Temp overshoot/lag with ezboil

[Goowa]

Ran my system last night and everything went really well, but I overshot my strike temp by roughly seven degrees. I've got a Thermowell run through the side of my kettle, and it's at the same height as my element and between the drain and the element. Photo attached.

I've got a four inch probe screwed into that Thermowell. I don't have any grease in there. I'm not circulating while heating the strike water. And finally I'm running the DSPR320 ezboil.

Anyone have experience like this with that controller? Could it be caused by an air gap between the Thermowell and the probe?

 

[BeardedBrews]

It could be an air gap issue if you put a thermometer in the water and it reads different than your temp probe.

As a quick test you could take the probe out of the Thermowell and put it directly in the water. If that fixes it you've found your problem.

The other thing that could cause small problem is not mixing the water while heating.

 

[don_bran321]

My EZ boil is spot on. Never had an overshoot.
Most probes suggest direct contact for best results

 

[processhead]

If you determine that an air gap between the thermowell and the probe is your problem, try filling the well with mineral oil. Then use teflon tape to seal the threads of the probe in the well. Repeat your wet test and see if the problem reoccurs.

 

[Goowa]

If you determine that an air gap between the thermowell and the probe is your problem, try filling the well with mineral oil. Then use teflon tape to seal the threads of the probe in the well. Repeat your wet test and see if the problem reoccurs.

I read a few places that desitin cream works really well. I am concerned however about the maximum temperature for that cream. Has anyone ever used that in a boil kettle? Most places I read cited it for use in a fermenter Thermowell.

 

[augiedoggy]

why not use thermal grease? thats what its for... syringe of it is cheap on ebay or amazon. if it were me id replace the whole thermowell with a pt100 threaded right through the kettle wall like most do. otherwise you will always have some delay and slight overshoot.

 

[Goowa]

why not use thermal grease? thats what its for... syringe of it is cheap on ebay or amazon.

I tried the desitin cream and it wasn't a problem operating at that temperature. The probe was really slow to react both in the Thermowell with the cream and directly in the water. I think I need to get a new probe, maybe I'll go inline with the recirculation. I bought a T fitting just in case I needed to go that route.

Ideally I would like the probe in both locations. One for recirculation and one for kettle temps. That said, wouldn't it suffice to measure chilling temp inline as I run it out to the chiller? If the temp out of the kettle is 160, I can stop chilling and do hop stands. Amirite?

 

[processhead]

I tried the desitin cream and it wasn't a problem operating at that temperature. The probe was really slow to react both in the Thermowell with the cream and directly in the water. I think I need to get a new probe, maybe I'll go inline with the recirculation. I bought a T fitting just in case I needed to go that route.

Ideally I would like the probe in both locations. One for recirculation and one for kettle temps. That said, wouldn't it suffice to measure chilling temp inline as I run it out to the chiller? If the temp out of the kettle is 160, I can stop chilling and do hop stands. Amirite?

While anything is possible, delayed temperature response time would be an uncommon failure mode for a probe used outside a thermowell.

Many PID's and other display devices that connect to temp probes have software settings that condition the input signal from devices like a temp probe. Before replacing the probe, you may want to make sure your controller isn't set up with an extended filter delay on the temperature input.

 

[golfindia]

Without recirculating, the temp at the probe in a big pot of liquid is going to lag. Prove (or disprove) by stirring it up after the liquid has reached set point.

I always heat strike water with recirculating pump off (noise), then turn on the pump and let it equalize again right before I use the water.

 

[BeardedBrews]

I went from inline to kettle mounted because I found times where I wanted to measure temp without pumping. Similarly, if you have a pump failure during the brew day you're not dead in the water.

If you're applying heat, from a control standpoint you want the temp probe to be close to the heat source. That way you don't over shoot in the zone right around the heat source. If you find that the temperature at the element and probe zone is different from everywhere else in the kettle then that simply means you aren't mixing well enough.

If the probe is far from the element you could heat the liquid near the element faster than the probe can see, causing an overshot once everything starts mixing evenly.

 

[JONNYROTTEN]

I was overshooting my temps with my PID. Not an easy boil but same idea.

I started killing the power to the element for the mash. Temps only drop a couple deg in an hour and they say most conversion is done in 10 minutes. I havent noticed any difference in the beer and I dont have to babysit the mash. Half the time I run out of the house and errands while I'm mashing....no power...no worries

Last batch I went to the gym and came back and started the boil...easy brew days

 

[Goowa]

I went from inline to kettle mounted because I found times where I wanted to measure temp without pumping. Similarly, if you have a pump failure during the brew day you're not dead in the water.

If you're applying heat, from a control standpoint you want the temp probe to be close to the heat source. That way you don't over shoot in the zone right around the heat source. If you find that the temperature at the element and probe zone is different from everywhere else in the kettle then that simply means you aren't mixing well enough.

If the probe is far from the element you could heat the liquid near the element faster than the probe can see, causing an overshot once everything starts mixing evenly.

My probe is equidistant from the element and the drain, directly between them, and at the same height in the kettle. I think I'm ok with placement. Also, while heating the strike water I was running the pump and whirlpooling the water around in the kettle clockwise. That forces the water current to go over the element, over the the probe, and then out the drain, pump, whirlpool fitting, repeat.

Any issues with that method? Or should I just stir the water periodically. Am I cooling the water slightly by sending it through the pump and lines?

 

[BeardedBrews]

My probe is equidistant from the element and the drain, directly between them, and at the same height in the kettle. I think I'm ok with placement. Also, while heating the strike water I was running the pump and whirlpooling the water around in the kettle clockwise. That forces the water current to go over the element, over the the probe, and then out the drain, pump, whirlpool fitting, repeat.

Any issues with that method? Or should I just stir the water periodically. Am I cooling the water slightly by sending it through the pump and lines?

That seems like the ideal approach to me.

If you are experiencing an overshoot with this setup then the fix is an easy adjustment in the controller. OSCR will remove your overshoot and is pretty close to 1-1 in my experience. 5F overshoot = set oSCr to positive 5 and you should be golden

 

[golfindia]

Original post said:

"I'm not circulating while heating the strike water."

Now :

"Also, while heating the strike water I was running the pump and whirlpooling the water around in the kettle clockwise."

 

[Goowa]

Original post said:

"I'm not circulating while heating the strike water."

Now :

"Also, while heating the strike water I was running the pump and whirlpooling the water around in the kettle clockwise."

Yea sorry if I wasn't clear, that was my wet test, I did an actual brew last night and circulated during that on suggestions that the water needs to be stirred.

 

[Bobby_M]

There is no reason to use a well since there are plenty of small diameter liquid tight probes availabe that read quickly. In the meantime, bump up the controller OSCr setting a few points. It will help.

 

[don_bran321]

Also went from inline to kettle mounted because there was so much fluctuation and if you were not pumping
IT would not read the tempurature way off.
Never looked back.

 

[Goowa]

Also went from inline to kettle mounted because there was so much fluctuation and if you were not pumping
IT would not read the tempurature way off.
Never looked back.

I ended up buying the weldless probe from the electric brewery, and nailed my strike temp on the first go. That seems pretty definitive that it was the well insulating my old probe.