constrained washer drain

[dlas]

Awkward situation here. Our Amana washer drains into a drain line that isn't quite up to snuff. It drains faster than the water can exit the drain. No, the drain isn't clogged. We've has a plumber come in to clean it out and inspect it. Something odd about the pressures in the drain line. So what do we do? I t occurred to me that if I could just slow down the washer drain outflow a bit, it would all be fine. So I'd like to put a half-inch hole on the one-inch drain line to do that. Is that going to damage the pump? I've worked with impeller pumps before, and my understanding is that they aren't really bothered too much by that. Can anyone speak from actual experience on this? I'd like an answer based on facts.

[16345Ed]

Making hole smaller will increase pressure. You have a plumbing drain problem and need a different plumber. 

[dlas]

The drain is clean. We've gone down there with a drain video camera. The different plumber will just say we need to do demolition work to replace the entire drain line. Not an option. The issue is whether the increased pressure will cause washer pump failure.

[Guest]

I don't have an answer about your idea but I do wonder if the drain issue is caused by not having a vent on the drain line?

I'd guess your drain line in 1.5"?

 

[dlas]

I think the question comes down to discharge cavitation, and my reading is that this gets dangerous when the discharge pressure is an order of magnitude higher than it should be. Reduction of the outlet size by a factor of two or three isn't going to do that. Also, I understand that when you get cavitation, the pump will make a lot of noise. I did some experimentation with restricted outlets, and didn't hear any.

Re vent on the drain line, that's a fair point. I do have one, but no one has ever established that it is really open. Needs to be checked. That could certainly slow the flow if air pressure is building up in the line.

[Guest]

Perhaps the vent for the drain is not setup correctly. A proper vent exits above the roof. 

You may have an inline cheater vent similar to what's shown in the picture. I have two that were not installed by me. They have poor performance. 

The drain line that put washing machines are hooked to has a proper above the roof vent. We have two washing machines with two drains that converge to the same 4" drain in the basement.  We've never had an issue with both washers draining at the same time or the shower running or any combination of that. 

Has your drain always been a bad performer or is this something new?

Personally I don't think your idea can create any issue but I would suggest you have your drain hose attached to something solid so it can't work it's way out of the drain pipe. 

 

[dlas]

As far as I can see, it's just a straight shot from the P-trap below the washer drain to the roof. Nothing on top of the pipe on the roof. But maybe there is something buried in the pipe. This problem is something new, but the washer is new, and the pump in this new washer may just be a faster pump. Yes, I am taking GREAT CARE to make sure a restriction in the outlet port doesn't get shot down the drain. I put together a 3/4" PVC tube, with a 1/2" hole drilled in an endcap that is glued on to it. For security, I drilled a hole through the end cap and put a thick copper wire through it. If the glue comes undone, that'll hold the endcap on. I have now actually tried this, and it seemed to work fine, with no drain overflows, and no unusual noises. Fingers crossed.

 

[Guest]

Well what I was meaning about the drain hose and securing it is that the increase of velocity of the water exiting the drain hose into the drain pipe could very well cause the drain hose to come out of the drain pipe. 

With mine there is a hanger attached to the drain hose where it curves to hook onto the drain pipe; on that holder I put a screw through the holder and into the box that surrounds the water connections. 

I'm certain your new washer doesn't have supersonic pumping ability; there's something wrong with your drain. It could be the diameter is too small which would not be a code-compliant drain, clogged vent, or very likely you don't have enough downward slope of the drain pipes. There's just too many variables that I can't physically see but I can tell you that your plumber should have been able to identify the issue very quickly when it wasn't a clog. Drains are simple. 

I can only imagine how much the plumber charged you for all that. 

 

[evaappliance]

Anytime you restrict the flow you will shorten the life of the pump but also it will stress the whole machine , not to mention if it is a new enough Amana that it locks the lid when in use , you may get long drain codes,  16345ed is right 

[Nathaniel Peterson]

IMO you need to get your drain line addressed. I'm not a plumber but know that Amana washer pumps are slow compared to a Speed Queen and your drain, if correctly draining should be able to drain without overflowing.

[dlas]

12 hours ago, evaappliance said:

Anytime you restrict the flow you will shorten the life of the pump but also it will stress the whole machine , not to mention if it is a new enough Amana that it locks the lid when in use , you may get long drain codes,  16345ed is right 

As I said, my reading is that pump life gets shortened with drain restriction because of discharge cavitation, and that is important only for seriously restricted drains. The key point is that discharge cavitation makes NOISE as the cavities implode, and I'm not hearing any noise. It's sort of handwaving to say that flow restriction shortens pump life. If you can point to a design engineering article that says that explicitly, with regard to modest restrictions, I'll take notice. It's also well understood that bleach will ruin a water pump, but it takes a lot of bleach.

Also, it's true that this drain pipe doesn't have much downward slope. It's embedded in the slab, and runs for about 30 feet on the level. That's why replacement would involve demolition. As I said, the drain has been inspected by video, and there are no blockages (though it is a very old drain that has some corrosion).

As to error codes, those are kind of irrelevant. The problem isn't with the washer, but with the drain. Drain time for the washer is just a few minutes, which is well under the 8 minutes that would result in a long drain time error.

[evaappliance]

7 hours ago, dlas said:

The problem isn't with the washer,

Right , but you just made it a problem with the washer when you modified the drain hose with a restriction.  Hope it works out for you 

[dlas]

Well, that's the question I'm asking here. Not at all clear it is a problem, and I don't hear a lot of experience in the matter.

[Guest]

The lack of downward pitch in the drain seems to be the one and only real issue here. 

I'm confused as to why it would be buried in a slab, but I'm not that familiar with slab houses; but I am curious how you know it doesn't slope if it's buried. I'm sure it doesn't, just curious. 

I know you're more concerned about your  restricted flow idea. I can't offer anything on that other than give it a try.  If you get poor performance then you'll know. 

You still need to fire that plumber if he didn't advise you that you don't have proper slope on the drain pipe. 

[evaappliance]

29 minutes ago, Dr. Horshenschwartz said:

I can't offer anything on that other than give it a try.  If you get poor performance then you'll know. 

 

At this point, with fixing the drain not being an option, this is all he can do 

[dlas]

In these parts, we don't have basements. Limestone makes basement excavation demolition work. When they pour the slab, the drain pipe is embedded. Standard procedure. I know the level where it goes in,and I know the level where it comes out, and they aren't all that different. But yes, maybe in this 70 year-old house they just didn't anticipate powerful washer pumps. As noted, I have tried putting a half-inch orifice on the washer drain pipe. It works. No over-fill. Also, no funny noises from the pump. So I am assuming that the job is done. I am surprised that there isn't any specific advice about the effect of partial blockage on washer drain pumps. Everyone says NO! DON'T DO IT!!! but no one seems to have any real evidence to back up that warning.

[Nathaniel Peterson]

41 minutes ago, dlas said:

In these parts, we don't have basements. Limestone makes basement excavation demolition work. When they pour the slab, the drain pipe is embedded. Standard procedure. I know the level where it goes in,and I know the level where it comes out, and they aren't all that different. But yes, maybe in this 70 year-old house they just didn't anticipate powerful washer pumps. As noted, I have tried putting a half-inch orifice on the washer drain pipe. It works. No over-fill. Also, no funny noises from the pump. So I am assuming that the job is done. I am surprised that there isn't any specific advice about the effect of partial blockage on washer drain pumps. Everyone says NO! DON'T DO IT!!! but no one seems to have any real evidence to back up that warning.

It says in the installation guide that the washer drain can't be hard piped and has to have an air gap. I don't understand what kind of evidence you want. We're appliance techs not plumbers. We just go by the install instructions. We're just trying to help with the part we know about. I know you can siphon water back into the washer without an air gap. I know if the drain hose is on the floor it can siphon the water out of the washer as it fills. If you make the pump work harder by reducing the drain it'll pull more amps reducing the lifespan of the pump. You sound like your pretty competent at doing stuff so go on repair clinic and put in your model number and order yourself a pump. You already said fixing the drain isn't something you want to do so that's really your only option. Good luck!

[evaappliance]

6 hours ago, Nathaniel Peterson said:

I don't understand what kind of evidence you want.

I am reluctant to say anything else about this but here goes,  sure it will work for a while , what he isn’t factoring in is the water also has lint out of the clothes being washed in it, that restriction is going to be stopping up with that lint , may take a little while but it’s going to happen. We as techs have seen this happen many times over the years, but nobody wants to just listen to us , they need proof or evidence that what we are saying is right . Customers listen to everyone else on the planet but when our answers are not what they want to hear they challenge us, the words ( just don’t do it ) is not good enough. 

 

6 hours ago, Nathaniel Peterson said:

If you make the pump work harder by reducing the drain it'll pull more amps reducing the lifespan of the pump.

Yep !    

[Guest]

2 minutes ago, evaappliance said:

I am reluctant to say anything else about this but here goes,  sure it will work for a while , what he isn’t factoring in is the water also has lint out of the clothes being washed in it, that restriction is going to be stopping up with that lint , may take a little while but it’s going to happen. We as techs have seen this happen many times over the years, but nobody wants to just listen to us , they need proof or evidence that what we are saying is right . Customers listen to everyone else on the planet but when our answers are not what they want to hear they challenge us, the words ( just don’t do it ) is not good enough. 

 

Yep !    

I had envisioned a 55 gallon drum mounted above the drain opening for the washer to discharge into unrestricted. That drum would have a 3/4" drain hose that would go into the drain pipe and gravity drain from there.  Just as easy to flop the drain hose out the window I suppose.

[evaappliance]

24 minutes ago, Dr. Horshenschwartz said:

I had envisioned a 55 gallon drum mounted above the drain opening for the washer to discharge into unrestricted. That drum would have a 3/4" drain hose that would go into the drain pipe and gravity drain from there.  Just as easy to flop the drain hose out the window I suppose.

Along that line of thought I have had many customers to have a big utility room sink by the washer to do what you are talking about,  sink fills up and drains at its own pace .  But we’re not plumbers lol !

[empirical_tuna]

I have a slow washer drain problem in my 70+ year-old house. I think the drain line is cast-iron pipes. The pipes have built up some scale, and lint from the washer discharge has caught on that and exacerbated the problem.

My long-term plan is to replace the drain line with plastic. However, in the short term, I did three things:

1. Added a basin for the washer drain hose that could accommodate the discharge while draining itself at a lower rate. Hacked together with a few rubbermaid wastebaskets, some shower drains, ABS pipe, and plywood. There wasn't room for a utility tub but my cheesy assembly gets the job done.

2. Hired a plumber to clean out the drain. He spent at least an hour with a motorized snake drawing out clumps of scale mixed with lint.

3. I began using metal mesh lint socks on the washer discharge hose. These are available online and secure to the end of the hose with included zip ties. With three people's laundry I need to replace them about once a week.

[evaappliance]

1 hour ago, empirical_tuna said:

Added a basin for the washer drain hose that could accommodate the discharge while draining itself at a lower rate.

now that will do the trick and not stress the washer !  excellent !