Another question about boiling with a PID

[TGnB]

Thank you for your advice in my previous post about SSRs. I started a a new thread because that one seemed to take a different direction. I swapped out my relay and its working great now.

I cannot seem to maintain a boil with my PID. The duration it keeps the element on is just too long to avoid a boilover and I have to turn it off my manual switch


What do you folks do to maintain a boil?

 

[BrunDog]

You need to have your duty cycle high to bring the liquid up to boil temp, then drop it dramatically to maintain it.

For example, I have my duty at 100% until 210 degrees, then it is dropped to 65%. This is automated on my 15 gal, 5500W system via BCS, but there is no reason you cannot do this manually. I would transition a few degrees earlier, like 208. I also recommend fermcap - cheap insurance to prevent or reduce boilovers.

 

[TGnB]

Which setting is duty cycle? I have the Inkbird PID

 

[JONNYROTTEN]

When you first reach boiling hit the manual button.It will most likey say 100.(100% power going to element) drop it to around 75%. For a rolling boil.

 

[FuzzeWuzze]

Also make sure that you check what your duty time is...you should probably use 2-3 seconds. If you have it too long when you lower your duty Cycle its going to pulse from boiling to dead over and over.

Think of duty time as how long a whole cycle to the PID. If its at say 10, and you have your Duty cycle set to 100%, its on 10 seconds, off 0. If you set it to 50% duty cycle its on 5 seconds, off 5 seconds.

This is why most people use low Duty cycles like 2 seconds. At 50% your off 1 second, on 1 second. You'll still see some "pulsing" of the boil but it shouldnt be crazy. Once you have the time set to 2 seconds set it to 100% to get to boil and lower it down to say 70% and wait a minute or two and see how the boil looks and then increase/decrease it 10% at a time until you get your boil where you want. Keep in mind it may get more vigorous as you boil off and theres less wort to heat.

Im not familiar with Inkbird PID's so cant give you specifics about how to set it though.