Boil pot probe question

[Arbe0]

I just put together an electric brew system with a HERMS coil and using PID's for the HLT and Boil pot. In my HERMS pot the temperature probe is in an NPT female T fitting. My first test was just a water test. First I ran water in the pot and brought it up to temperature, I then realized I wanted to recirculate the water in the pot. when I did this I noticed the temperature went from 168 F to 180 F.
This told me I should always recirculate in order to get my correct temperature.
I still haven't put the temperature probe into the boil pot and the question I have is about where is the best place you put your temperature probe in the Boil pot, I have seen them attached to the pot and also in the T fitting. also do I need to recirculate it to get a good boil without the electric element coming on then off all the time.

 

[kh54s10]

Why do you need a temperature probe in the boil kettle? You just need to control the amount of power so that you get a nice slightly rolling boil. Some controllers allow you to dial in the percentage of power going to the element.

The only reason I could see to monitor the temperature at all is when cooling.

 

[sicktght311]

I've had my temp probe in the side of the boil kettle running it that way for 6 months now without a single issue. While heating up to a boil, theres really no need to be super accurate, and once you start getting over 200 degrees the water starts moving around so its doing its own recirculation.

Typically you set your PID to manual mode for boil and set the power to 100% until you reach boil, then reduce it to whatever percentage of power maintains that level of boil. It varies depending on your system and your element wattage. I run 120v 1650watt element so i leave the pot covered and run at 100% until it reaches 212, then i crack the lid about 1-2" and leave it at 100% to maintain a good rolling boil.

 

[Spartan1979]

Why do you need a temperature probe in the boil kettle? You just need to control the amount of power so that you get a nice slightly rolling boil. Some controllers allow you to dial in the percentage of power going to the element.

The only reason I could see to monitor the temperature at all is when cooling.

With my system, a probe in the boil kettle allows me to set a temp lower in the boiling point so it doesn't start to boil if I'm not paying attention. I'm also using a steam condenser so I have a lid on and can't see the boil. The probe tells me if I'm at boiling or not if I'm trying to adjust it (it's a new system so I'm still dialing it in). And, as you mentioned, I use it to monitor the temp while I'm chilling.

 

[kh54s10]

With my system, a probe in the boil kettle allows me to set a temp lower in the boiling point so it doesn't start to boil if I'm not paying attention. I'm also using a steam condenser so I have a lid on and can't see the boil. The probe tells me if I'm at boiling or not if I'm trying to adjust it (it's a new system so I'm still dialing it in). And, as you mentioned, I use it to monitor the temp while I'm chilling.

It makes very good sense if you are using a condenser. And I guess it could help if you set it to limit the temperature when approaching a boil. But don't get too distracted or your wort will never boil.

 

[sicktght311]

I also like having it in the side for chilling purposes. I use an immersion chiller and whirlpool the wort during chilling with my pump to not only speed the chilling process, but also to move the wort around to get an accurate temp reading to make sure i'm down to pitching temps. Without moving the wort around, a probe in the side of the kettle wouldnt be very accurate with the amount of temperature stratification with an immersion chiller

 

[Arbe0]

I did a water test with the probe out of the boil pot, (just hanging out I the air). I used the manual mode and at first put it on 100% to get it started, then turned it down to 50%. No matter where I put the Percentage the element would turn on then off then on. It wasn't a good rolling boil, it would boil then shut off and boil again about every 3 to 4 seconds.
When I did a boil water test in the HLT with the probe attached to the "T" fitting and I recirculated the boil was constant and a nice rolling boil.
Do I need to look at the PID settings to fix the on and off that occurred with the boil pot? Using an Auber SWA 2451 PID

 

[sicktght311]

Edit - never mind

 

[BeardedBrews]

I did a water test with the probe out of the boil pot, (just hanging out I the air). I used the manual mode and at first put it on 100% to get it started, then turned it down to 50%. No matter where I put the Percentage the element would turn on then off then on. It wasn't a good rolling boil, it would boil then shut off and boil again about every 3 to 4 seconds.
When I did a boil water test in the HLT with the probe attached to the "T" fitting and I recirculated the boil was constant and a nice rolling boil.
Do I need to look at the PID settings to fix the on and off that occurred with the boil pot? Using an Auber SWA 2451 PID

https://www.auberins.com/images/Manual/SWA-24x1 v1.pdf

See page 3 and section 4.4

Adjusting T will change the duration of on-off power cycling. A setting of 2 is recommended for SSR which would be 1.2 sec of full power and 0.8 seconds of no power when running at 60%

 

[Arbe0]

In my setup notes I had "T" to be set at 2, but when I checked it just now it was set at 10. Thank you for hopefully finding my problem. I will test it tomorrow to make sure, but I am sure you are right BeardedBrews. Thank you again.

 

[Arbe0]

Did a water test with the PID "T" setting at "2" today I started with 100% and when it started to boil I dropped it down to 50% it worked perfect. The boil went good like is supposed to. This shows that the temperature probe doesn't need to be in the pot at all. I have it just attached to the controller on one end and a temperature probe attached to the other end, not in the pot at all just rolled up and hanging in the air close to the controller. The PID is on the manual setting other wise this won't work. If I wanted the PID to measure the temperatures and have the timer work with it I would need to put the probe into the pot, but I just don't need to do that. When it comes to a boil I use my old timer, that just seems easier for me.
My problem was not paying attention to the manual and the settings that I used to program the PID. Thank you Beardedbrews and everyone else for putting me on the right path.