Troubleshooting a well pump

[Time to grow]

About a month ago, I purchased a new Venz 1hp (VR 100) brass impeller well pump. It is mounted at the base of a 2000l water tank and designed to pump water from the tank for drip irrigation. During installation testing, the pump worked flawlessly. I ran it a couple of times shortly after installation but total combined run time is less than one hour. Then the rain started in the Nakhon Sawan area so I haven't needed it until today. Now, when I energize the pump, it rotates at about 2 RPM in sort of short jerky steps. The pump is 220V, 5.5A, 50Hz as is the power supplied. There are no closed valves or other restrictions to the supply side or the pump. The problem looks to me like it must be electrical. With only one hour of run time, it is unlikely the brushes. I am wondering if maybe the 20 µF capacitor has gone bad. Does anyone know if a bad capacitor would cause this type of problem?

[Wirejerker]

Does it turn easy by hand. The maybe something in the pump itself. Animal , vegetable, mineral or Catalytic action with the brass impeller.


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[Fruit Trader]

Venz pumps have warranty support.

 

Venz Pumps

T.N. Metal Works Ltd
92/1 Moo.7 Petchkasem Rd
Kratumban
Samutsakorn 74130
Phone 028102000   
 
Service Center
Phone 0852528989
[email protected]

[bankruatsteve]

I have a 2.5 hp bore hole pump that will sometimes just buzz instead of starting up.  I removed the cover where a fan and rotate that.  Then it usually starts up.  But now, when it doesn't start, I just go over and spin the fan (make sure the right direction) and off it goes.  In my case, I think ants so I spray whenever I see them.  i do keep it covered from the rain.

[Time to grow]

20 minutes ago, bankruatsteve said:

I just go over and spin the fan

Thanks for all the tips. I will pull off the fan shroud and see if there is excessive resistance when attempting to turn the fan. 

1 hour ago, Fruit Trader said:

Venz pumps have warranty support.

I called the service center phone number and it is the wrong number. I was able to speak to someone at the office number. They tell me that the capacitor could be responsible for this type of failure.

 

 

[bankruatsteve]

Seems like the capacitor wouldn't go bad this soon but whose know.  My old electric mower got where it wouldn't start (just buzz).  I replaced the capacitor but didn't help - I think the start windings bad.  Anyway, a kick start by turning the blade with a stick would get that going too.

[Artisi]

More than likely just gunk from the water locking its rotation, as you said - try rotating it by hand then hit the start button. 

[Fruit Trader]

Two check before moving forward.

Check motor is free to rotate using the fan blades behind end cover.

Check there is correct voltage reaching the pump. Example - Ants under a pressure switch contacts can cause intermittent or low voltage.

Photo - Similar installation using Venz VM100 on shallow bore.

 

[Time to grow]

Well two strikes so far. Much to my surprise the local hardware had the capacitor. I went ahead and replaced it. I assume capacitors are not pole specific? The original capacitor had two white leads with no markings to distinguish them. The replacement capacitor has a blue and a brown lead. So leaving open the possibility that I have possibly wired up the capacitor backwards, there is no change. When I energize the pump with the new capacitor, it continues to spin at about 2 RPM.

When I spin the fan by hand, there is more resistance than I would expect. Not sure how to quantify that, in foot pounds I guess. The resistance is felt evenly all the way around. In other words, it doesn't feel like the pump is catching on something, releasing, and catching again. I tried energizing the pump while simultaneously spinning the fan as quickly as I could, numerous times to no avail. Then I tried wrapping a string around the pump shaft and pulling quickly to get the pump spinning faster, still no joy.

I guess I am going to have to pull the pump out and disassemble it to find the problem. I was hoping I could avoid this.

[Fruit Trader]

5 minutes ago, Time to grow said:

I guess I am going to have to pull the pump out and disassemble it to find the problem. I was hoping I could avoid this.

If you do not want to send it to Venz.

 

Before dismantling you need to check for correct supply voltage and motor windings using a meter.

If these are ok remove the pump front cover to inspect for debris around the impeller. If non found you can then remove the impeller to expose ceramic seal and bearing.