Question for Little Giant pump users - Page 2

ldzielak · #11 07-06-2002, 03:02 PM

Also forgot to mention I have my pump seize on me once, when I turned it off for a water change. On start-up 10 min later, is started really slow then stoped. When I unpluged it and pluge back in you could see some movement, but then nothing.

I was going to get the motor re-wound locally then after opening it up, found out the motors are not serviceable. The local LG rep does stock them and parts too.

But I found out if you remove the impeller there is no problem runing the pump dry. I removed everthing I could, mag drive assembly and all. I could not even turn the motor with a large pair of chanel locks. So as a last resort, I used WD40 down the oil holes. Tried the pump and then it started to turn. Left it on and dosed heavily with WD40 and it just go better. Then followed with contact cleaner then used the recomended weight oil. Guess the dust and dirt over the years turned the oil into grease and then glued it closed. Was fine when the pump was hot, but after it cooled, it was screwed.

I will do this on a yearly maintenance, since my pump is exposed to dust right now. Did not notice a temperature difference with the fresh cleaned motor compared to before.

Lee

[ 06 July 2002, 11:04: Message edited by: Lee ]

Delphinus · #12 07-07-2002, 02:20 PM

No screens on the bulkhead.

Hmmm. Conceivably, I could, with very little effort, switch to a 1.5" bulkhead on the sump, then go 1.5" pipe through the two 90 degree bends, and then step the pipe down to 1" just before the pump intake. I wouldn't have to rethink where I've placed my pump (which to me right now is the priority; which I am trying to work around).

How can a person tell if they are starving the pump input? Are there any signs a person can watch for? The flow this pump is putting out is substantial. I have no frame of reference to which I could compare.

Canadian Man · #13 07-07-2002, 02:45 PM

Tony,
I dont believe there is any obvious sighns of staving your pump other than the obvious.
1.Excess heat
2.I believe a 1' bulk head flows something like 900gph or something close to that and your pump pulls more than that, right?

That's how i came to that conclusion.

JimE · #14 07-07-2002, 03:12 PM

The 4mdq max is 850usgph@1'tdh and flow decreases from there as head increases. Obvious signs of starvation are excessive pump noise due to cavitation (gravel/marbles going through pump) & *not* motor overheating. IME they do run hot and if the pump is new it will smell for a bit while "breaking in". Sure way to tell whats going on is see if you can get a hold of a meter and check the amp draw. If thats below motor specs you are fine. If not.... [img]smile.gif[/img]

Jim

ldzielak · #15 07-07-2002, 03:25 PM

Delphinus,
You may pump localtion will hopefully not change, if you have some straight pipe run. 1.5 90's take up more "room" than the 1" by a large factor. Rules would be most direct path and if it's not, there is no harm in oversizing. Personaly I would like to have 2x the flow capacity for my piping all the way directly up to my pump.

In my case, I will be re-doing mine, not for more flow, I already have too much, but to see if I can make the system quiet.

Delphinus · #16 07-07-2002, 03:33 PM

Ok, this is helping my paranoia. Thanks very much for all the great info, guys.

Any suggestions where to get an appropriate amp meter? How expensive are they? I don't think my little $10 0.5amp multimeter is going to cut it... if I do a measurement on the pump draw.. :rolleyes: [img]smile.gif[/img]

PS. Cavitation. DUH. I can't beleive that didn't occur to me. And I work for a oil and gas, water and wastewater pipeline SCADA vendor!!

Frightening. Well, no, I'm not at work now, so I'm allowed to be dumb. :D Well, the good news is that the pump is not cavitating...

[ 07 July 2002, 11:37: Message edited by: delphinus ]