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Scotsman diagnostics giving me problems again
Hello all, I have a Scotsman CME256. I have personal had the unit for 2 years now and really love it when it works. But every once in a while i will have a minor issue that stops me dead. Currently i have my water diagnostic light on one blink. From the diagnostic chart that tells me the water pump isnt working, only problem being is that it is working fine. The manual doesn't tell anything to test or check in this situation.
From what i understand from reading the manual, during the normal cycle the pump will shut off and look for the water level to rise(im guessing from the water draining back)
5. Measures the reservoir water temperature. If the
machine is operating correctly, the reservoir water
temperature will fall at a standard rate. The
Controller will be checking to see if the water
temperature fall matches that rate.
If not, it re-checks the discharge line temperature.
If too low, it Shuts Down on a Refrigeration Error.
If the discharge temperature is acceptable, the
water system is checked by shutting off the water
pump and determining if the water level goes up
enough. If it does not, it is assumed that there is a
water pump problem and the machine Shuts Down
on a Water Error.
If the water level does measure up" the water
pump is restarted and the controller then
measures how long it takes to lower the water
level. If the water level does not fall, the machine
Shuts Down on a Water Error.
I had a hard time making this machine run at the beginning of the year, i kept getting refrigerant errors . Once i got it running it has been working excellent. Now all of a sudden it wont make a single batch. So something must have failed, but what? The water level sensor?
This machine is annoying how the diagnostics work, everything is passive. Every time i have had the machine shut down because of an error it has been something small and unrelated
Any input would be greatly appreciated
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Those "IDIOT" lights only point us in a direction, they do not tell us what's wrong. The entire "System" need to be checked!
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I did the initial testing development on the CME line back in the 90's. The diagnostics have been updated since I left. We derived the batch weight by how much water is missing via an electronic eye through the float. The logic for the alarm is that if the temp is not dropping it is either a lack of water or a refrigeration issue. If the discharge temp is warm then the pump is shut off which should make the water level rise if there is water. So it sounds like it is not seeing the correct water level and intertrets it as an empty sump. During development I saw the moving water in the sump actually get to about 27 degrees and turn to slush. The machine would continue to run with no water pumping so I had to stop the pumpand let the evap pull down enough so that when the pump turned on it would create a layer of ice that would actually insulate the flowing water from getting too cold and creating slush.
By the way advertising didn't accept my submission. "Fist it was E=MC^2, not it's ICE=CM^3"
Oh, and the bean counters wanted to move the water inlet valve to the back to save on tubing costs but we stopped them.
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Originally Posted by
incontrol
I did the initial testing development on the CME line back in the 90's. The diagnostics have been updated since I left. We derived the batch weight by how much water is missing via an electronic eye through the float. The logic for the alarm is that if the temp is not dropping it is either a lack of water or a refrigeration issue. If the discharge temp is warm then the pump is shut off which should make the water level rise if there is water. So it sounds like it is not seeing the correct water level and intertrets it as an empty sump. During development I saw the moving water in the sump actually get to about 27 degrees and turn to slush. The machine would continue to run with no water pumping so I had to stop the pumpand let the evap pull down enough so that when the pump turned on it would create a layer of ice that would actually insulate the flowing water from getting too cold and creating slush.
By the way advertising didn't accept my submission. "Fist it was E=MC^2, not it's ICE=CM^3"
Oh, and the bean counters wanted to move the water inlet valve to the back to save on tubing costs but we stopped them.
Was never a fan of the CME but great story.
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Originally Posted by
incontrol
I did the initial testing development on the CME line back in the 90's.
Good Stuff "incontrol", Thanks for Sharing!
LZ...
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Thank you incontrol for the info. I have been working 7 days a week and have been too busy to work on this further. Once in a while the machine will run for days and never miss a beat. I have replaced the water level sensor and a couple months ago i replaced the temp probes. i have not had the time to test the probes with a meter to see if they are within spec for the actual temperature. but i dont think that is what is causing my issue at the moment. I have also gotten an occasional refrigeration error.
Saying that my problem are intermittent, and my sensors are new, i found a used new style CME controller that im going to try .
When the machine is running i watch the water level float bouncing around because of the water flow going into the pump. and the float rod only has a single window cut in it. the water level sensor only has optical sensors . It just doesnt seem like it is precise enough to try to determine if the pump is operating by the water level change after the pump shuts off.
When my new CME controller comes i will let you know if it changes anything.
Thanks for the help
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So, i finally figured out the problem. The temperature sensors were at fault. Even after replacing the computer i still had the same issue. I figured the only other part that may be used to sense water flow may be the temperature sensors. The ones that were installed in the machine were replaced a few months ago because the wire going into the probe for the water broke off.
All is well now, hopefully this will help someone out with a similar issue.
This really is a great machine when it is running properly
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Originally Posted by
pecmsg
Was never a fan of the CME but great story.
X 2. But It's good to know there was someone in our corner when they designed it.