Electrically control temperature

jimbo480 · Feb 22, 2016

Hello, I have just joined this forum.

I am making a tank that has to keep a liquid solution at a specific temperature. I am trying to figure out a way to do this. My plan was to use the element of an immersion heater and remove the thermostat from it. I have been looking at temperature controllers online but honestly have no clue about them. Is it possible to wire the following item into the immersion heater element and achieve this?

REX-C100 Digital PID Temperature Control + 40A SSR + K Thermocouple + Heat Sink | eBay

Will it be able to monitor the temperature and turn the element on/off accordingly to keep the solution at a temperature i have set? If not, is there another way?

Thanks

Darkwood · Feb 22, 2016

Welcome to the forum

Lucien Nunes · Feb 22, 2016

That controller kit does look pretty suitable for the job, although at that price it is difficult to be totally certain of the build quality. I don't know what temperature you want to achieve but so long as it's no higher than the maximum setting of the the immersion heater's internal thermostat, leave the thermostat in situ as an emergency backup anti-boil protection, and it won't interfere with the operation at all.

jimbo480 · Feb 22, 2016

Good man Lucien. The temperature that needs to be achieved will vary from approximately 70-90 degrees celsius. It is my understanding that an immersion heater heats water up to near boiling point and then the thermostat cuts it off so for this reason I thought the element would be fit for purpose. Am I correct?

Also I am assuming that the element is connected to the controller, and the controller is wired directly into mains power(I was thinking of using 32A supply since immersion heaters draw quite a bit of electricity). Is this correct or is there something I have overlooked.

Thanks very much you have been a good help, my electrical knowledge is limited as you have probably guessed.

Marvo · Feb 23, 2016

What exactly is the liquid solution that you're heating? Is the liquid just sitting in the tank or is there flow through the tank with cool liquid entering?

The element in an immersion heater is designed to heat water. The element has a given kilowatt output and the tube has a certain surface area, from this the element has a certain heat density. Different liquids have different viscosities and specific heat capacities and there's a limit to the heat density of the element you can use with different liquids so the immersion heater element might not be suitable for other liquids. Also different liquids absorb heat at different rates so depending on the liquid the element can overheat and damage the incoloy/hastelloy/copper tube.

davesparks · Feb 23, 2016

jimbo480 said:
Good man Lucien. The temperature that needs to be achieved will vary from approximately 70-90 degrees celsius. It is my understanding that an immersion heater heats water up to near boiling point and then the thermostat cuts it off so for this reason I thought the element would be fit for purpose. Am I correct?

Also I am assuming that the element is connected to the controller, and the controller is wired directly into mains power(I was thinking of using 32A supply since immersion heaters draw quite a bit of electricity). Is this correct or is there something I have overlooked.

Thanks very much you have been a good help, my electrical knowledge is limited as you have probably guessed.

An immersion heater normally heats water to 55/60C and the safety cutout is going to be around the 80C mark