effluent pump

[6sunset6]

Maybe someone here has a clue. I pump effluent 500ft 12 ft uphill to my septic field. I have a duplex pump system with an alternating relay with a second pump alarm. The pipe line is 2". The pumps run around 5 min every 2-3 days. So each pump runs maybe 5 min a week say 5 hours per year.
They are .5 hp 230volt 1 ph pumps. The 12 foot head is well within the pump curves. There is a weep hole to drain the head on shut down. Some of the pumps have weep hole in the base. I have had 3-4 different manufacturers of pumps.
The problem I have is the failure of the pumps. fail to start. Resistance across the two power leads is ok 6-10 ohms. When I open one up usually the centrifugal switch has failed. Out of warrenty of course. Oh yeah 3 years is about average although one lasted 15 years. This is down a 9 foot confined space and I have been doing this for 20 years. Today I replaced one and banged the other around working on pipes and then it failed. I am getting too old for this.
Anybody have a clue?

 

[RedNeckRacin]

TO me it sounds like your pump is way over designed if its running that little? Have you attempted to have anyone actually do the head calculation for you? 500 ft is a pretty decent run of pipe and there are obviously restrictions in the system besides the friction loss in the pipe. From the website below, a guesstimate of an additional 8ft of head for your 500 ft run, plusthe 3 feet required at the end of the laterals, plus an unkown friction loss from elbows and tee's and you aren't requiring a whole bunch of oomph. Looking at liberty effluent pumps here :https://www.libertypumps.com/Data/EngineerSpecifications/FL50_R11-12.pdf It looks like you are pushing around 50-55 gpm depending on what your losses are. That sounds pretty wicked for a septic pump???






PVC Pipes - Friction Loss and Flow Velocities Schedule 4

 

[RedNeckRacin]

TO me it sounds like your pump is way over designed if its running that little? Have you attempted to have anyone actually do the head calculation for you? 500 ft is a pretty decent run of pipe and there are obviously restrictions in the system besides the friction loss in the pipe. From the website below, a guesstimate of an additional 8ft of head for your 500 ft run, plusthe 3 feet required at the end of the laterals, plus an unkown friction loss from elbows and tee's and you aren't requiring a whole bunch of oomph. Looking at liberty effluent pumps here :https://www.libertypumps.com/Data/EngineerSpecifications/FL50_R11-12.pdf It looks like you are pushing around 50-55 gpm depending on what your losses are. That sounds pretty wicked for a septic pump???






PVC Pipes - Friction Loss and Flow Velocities Schedule 4

 

[6sunset6]

Thats pretty much the pump I have. The ones I am putting in now are Meyers 4/10 hp. About the smallest made. The system is designed to pump 250 gallons at a time over the whole field. That's why it runs so infrequently. There are only two of us . I don't think thats why the centrifugal switches are failing.
They are not short cycling which I would expect to cause failure. Maybe the weep holes are plugged and the pumps are starting against a head pressure. That would cause the centrifugal switch contacts and or the starting coil to burn out.. I saw that once the contacts fused shut. Well I have two bad pumps right now so when I open them up I will post my findings

 

[Mendonsy]

I suspect the environment where the pumps are located is at least part of the problem. Is the that area normally wet or high humidity?? Is there any chance of methane buildup?? Is the atmosphere corrosive?? Any of those could cause problems with single phase pump motors that have start and run windings.

 

[RedNeckRacin]

I suspect the environment where the pumps are located is at least part of the problem. Is the that area normally wet or high humidity?? Is there any chance of methane buildup?? Is the atmosphere corrosive?? Any of those could cause problems with single phase pump motors that have start and run windings.

Are you serious? The pumps are submersed in the effluent from the septic tank.

 

[6sunset6]

Exactly total submerged in the worst stuff. They are supposed to be otherwise they overheat. Although it is hard to see overheat in a 5 min run every 3 days. Methane, hydrogen sulfide and one other I can't remember. I posted here a few years ago about going down into the space. The best answer I got was if a candle burns you are ok. I did that , after I opened up and let it vent for a bit. Candle burned fine. To get rid of the smell and get some fresher air down there I put a shop vac hose down to a foot off the bottom and let it run . Works well. I don't breath throu my nose either. I think there are more fatalities by falling, knocking yourself out and drowning than lack of oxygen. Just a side comment. I would like to rail mount those pumps but that means I have to cut the manhole off, and replumb the bottom. ahh I am 70 I can change pumps a few more times . Does anyone know what that black stuff is that builds up on pipes, pumps and everything else? It is really hard to wash off.

 

[Mendonsy]

Well, if you are using that type of pump it is no big surprise that they need to be replaced. There is no way to seal them up well enough to keep the bad stuff out permanently.

 

[DFB]

Interesting discussion to me because my system design is almost identical with duplex alternating pumps and a uphill mound. Except my overall run is much much shorter. I have had the same goulds for more than 10 years of usage now. How are the wiring connection done with yours mine are hard wired into a weather proof sealed box no plugs we cut them off but it still is located inside on the ceiling of the tank.

Once I had problems with the high level alarm "ghosting" the alarm would sound faintly and continuously and it was in the basement so you could hear inside the house especially at night. Turned out there was moisture in the junction box and I guess there was some electrical bridging going on. Getting in there opening it up and drying it out plus resealing fixed the problem. Obviously nothing to do with your problem but I can relate to the nastiness of getting down in there .

I wonder could an obstruction in the line run be causing the pumps to burn out?

I can easily see the drain back from the weep holes happening on my setup.

 

[6sunset6]

Mine was originally spliced in a waterproof box high in the chamber. With pump failures I got tired or soldering and heat shrinking sleeves and the box was not tight anyway. So I drilled a 3" hole through the side of the chamber very high up and installed a 2" PVC conduit to a new box out side. Put outlets in it and plugged in the pumps. The box is not deep enough for straight in plugs so I cut them off and used right angles. Makes it easier to feed the linecords through the conduit as well. caulked all the feed through spaces. Two of the float switch line cords are still spliced in the chamber box, they have not failed in 20 years so leave alone. The third switch connection corroded at a bad splice and I ran it through the new conduit. I had condensation in the control box in the winter so I put a short heat tape around the inside. Took care of it.
I have yet to take the first failed pump apart. later this week. These pumps should really be rail mounted so they can be pulled out from the surface.

 

[gghb]

most effluent pumps vent through a small tube in the cord if water or corrosive gas gets in it will ruin the pump. Learned this the hard way in 40 years of installing septic systems. Meyers pumps are close to bullit proof.


Greg

 

[Billrog]

When I install those pumps I always bring a loop up to the top of the pump chamber with a union so it isn't necessary to get down inside to change the pump. All electrical is hard wired to either the garage or basement where the controller is located so there are no connections where high humidity can corrode them.
The pumps generally last for years & your not using a lot of water the min. design flow rate for your home would be 750 gal. per day. I only use 1 pump if it fails the warning alarm goes off giving you 3 days to fix or replace it or the real alarm goes off and there's no way to shut it off until the power is cut off.
If your tank has been pumped within the recommended scheduled I can't see any restrictions being a problem not when they are pumping 50 gal. per min ( 240 gal. in 5 min.) Are there inspection ports at the end of your field runs for you to check ?

 

[6sunset6]

There are no inspection ports at the ends of the laterals. There is a box at the top of the field where the pump line discharges into the start of the laterals.
The field design is such that the whole field takes the discharge volume all at once . The board of health guy like it. Said the field would probably last forever. If I pull the manhole cover I can see the level going down pretty quickly , has to be going somewhere that fast. Anyway the pump fails are fail to start except one that had the start points weld shut. Two had broken plastic springs in the centrifugal mechanism . One had a bad splice in the box, thats the spare that just went in. A Grainger Zoeller is the one that just failed 3 years old . A meyers just failed and it is still in there waiting on a replacement .

 

[6sunset6]

I opened up the Zoeller pump. Impellor turned freely ,Upper section with power feed through, clean. Drained oil from the next chamber , which had a lot of grey particles in it, not a good sign,
Second chamber popped right off.Clean of effluent however the starting capacitor, no centrifugal switch, was blown right in half . Hmm $500 pump, Grey grit distributed all thru bearings and close distance between stator and rotor, got to get capacitor and connect with oil tight connections, got to get clean oil and some how flush the motor case, and hmm how long would it last. Meyers are $260 scrap it. Now why did the capacitor blow. Heat not likely pump is immersed in water 100% of the time. Impeller jammed it was not. Load on the pump well could be but even if the weep hole did not drain the pipe , and this is for freeze prevention not unload the pump, it's hard to see a centrifugal pump like this failing under a 12ft column of water . It only 6 psi in a 2 inch pipe. Lets see if I can post a picture

 

[RedNeckRacin]

Wow, I'm really suspicious of your power source to the pump now. I'm no electrical guru. Once you got out of the plumbing calcs, I'm out of my league....

This isn't helpful but it may lighten the mood. Do you guys eat alot of Mexican food?

 

[6sunset6]

Funny The capacitor was made in Mexico.
grainger $52 for capacitor plus shipping
light weigh mineral oil I am guessing $47/gal plus shipping
This is just for kicks I am not going to try and save the pump. I could do everything but get all the gunk out but who knows when it would fail again.
I will post again when I get the new meyers about a week and get out the other meyers that just failed.
I was just thinking, If I find a blown capacitor in the meyers then perhaps the pumps don't have enough start hp regardless of the curves . Read bigger pump more $$.

 

[Billrog]

Just checked to see which pumps I've been using & could only find the whole salers quote sheet no names for the dam pumps.
1hp EFF Auto 230v 1PH pump 751.80
& 4/10 115v sew pump auto 20' 301.00
Wish I had more knowledge to help you with the pumps , check that they have a good power supply. Sure at a loss why the capacitors would blow. Maybe check out ebay for a capacitor $57 sound a little on the high side.

 

[6sunset6]

The mystery continues. I have hour meters on the pump circuits. In two years since I read the numbers last the pump that failed ran twice as many hours as the pump that did not fail. And it is a little bit bigger pump. But 24 hours over 2 years is not a lot. . I did notice the the check valve on the opposing side was leaking at the joint. That would do it.

I just spoke with a guy who is a sump motor expert. He said long start times are really hard on start capacitors. He thought the problem was clogged weep hole and or stuck check valve. He suggested taking out the check valve but that would only work with one pump. I don't want to do that so I guess the answer might be a yearly PM on the check valves and the weep hole. Maybe make the weep hole a little bigger.

 

[6sunset6]

All right 2 pumps with blown capacitors. $51 for one and $121 for the other. I guess they are submerged in oil so they are pricey. I found same value caps for $6 from Mcmaster carr. Plus some oring material as one swelled. Bad material from China I would guess. The caps are a physically little bigger but there is a ton of room under the hood. Plus no moving parts. One cap had electrical push on tabs in the oil so nothing special there. I strained the oil through a tee shirt filter. It probably not as clean as new and maybe the lower bearing will wear out sooner. But one of those pumps goes for $1000 now the other is $500.
So For $30 I will see if they run. If they do good for hot standby short term spares. The pump I am using now is a Meyers at $260 but it takes a week to get it.
I have one Meyers not running now and the new one just came . So when I open that one up I will post whats what.
I am seriously thinking about getting a contractor in here to remove the manhole cover and the top concrete precast for it and replace it with a precast cylinder and the pumps on a lift out rail. I will get some quotes and see. I still have a backhoe and tractor but getting to old for all that activity.
I still have not figured out the hard start . I am afraid someone will tell me to put in a bigger pump , over $1000 and there are 2 and then have the same failure. They certainly move liquid when they run.

 

[jlawso21]

I have a similar situation. You can look at Liberty or Ebarra pumps, very expensive. I just had one worked on. It stopped working because it wasn't wired properly on installation 8 years ago. When it was rewired it works now. The first pump lasted about 12 years. The guy who worked on it said to expect 12-20 years out of them.

They sell for $1200 to $2000, it's 2 horsepower which may be more than you want but you may need something stronger than you have now.