I have had some bad luck with a pump. Pump was bought in February 2018, an installed in March 2018. I am currently on my 4th impeller. Someone asked if I had a gate valve to keep the water from returning into the pump and possibly causing the impeller to turn in the opposite direction, when power is turned off. Well I dont. But that is when the pump fails. Knowing that i never turn it off. But if i have had a power outage or any other reason that the pump had to power down it wont work. The impeller is stiff, and wont turn. Any thoughts?
DC Pump question
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Brad Miller
Valuable Member
there are a couple things it could be...
Note: a check valve on the discharge is always installed to keep the water from siphoning out of the tank backwards into the pump and sump area (so as to not overflow your sump when the pump shuts off)
But to help you further;
1. What brand and model Pump is it ?
2. How many feet is it from the pump to the discharge into the aquarium (this is a return Pump, right ?)
3. What controller are you using ?
4. When you say it fails, explain exactly what you're noticing besides the impeller is tight now.
Note: a check valve on the discharge is always installed to keep the water from siphoning out of the tank backwards into the pump and sump area (so as to not overflow your sump when the pump shuts off)
But to help you further;
1. What brand and model Pump is it ?
2. How many feet is it from the pump to the discharge into the aquarium (this is a return Pump, right ?)
3. What controller are you using ?
4. When you say it fails, explain exactly what you're noticing besides the impeller is tight now.
VaReefer
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1. Reef Octopus VarioS 4
2. 3ft yes return pump
3. Using the controller that comes with the pump
4. The pump will not restart. Since I am on my 4th that means I have 3 bad impellers. One, which was the 2nd failure, the rubber bushing went bad and no longer keeps the impeller straight. The other 2 are stiff. So the pump/controller recogises that the impeller is not turning and shuts down.
https://www.coralvue.com/media/cata...d6e5fb8d27136e95/r/o/rodc5500impeller_1_4.jpg
This is how the impeller looks. in the pump the big disk is stationary. So if you take the impeller out and try to turn the impeller while holding the big outer disk, the impeller is very hard to turn
VaReefer
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Won't turn. only way I can get it to work is to buy a new impeller. Coralvue wants me to send it back so they can check it out. But I have already sent it back once when it have a bad power supply. At this point If I cant figure out what the issue is, I will be buying a new pump and it wont be a VarioS.
Heart of Dixie
Active Member
It is probably a permanent magnet motor. The impeller is the armature and has steel inside. Inside the body of the pump housing are magnets therefore when the power is off, the poles in the two line up and it will be difficult to move. If there is too much head pressure or there has been a loss of field it may be too much for the pump to overcome and it shuts down on the inrush of current. It might be a setting in the dc controller, too. What happens if the pump is taken out of the system and just sitting with no load, will it start then?
Brad Miller
Valuable Member
After digesting what your having happen, seems to me there's not much you could be doing wrong.
The impeller shouldn't get tight at the front bushing, unless there's something in your water reacting adversely on the bushing.
Only other thing other than a chemical reaction to the bushing would be if there is a calcium build up on the bushing and shaft on the impeller end. (Front drive bushing should turn freely)
The impeller shouldn't get tight at the front bushing, unless there's something in your water reacting adversely on the bushing.
Only other thing other than a chemical reaction to the bushing would be if there is a calcium build up on the bushing and shaft on the impeller end. (Front drive bushing should turn freely)
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VaReefer
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I agree. but what has be baffled is it occurs when the pump loses power or power is turned off. I have sent an email to coralvue asking if the water rushing back down will effect the impeller. I don't need a gate valve, because my sump does not over flow, but if it fixes my pump problem then I will install one.
Brad Miller
Valuable Member
A gate valve is a valve that you use to throttle flow, a check valve will stop reverse flow.
Sometimes a pump spinning backward or forward can generate a small amount of voltage, it I don't think that's your problem here. That won't ruin a front bushing and make it tight.
Maybe it's still turning backwards while the pump starts back up, that may be an issue causing it to not want to run the right way.
Install a check valve and see if that works.
Sometimes a pump spinning backward or forward can generate a small amount of voltage, it I don't think that's your problem here. That won't ruin a front bushing and make it tight.
Maybe it's still turning backwards while the pump starts back up, that may be an issue causing it to not want to run the right way.
Install a check valve and see if that works.
Brad Miller
Valuable Member
I meant install a check valve get a new impeller and see if that corrects the issue
Heart of Dixie
Active Member
It sounds like an electrical issue to me. If you have to purchase a new impeller each time you shut the pump down something is either causing a loss of magnetism in the field, in the armature (the impeller in this case), the dc control is set too low or the motor is just not strong enough. DC motors have been the workhorses of variable speed, high torque applications for years. They probably need to make the controller regenerative or add a resistor / dynamic brake so if the pump in fact can run backwards when power is on the voltage it generates has somewhere to go.
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