DC return pump valve or rely on speed control

[speedstar]

In my fail safe accounting I am wondering if those who run DC return pumps, run them at full speed and gate off the output in the case of the pump flowing more than your drain can handle. Or do you just run it at a lower speed with no restriction valve and hope the controller does not fail in a full on condition?

thoughts opinions?

 

[MnFish1]

I think the likelihood that it would fail that way is extremely unlikely - but since you have a controllable pump - I would dial it down - it saves the pump - and it saves energy. I believe you can get a flow meter - that you could hook up to a controller - which would alert you if the flow was too 'fast'

 

[speedstar]

I think the likelihood that it would fail that way is extremely unlikely - but since you have a controllable pump - I would dial it down - it saves the pump - and it saves energy. I believe you can get a flow meter - that you could hook up to a controller - which would alert you if the flow was too 'fast'

Thanks, I account for way to many failure points for everything as my day job depends on it. I thought I was over thinking it. Thanks for the flow meter idea.

 

[Greg P]

If wanting to run a DC pump at less than full-speed, and being concerned if it could decide to run full-speed, having a secondary/emergency drain to handle the full flow of the pump is a good idea, or a float in the overflow box to turn off the return.
I'm still old-school and use an AC pump that doesn't fluctuate, is sized to my needs, and use my drain's gate valve to control my optimal overflow level on the main drain.
I've not yet heard of a DC pump controller deciding to go rogue, but I'm sure it's possible.

 

[speedstar]

If wanting to run a DC pump at less than full-speed, and being concerned if it could decide to run full-speed, having a secondary/emergency drain to handle the full flow of the pump is a good idea, or a float in the overflow box to turn off the return.
I'm still old-school and use an AC pump that doesn't fluctuate, is sized to my needs, and use my drain's gate valve to control my optimal overflow level on the main drain.
I've not yet heard of a DC pump controller deciding to go rogue, but I'm sure it's possible.

Thanks, I had always used AC as well, but this DC came for free with the setup, so it was new to me. And just have had a few DC speed controllers fail on me in various hobby and other applications in the past. It is planed to have an emergency drain, so hopefully at wide open it handles it. (drains are only 1inch in this setup)

 

[TheHarold]

+1 for speed control. Using a valve with a DC pump at 100% is less energy efficient, puts more work on the pump, will be louder, etc. I think you are more likely to induce failure than prevent it.

A proper pump/overflow combination should still be able to handle additional water via emergency drains. My return pump is typically set at 60%, but if it goes to 100% the overflow can still handle it, and I would be alerted within a minute.

I would get four alarms from my Neptune Apex:

1. Return pump wattage above set point
2. Overflow water level high (float switch at emergency overflow)
3. Return chamber level low (another float switch)
4. ATO error (after it is on longer than usual to fill up the return chamber).

Although I don’t have any automated response, one can program based on a single or combination of these indicators. For example if return pump wattage is high AND overflow level is high, shut off return pump for X minutes.

Apex is awesome

 

[RobB'z Reef]

In my fail safe accounting I am wondering if those who run DC return pumps, run them at full speed and gate off the output in the case of the pump flowing more than your drain can handle. Or do you just run it at a lower speed with no restriction valve and hope the controller does not fail in a full on condition?

thoughts opinions?

In my current experience in running COR-20's fit my return pumps and my goal was a reduced run rate to buy only hopefully extend the life of the pumps but to have room to adjust output in the event of the loss of a pump. That being said I put a gate valve on my main drain, a ball valve on my secondary and nothing on my emergency. You bring up a great question though about how do most DC pumps behave? They all come with some sort of controller.

This is where it gets interesting I think. I can only speak to the ones I've specifically used. I'm the case of neptune, it uses the last set power setting. So if you lose power and it's restored it will resume at whatever it was last set at. I've tested this without a neptune controller system. Perhaps other DC pumps behave differently.

At the end of the day I guess I advocate installing whatever valves you can. For the investment cost of doing it beforehand is worthwhile. I run my DC pumps at 50% and then used my valves to throttle back my drains because they were too efficient at that rate. Just my experience