RANCO ETC's - NOT sensitive enough?

Tue May 26, 2009 7:39 am

I've noticed in side-by-side comparisons with digital thermometers, my Ranco etc is very slow to react to finding the actual temp--even when placed directly in liquid. Anyone find this to be true?

It gets even worse when the thing is inserted in a thermowell--it just doesn't pic up the right temp fast enough--it's routinely 5-10 degrees off of what is really going on, indicated by reliable digital thermometers placed in the same location

For instance: I set my ranco to 152 degrees, 1 degree differential, and to "heat." I then start circulating my mash liquid through it @ 152 degrees--understandably, the temp will drop a bit when it first travels through my heat exchanger and then back to my return manifold--but after awhile, the temp display on the ranco should "catch up" right? But it doesn't

so this is what I get: I have the controller set to 152, while the probe sees 145 liquid running past it. My other digital thermometers tell me however, that the liquid running past the probe is really 152. So the Ranco is 7 degrees off. Because the ranco "sees" 145 and the setpoint is 152, it's going to keep increasing the heat in order to get it to 152. But because it's 7 degrees off, when the probe sees 152, the mash has been heated to 159! So obviously, it's not accurate, which is a huge problem.

This is my second Ranco - I returned the first one. Perhaps there isn't enough heat being conducted around the probe? I am affraid to submerge the probe in the mash liquid itself, because I hear the probes can go bad, so I purposely put it in the manufacture's copper thermowell. Not good enough.

Anyone else have temp problems with their RANco's or know of how I can correct this?
Kazi the Younger
 
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Re: RANCO ETC's - NOT sensitive enough?

Tue May 26, 2009 8:16 am

I use Rancos/Johnsons for fermentation control, but trust my mashing to the Loves.
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Re: RANCO ETC's - NOT sensitive enough?

Wed May 27, 2009 7:00 am

how do you wire one of those up with a single probe and a single heating element? any info on your site?
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Re: RANCO ETC's - NOT sensitive enough?

Wed May 27, 2009 7:43 am

Kazi the Younger wrote:how do you wire one of those up with a single probe and a single heating element? any info on your site?

"Those" what? The Loves?

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Re: RANCO ETC's - NOT sensitive enough?

Wed May 27, 2009 8:21 am

awesome...thanks!
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Re: RANCO ETC's - NOT sensitive enough?

Wed May 27, 2009 12:19 pm

I'm using Ranco's for my HERMS and my heat/cool fermentation chambers without any issues.

The Ranco's appear to be really accurate, but they do respond slow.

I think the Ranco's may be purposely damped to filter out quick changes in temp to avoid cycling you heating elements.

I'm trying to understand why the response time is an issue for your setup. I have a HERMS with a water heater element controlled by the Ranco. The water heater element is in a 10 qt pot, filled with water, and a copper coil is submerged in it. Wort is pumped from the mash tun, thru the coil, then back into the mashtun. My temperature probe is right where the wort is returned to the mash. My pump runs continuously. I have no response issues because the heating element cannot change the temp of the heat exchanger water that quickly. The response time has zero effect.

I'm guessing that you are using the Ranco to turn on your pump.
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Re: RANCO ETC's - NOT sensitive enough?

Tue Jun 09, 2009 1:00 pm

I think I found the culprit--it was the the probe not inserted fully in the stream of liquid. I did it this way, and both probe and thermometer are right on. Probe is a little slow to respond, but I guess it's like you said--their should be some insulating there so it doesn't shut on/off so quick.
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Re: RANCO ETC's - NOT sensitive enough?

Tue Jun 09, 2009 1:52 pm

Kazi the Younger wrote:the probe not inserted fully in the stream of liquid

Tsk, tsk, tsk...

INSERT YOUR PROBE LIKE YOU MEAN IT
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