Sump Pump Discharge Throttle - Solution Needed

[Lindsay]

I desperately need some pro advice - I have a very unique situation - please read all.

Questions:
1 - Will ball valve on sump pump discharge put too much strain and break or shorten lifespan on the unit?
2 - Will ball valve throttle the flow too much for a 1/3 HP pump to get the waste up a 11-13 foot vertical pipe?
3 - Please read my explanation below, are there any other solutions that come to mind?

I live in a old brewery converted to loft - space, therefore, NOTHING is a normal residential type setup.

The drainage is located on the 2nd floor, my kitchen is on the first floor. At the advice of the maintenance staff (when we discovered a drain pipe we had been using was no longer functional as a drain pipe...) we attached a sump pump to our kitchen sink drain to pump the sewage up to the main drain line on the 2nd floor. We use a sink strainer and are very careful about waste going into it.

One neighbor shares this main drain line with us, and has been having sewage gas and bubbling coming up into the kitchen sink (theirs is on the 2nd floor). I do know that he personally installed a drainage vent somewhere on his side.

This used to be a problem all the time when we had a 1/2 HP pump, but seemed to get resolved when we downsized to a 1/3 HP pump.

Now, the current pump (Liberty Pumps 404 1/3 HP, 115V Residential Drain Pump) seems to have a broken switch - which we will attempt to fix soon. However, in the meantime, we have to run it manually (plug in / unplug bypassing the switch).

I believe my fiancee was running it for close to 6 seconds at a time, and I believe it normally only runs for 1 - 2 second intervals. AAAAANNNNNNND the sewage bubbling up in our neighbor's sink is happening again. I believe this is as a result of the longer "bursts," my fiancee was doing, but I'm not sure my neighbor is understanding that. We have since shortened to running it in 1-2 second bursts and I haven't heard anything but unsure if it's persisting.

Aside from just running it in shorter bursts / fixing the switch, he's asking us to install a ball valve on the pump discharge line. I'm not opposed to this, however, I want to make sure it won't damage the unit. If we did this, it would appease him and potentially future-proof us from this happening again - keeping peace with neighbors who share a very thin wall.

- Is there any danger in damaging or shortening lifespan of the unit if we install a ball valve?
- Are there different types of ball valves / a particular one we should look into?
- Will a ball valve prevent the waste from getting all the way up to the main drain (approx 11 - 14 feet vertical before the drain pipe goes horizontal and feeds into the main drain line.)
- Any other suggestions which don't involve doing into our neighbor's plumbing or the main drain line?
HELP!

 

[Diehard]

What is referred to as a "full bore ball valve" has a minimum ID of at least the nominal size of the pipe and sometimes larger. So based on that it should make no difference when wide open. However, you haven't made clear the intent of the ball valve. One can only assume it's to throttle down the flow a bit based on the description of the problem.
Of course there is no mention of exact size and type of pump, nor how it is arranged. Typically most pumps actually use less power as the flow is reduced and the pressure rises.
Simply look at the mfr's name and model no. of the pump to get a definite answer to your question. It may even have solids handling capabilities negating the concern for being "very careful about waste going into it".
On the other hand you wouldn't want to throttle down a valve opening and affecting it's solids handling capabilities. What pump do you have?

For you reference, HP is not always the best way to compare a pumps capabilities of flow vs pressure.

 

[Lindsay]

Thank you so much for your reply!

The purpose of the ball valve (at the request of the neighbor and arising from his research) would be to reduce the pressure in the discharge line in hopes that it wouldn't put so much back pressure on his drain and cause the gas and seepage up into his sink.

I mentioned in the post that the pump is the "Liberty Pumps 404 1/3 HP, 115V Residential Drain Pump" - I don't know if you needed different information? Forgive me, I'm a photographer - I definitely don't have a background in plumbing of any type, but am doing my best to research and try to become informed about my plumbing situation.

I've made a picture / diagram with the layout - perhaps that would be helpful? The discharge line leading out of the pump is 1 1/2"

 

[Diehard]

Great composite picture. Worth a thousand words.

Sorry I forgot what I read on your pump name, etc and asked again.

Okay so obviously the ball valve is to create a resistance and reduce the flow. Based on that pump info, it would be capable of pumping out a flow rate of about 15 gpm at 15 feet, or a bit less with friction loss.(Probably close to what it's doing now.) Since the pump is capable of pumping 4 gpm up to 20 feet, I would think you should be alright.

Now typically you'll see that ball valves are not recommended for throttling purposes. That's primarily based on the fact that it's non linear relative to the amount of movement of the ball vs the amount of flow regulation.

I found this article for you in case someone mentions that.

"Ball valves represent a modification of the plug valves with a spherical instead of a tapered or cylindrical plug. Advances in materials, primarily polymers, plus improvements in design, have reduced the cost and extended applicability of ball valves.

Ball valves are relatively low in cost; they open and close with one-quarter turn of the handle; provide unimpeded flow through the full bore with minimum pressure drop; and their handle position shows immediately whether the valve is open or closed. In addition, they are easy to clean and repair, and the self-wiping action of the seat as the ball-plug rotates prevents any buildup of contamination to impede full closure of the valve.

Ball valves were developed as on-off valves without much attention given to throttling characteristics. However, design improvements have suited ball valves for some types of flow control, such as throttling the flow of air at differential pressures as high as 1,000 psi. The bulk of the control does not occur with a minor movement of the handle. Only 3% of total flow occurs at 10\#161> of handle travel, 10% at 30°, 30% at 56°, 50% at 70°, and 80% at 82° or 91% of full open. Thus, a ball valve has relatively good throttling characteristics at low flow."

Good luck!

Oh ya...just remembered. I have to wonder if your neighbors sink trap is properly vented. That bit of pressure your discharge is causing should be handled by a vent. I did go back and see you mentioned, "that he personally installed a drainage vent somewhere on his side." That vent should be downstream of their trap.

 

[Diehard]

Refresh your page. I added some more text as an edit.

 

[Lindsay]

You are a godsend.

Can I just ask for clarification to see if I've understood properly?
Also - just to get my fiancee on board and prove that I'm getting good info, I see it says retired on your profile. Are / were you a professional plumber?

- The ball valve won't damage or put too much strain on the pump unit to shorten lifespan (my biggest concern)

- The ball valve won't impede the flow to any extent further than we turn the knob, which is a non-linear amount of "blockage" in relation to degrees the handle is turned

 

[Diehard]

View attachment 20686 View attachment 20686

You are a godsend.

Can I just ask for clarification to see if I've understood properly?
Also - just to get my fiancee on board and prove that I'm getting good info, I see it says retired on your profile. Are / were you a professional plumber?

- The ball valve won't damage or put too much strain on the pump unit to shorten lifespan (my biggest concern)

- The ball valve won't impede the flow to any extent further than we turn the knob, which is a non-linear amount of "blockage" in relation to degrees the handle is turned

I was never a licensed plumber. I worked with my father and then with my older brother as a plumbers helper when I was young.(A very long time ago.) Then I slowly(long story) worked my way into plumbing engineering for a consulting environmental engineering firm who primarily designed water and wastewater treatment plants. Many misc. courses and OJT(on the job training.) Could have been grandfathered in as a professional plumbing engineer in Mass. but never bothered since I was close to retirement anyway.

There are a lot of good professional plumbers on this forum with a lot of experience.

I assume this is a centrifugal pump,which typically can run all the way to their max head capacity with zero flow. In other words against a closed valve. But like I mentioned earlier, I would simply call Liberty Pump and have them confirm it. Their literature shows the max head at 21 feet, which is at zero flow, or a closed valve. No different than trying to pump up a column of water 22 feet high. It actually uses less juice/power at the higher head/less flow condition.

Some of their printed specs...
· HP 1/3

· Voltage 115

· Amps 5

· Inlet 1-1/2"

· Outlet 1-1/2"

· Vent 1-1/2"

· GPM of Water @ 5 Ft. of Head 30


· GPM of Water @ 10 Ft. of Head 25


· GPM of Water @ 15 Ft. of Head 15


· GPM of Water @ 20 Ft. of Head 4


· Max. Head 21 ft.

Your last statement is correct. I suppose the way to do it is to slowly turn the valve from the full open position towards the closed position, until the problem is eliminated. And at the same time you may have a feel for how fast it is pumping out the sink waste. Of course it's acting as a sump with a float but you could probably determine the flow rate by timing a known amount of water out of that unit. If you know what I mean.

You probably already have literature on he unit with telephone number but since I had it in front of me, I made a copy. You'll see the performance curve on this page as well. Just an FYI...the pump ONLY runs on points on that curve based on the back pressure in the discharge line.

 

[Diehard]

I kept going back making little edits, in case you were on this page. You would have to refresh it to see them.

 

[Lindsay]

Thank you thank you thank you thank you!!!! You are a wealth of knowledge!

 

[Diehard]

Just a parting thought.
If your neighbor installed an AAV(Air Admittance Valve) as his drainage vent, then that could be the reason they were still getting bubbling up their sink. An AAV only lets air into the system and not out, as a real vent would.

 

[Matt30]

**edit

Brain fart. Disregard

 

[frodo]

Lindsey
I disagree with Mr Diehard
After looking at a blow up of your sink drain tie in.
i have this to say
The tie in is not up to code, You have tied into the sink line horizontally
when it should be tied into the drain line from the top and, you are tied in upstream from your neighbors
when it should be down stream, I suggest
that you tie into the sewer line down stream from the upstairs sink
and make that tie in as close to 5' away from the upstairs as possible

 

[Diehard]

Well I don't disagree with frodo, as far as the proper way to pipe it. But I would still venture a guess that the neighbor's troublesome sink trap is not properly vented.
But in any case, you can throttle down the pumps flow. Have you reconfirmed this yet with the manufacturer?

 

[frodo]

here is the code, what you need to ask yourself is ''why'' the pipe ''shall be located not less than 10 pipe diameters''

the pump tie in location is causing the sewage gas and bubbling coming up into the kitchen sink of the neighbors

The neighbor may very well have a venting problem or lack of a vent, because of your pump
have to accommodate him. He is under no obligation to re pipe or add a vent to his sink


"Short cycling" is a term that usually refers to the frequency of pump cycles, not the length of their duration. In other words, you want your pump to start/cycle as infrequently as possible regardless of how long it actually runs each time it does cycle. To make your pump's run times as long as possible, set your float switch so your sump volume will go from nearly full to nearly empty each time the pump runs.
Just like with a vacuum cleaner, a pump motor does less work and even draws a little less power when its flow rate is partially restricted. Throttling a water pump too greatly can cause it too overheat when there is little water passing through to take motor heat away, but a little restriction could lengthen the run time of your pump if you want it to run longer each time it runs ... and globe valves are best for that kind of thing. But, I do use a quarter-turn ball valve to restrict the flow in my hot water recirculation line. The issue with ball or gate valves for throttling is erosion. Globe valves are designed for that purpose and will last longer.

The more water it pumps during each cycle, the fewer times it will start/cycle ... and that is a key factor related to pump life. How long the pump runs each time it cycles is a secondary issue.

 

[Diehard]

Yup!
I was going to ask why 5 feet when the code calls for 10 pipe diameters, but felt it wasn't relative to the main issue.

Basically, AC pump motors are NEMA rated for so many starts per hour. This is due to the extra heat generated in the motor on every start operation. Typically the larger the motor the more critical it gets. Fractional HP motors not as critical.


You have to remember that the pump manufacturer designed their system and motor selection based on the intended application and has stated the pumps operating capabilities.

I believe adjusting the float level(if adjustable) would have a much lesser impact on recycle time than adjust the discharge head it's pumping against. Those pump packages don't hold a lot of water.

But you are totally correct in saying the fewer times it starts per period of time the better.

So if the problem resulted in causing the addition of a valve, it should in turn reduce the flow rate and subsequent starts per hour.

Thought this video was interesting. This guy installed the same pump. Not only does it show the same incorrect piping arrangement, he demonstrates how short the pump runs. Of course this is due to the minimal head he is pumping against.

 

[frodo]

thing is, throttling the pump would not be necessary if the piping configuration was correct
the pump is pumping water past the 2nd floor drain pipe
this causes a vacuum as the water goes by. note, a gravity drain does not fill the pipe, the top acts as a vent
the pumped line closes off the vent and causes suction.

the reason for the pipe to enter down stream and 20'' is to negate the suction on the other piping

 

[Diehard]

Oh, so it is the vacuum/suction effect that is causing, "sewage gas and bubbling coming up into the kitchen sink". I would have thought a properly vented sink trap would negate any effect on the sink trap with that condition.

And to think all this time I thought it may have been excessive pressure.

 

[frodo]

the pump being upstream of the upstairs take off is causing the pumped water to enter the pipe of the neighbor
simply because it is being pumped.
can you get your head around that?
you are aware that a pumped line and a gravity drain line do not act the same?
at the beginning of the pump cycle he will get bubbling up from the pumped water
at the end of the cycle he likely gets a dry trap

the fix, as it is spelled out in the code
is to pipe the pump line into the drain line down stream of the sink
it calls for a minimum of 10 pipe diameters, I over compensate, by installing it 5'
i have never had an issue or call back by piping it at 5'
after the piping is corrected the op should not need to throttle the discharge

 

[Diehard]

Sorry buddy but I was being a bit sarcastic.

First you say, "this causes a vacuum as the water goes by. note, a gravity drain does not fill the pipe, the top acts as a vent the pumped line closes off the vent and causes suction.

Then you say, "the pump being upstream of the upstairs take off is causing the pumped water to enter the pipe of the neighbor"

Why do I feel like I'm talking with my wife?

I never disagreed with the piping fix and I say that in post #13.

I was always just trying to answer what the original poster was asking.

 

[frodo]

slow down and stop trying to over think it

As i show in the illustration, [arrows represent air] in the beginning cycle of the pumping
the water is pushing air down the pipe in front of the water
so you have pressure , water spitting up in the sink
as the pumped water passes the opening of the upstairs sink
you will then get suction.
so yes, you get both suction and pressure


remember, the pipe is not gravity draining, it is full of pumped water
therefore the venting system does not apply,

I understand you are just answering the op's question.
the answer is yes the discharge line can be throttled
BUT, why? does it need to be throttled? the answer to that is because it is not piped as per code.
so the correct answer to the op, is, correct the piping configuration and the throttle will not be necessary