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Thread: Cor 20 questions

  1. #1
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    Cor 20 questions

    OK so I got my Cor 20 going for the first time and I'm confused about two things
    First Fusion states wattage is 45 however I have a Kill-a-Watt plugged in and it shows about 10 watts higher. Why?

    Also I'm a little confused about the calibration. I understand the high calibration mark but not the low one. I did the calibration and set it up for only one percent when on feed mode however even at only one percent it still has return water coming down! I don't want food going down the drain! I thought it would just be enough so nothing would drain. If that's going to be the case I rather have it off totally in feed mode.

  2. #2
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    I don't have one to test, but Neptune probably listed the wattage after conversion to 24V just like they show for the COR15 and WAV that pull power from 1link. A typical DC power supply is 80-90% efficient, which would explain the extra 10W assuming I was correct about where they calculate wattage from.

    You might be an engineer if...You have no life and can prove it mathematically.

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    I have a COR-20 and also had water flowing into the DT in feed mode at 1%. I added a tee to the return line and put in a gate valve that I opened just enough to stop the flow into the DT at 1%. I then had to increase the high mark a couple of percentage points to make up for the gate valve being open.

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    Quote Originally Posted by jamesreich View Post
    I have a COR-20 and also had water flowing into the DT in feed mode at 1%. I added a tee to the return line and put in a gate valve that I opened just enough to stop the flow into the DT at 1%. I then had to increase the high mark a couple of percentage points to make up for the gate valve being open.
    Thanks for the suggestion however I think it's just too much trouble instead I just programmed it to go to 0 during feed mode
    I really don't understand the big deal in not allowing the pump to basically go off for feed mode. What is the point?

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    If you keep the water from flowing back down the return line when in feed mode you prevent air bubbles going into the DT when you start the return pump after it has been at 0.

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    The main reason is to keep water level in the display and sump from changing so much and also prevent water from back siphoning through the output.

    You might be an engineer if...You have no life and can prove it mathematically.

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    Quote Originally Posted by zombie View Post
    The main reason is to keep water level in the display and sump from changing so much and also prevent water from back siphoning through the output.

    You might be an engineer if...You have no life and can prove it mathematically.
    And why would that be a issue?

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    Quote Originally Posted by marksw View Post
    And why would that be a issue?
    It usually isn't an issue for most people unless the output from your return is low in your main tank or you have a small sump compared to your display size.

    You might be an engineer if...You have no life and can prove it mathematically.

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    First, the power displayed on the dashboard is the power going to the pump itself. The power on the kill-a-watt is the power being drawn from the wall which includes the pump plus the controller plus the power supply.

    There are several potential issues with water back-siphoning into the sump when the pump is turned off:
    • If the pump is restarted while water continues to flow backwards, it will generally cause an error and failure to restart
    • back siphoned water can cause the sump to overflow (If this is actually an issue then you probably have a poorly/improperly designed system, but that's another discussion)
    • dropping water level in the display tank may cause power heads to entertain air
    • High water levels in the sump can cover float switches intended to be emergency backups and get debris on them (normally you should check and clean these as part of routine sump maintenance, so this shouldn't be an issue, but I'm listing it as at least a theoretical one)
    • Restarting of the return pump after the water has siphoned back to the sump makes a lot of splashing, bubbles and noise. Having the pump at a 'static' flow speed means the system starts up more quickly, quietly, with less splashing and achieves steady state faster.

    The last reason is the real reason most people do it. If none of these matter to you, there's nothing particularly wrong with having the low threshold set to 0.

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    Quote Originally Posted by Sleepydoc View Post
    First, the power displayed on the dashboard is the power going to the pump itself. The power on the kill-a-watt is the power being drawn from the wall which includes the pump plus the controller plus the power supply.

    There are several potential issues with water back-siphoning into the sump when the pump is turned off:
    • If the pump is restarted while water continues to flow backwards, it will generally cause an error and failure to restart
    • back siphoned water can cause the sump to overflow (If this is actually an issue then you probably have a poorly/improperly designed system, but that's another discussion)
    • dropping water level in the display tank may cause power heads to entertain air
    • High water levels in the sump can cover float switches intended to be emergency backups and get debris on them (normally you should check and clean these as part of routine sump maintenance, so this shouldn't be an issue, but I'm listing it as at least a theoretical one)
    • Restarting of the return pump after the water has siphoned back to the sump makes a lot of splashing, bubbles and noise. Having the pump at a 'static' flow speed means the system starts up more quickly, quietly, with less splashing and achieves steady state faster.

    The last reason is the real reason most people do it. If none of these matter to you, there's nothing particularly wrong with having the low threshold set to 0.
    Thanks for the the best explaned answer to both questions!

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