alter it.

The other Valve

• The other Valve is for adjusting how Hot the Radiator gets.
• This valve could be of any type.
• The valve could be a simple valve that can be manually adjusted with a handle on the top.
• The valve could be linked to a Room Temperature Control System.
• The valve could have it's own type of Temperature control.

To simplify.

• The Lock Vale controls the Water Flow. (Adjusted on installation or change to the system)
• The Other Valve controls the Heat. (Adjusted to you preference when ever you like)

My tool has 2 Temperature sensors.

• One sensor is attached to the Inlet pipe. (One marked for Inlet)
• One sensor is attached to the Outlet pipe. (One marked for Outlet)
• I use double sided Velcro straps to hold the sensors in place.

The Arduino Nano gets the temperature readings from each sensor.

• The Arduino calculates the Differential Temperature between the two sensors.
• If the Differential Temperature is Low, it will display on the LCD that the Valve needs Opening.
• If the Differential Temperature is High, it will display on the LCD that the Valve needs Closing.

The LCD also displays the Temperatures.

• It displays the Differential Temperature so you can see how close you are in your adjustments.

The Target Differential Temperature is set in the code for the Arduino.

I thought I would do the Circuit and Code with Tinkercad for this Instructable.

• Didn't have much look Emulating though.
• I thought I was in luck when I found Temperature Sensors and I2C LCD.
• Fell short when it came to the OneWire Library.

I have also done a Fritzing.

• Files are attached.
• Code needs to go in folder with same name without ".ino".

The cable are quite simple. Both cables attach to the same pins on the Arduino.

• The cables need to be of a length that will reach both ends of the Radiators you are going to check.

We have two long cables attach a sensor to end of each cable. The cable I am using is 3 ply Brown, Red and Orange.

• I am wiring them using all three wires.
• Brown = GND
• Red = VDD
• Orange = DQ (Will be pin 8 on the Arduino)

I have used Shrink Wrap to cover the soldered joints.

Each Sensor needs identifying. One will be used for the Pipe IN and one used for the Pipe OUT.

• To be sure that the correct sensor is used for each pipe I have colour coded them.
• The one for the IN Pipe I have marked Red.
• The one for the OUT Pipe I have marked Blue.
• Does not matter which is which at this time. We will sort this in the code.

I am using an Arduino Nano Break Out Board to mount my Arduino Nano so the other ends of the cables can be fitted to a single 3 pin DuPont connector.

• The sensors require a 4.7k resistor in the circuit.
• I have fitted the resistor to the terminals of the connector.
• Don't make the wire from the resistor too short like I did :)

Plug the connector into pins for Pin 8 on the Breakout board.

To use these sensors requires two Libraries to be installed in the Arduino IDE. it also requires Libraries for the LCD.

26   #include <Wire.h> 
27   #include <LiquidCrystal_I2C.h>
28   #include <OneWire.h>			//	https://www.pjrc.com/teensy/td_libs_OneWire.html
29   #include <DallasTemperature.h>	//	https://github.com/milesburton/Arduino-Temperature-Control-Library

Wire Library is installed by default.

To install Libraries use the Libraries Manager.

• You can search for the libraries using the search bar at the top.
• be sure to have the correct libraries as shown in the image.

My Code

In my code there are 3 values that may need changing.

46    #define SENSOR_IN					1			//	May need to Swop this value with below.
47    #define SENSOR_OUT				0			//	May need to Swop this value with above.
48   #define TEMPERATURE_DIFFERENTIAL	11.5		//	Change to your prefference.

Lines 46 and 47 values may need swopping.

• After uploading the code, if you find the markings on the sensors are wrong for the pipe they are marked, if so, swap them.
• To find which sensor is which, hold one in you hand to warm it up, the temperature will show on the LCD.

Line 48 is the Differential Temperature, Celsius.

• If you think this should be different, change it. You may want to check your system specifications.
• I think the figure I have set is a general rule of thumb :)

Oh, if you don't want my name on the screen, that's line 76.

76	lcd.print("By Tim Jackson");

The code is attached.

• The code requires placing in a folder of the same name without the ".ino"

Sorry about the title, that pun is stuck in my head ha-ha.

How to balance your radiators

Be carful not to scold yourself.

• Radiators get hot

First Thing

Do your Radiators need balancing?

• It's not a 5 minute thing.
• Q. How long will it take? A. How long is a piece of string?

If they are not to bad, all seem to be working OK,

• Then you may just want to make this tool just for the fun of it and check your radiators.
• If you check them all and they all seam to be the same, then leave well alone.

You may just need one or two tweaking.

If you find things a mess, then you may want to discuss what you have found with a professional plumber.

• If your system is old, It may not be just a balancing problem.
• At least if you check with this tool you will have an idea if any issues are at hand.

You want to dive in the deep end.

Ideally when your Central heating comes on. All your radiators should heat up at the same speed.

• I assume you know how to bleed your radiators and this has been done.

Tools:

• My Radiator Balancer.
• A Lock Valve Key. I find these hard to come by, I find a small adjustable spanner will do, if not that, some good grips.

Before your Central Heating comes on:

• Open full all the Comfort Valves (The ones you can adjust by hand)
• Open full all the Lock Valves.

When you Central Heating turns on from cold:

• Go around the House and note which Radiators get warm first.
• Make a note of the sequence of which heat up first. (Write it down)

You can do the next steps over time or keep turning on and off the Central Heating.

• I think it's best to adjust each radiator from cold.

All valves should be open at this point.

• We start with the radiator that got hot first.
• We then work down your list Hottest to coldest.

For each Radiator.

Before the Central Heating comes on.

• Close the Lock Valve.
• Open the Lock valve a 1/4 of a turn so that some water will pass.
• Attach the sensors of my Radiator Balancer to the correct pipes.

When the Central Heating comes on.

• Check that some Hot Water is getting into the Radiator.
• If no Hot Water is getting into the Radiator, open the Lock valve a little more until some Hot Water is getting into the radiator.
• Leave for a little while. A few minutes. (At cold the readings will be wrong)
• Go back to the Radiator periodically to check the readings on the Radiator Balancer LCD.
• There will be Text saying OPEN or CLOSE.
• Open or Close the Lock Valve a little as the Text says.
• The LCD also shows the Differential Value under this Text. We are trying to get close to what we set in the software, about 11.5.
• After a few adjustments, you should get an idea how far to open or close the Lock Valve each time.
• When the Differential Value is close to what you want, move on to the next Radiator on the list.
• Best to start from cold again.

I have six Radiators. I did one each evening as the Central heating came on.