Need help, External Pumps

[kc]

I had 3 MRK4 that I purchased in 1998. A week ago, one of them made a humming noise but not pumping water. Today, I took all of them apart from the sump, unscrewed the front part and cleaned inside the plastic housing and back which is the fan area. After putting all of them back in. All of them just had a humming noise but not pumping water.
Does anyone wants what is wrong. I hope I don't need to replace them...I just started restocking because the power outage wiped out my tank.

Thanks in advance
KC

 

[szidls]

Kc are all the pumps primed? That would be my guess.
Scott

 

[kc]

The input of the pumps are lower the water level on the sump, so I assume that it is primed.

 

[szidls]

You need to prime the output side also.
Scott

 

[kc]

How do I prime it? The output is 3/4" flex pipe, connect to a one-way check valve and then a ball valve.

Thanks
KC

 

[Scooterman]

Is the motor on the pump actually turning or is it just humming? Two things usually go out on motors, the brushes & the bearings, you can replace the brushes & lubricate it when needed! Also the Pump itself should be cleaned about every two years at least.

 

[kc]

When I unscrew the front part (volute), there is a big around thing on the motor. When I plug in the plug, it did turn. But the weird thing is I only took 2 pumps apart and just loosing the bulkhead on the 3rd pump. Now all 3 of them stopped.

 

[Scooterman]

These pumps been running since 1998? That is some years on them & getting power spikes won't help much either. Unless your familiar with motors or you could send them back for repair you may have more problems with them. The motor turned that pump but how fast was it, under load it may be bad. The typical motor if built well should have replaceable brushes, you would see two big screws opposite of each other on the front part of the motor, If you do, you may have an easy fix of replacing them. I'll see if I can find a schematic online maybe to see where they are & how easy it would be to replace them.

 

[kc]

The problem was cause by the Ca build up. After dip into the mu. acid, it looks like brand new. All 3 pumps are running now, however 2 of them are running very loud and not pumping as much as before. Do you have any idea what will be the problem?

 

[Scooterman]

Did you lubricate them? If you didn't keep them up I'm sure they could use lubrication, possible bearing replacement & or the brushes. That is why it is recommended to keep them clean which reduces wear & un-necessary strain on the motor but after all these years that was a good run I'd say. Hard to diagnose on-line that is my best guess!