Garbage disposal and drain problem/questions.

This is for a friend of mine who just called me.
He said he replaced a kitchen sink garbage disposal for someone. He is not a plumber. The person called and said the sink wasn't draining and the original garbage disposal was apparently bad and was making tons of noise. So, he put in a new one.
Before the changeover, the sink would barely drain at all -- with or without the garbage disposal running.
Now, with the new garbage disposal installed, the sink still barely drains at all -- except that, with the garbage disposal running, it drains perfectly. He tried snaking out the drain line past the garbage disposal but he didn't encounter any clogs and that didn't change anything.
He is left with a new garbage disposal in place and a sink that won't drain unless the garbage disposal is running.
Additional info:
1) He said it's a "Badger" (maybe) garbage disposal -- I am about to Google that and look for an installation manual; and,
2) He said something about a plastic pop-out piece (I think for the dishwasher drain) that he popped out.
But, is there something else with a new garbage disposal that needs to be removed or done so the sink drains properly without the garbage disposal having to run?
Any other thoughts or suggestions?
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Rather strange. A few things come to mind:
Did he look at the pics that show the permissible heights for the disposal versus the outgoing drain line, the trap, bottom of the sink, etc?
Some chance it might have something to do with venting. Is that sink line properly vented? Vent line clear?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Tom-
Short Answer:
Are other drains "upstream" or downstream off the ktichen sink slow? My best guess...vent problem. Go up on the roof & look down the vent with a flashlight.
Long Answer:
Since the drain was slow prior to the garbage disposal change out, the garbage disposal is not the cause of the drain problems. IMO the new unit (working unit) is helping the drain work by "pumping" the water down the drain under a bit of pressure hence my suggestion that the drain has a vent issue.
How far did he snake the sink? Did the snake have a cutter / business end of any appreciable diameter?
The installation was a simple R & R...I doubt he made a mistake.
The "plastic pop-out piece" is supposed to be popped out if there is a dishwasher drain line to be attached.
"is something else with a new garbage disposal that needs to be removed or done so the sink drains properly without the garbage disposal having to run"
No. Drain function should be independent of disposal.
The way I see this situation; 1) check & clear vent as needed 2) if vent is clear & sink is still slow, the drain line needs to be snaked
good luck, let us know how it works out
cheers Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 8/25/2012 10:27 AM, TomR wrote:

I think you answered your own question. Drain was slow with old disposer and still slow with new disposer. What is the constant?
Disposers do encourage draining. Occasionally I may do something where there is a quantity of water in the sink. Flipping on the disposer will make it drain significantly faster.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, IF there is debris in the garbage disposal, that is true. If the disposal hasn't been run in a while then you can have some debris in it that will reduce the flow. Once you run it for a few seconds, the debris is gone and then the water runs out full speed whether it's on or off. That is very different from what the OP is reporting.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Saturday, August 25, 2012 7:27:30 AM UTC-7, TomR wrote:

The most common kitchen sink problem in these situations is a grease buildup. The only way to determine that is to take some part of the kitchen sewer line apart and look inside it or stick a sewer camera in it. Harbor Freight sells the cameras fairly cheap.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

"He tried snaking out the drain line past the garbage disposal but he didn't encounter any clogs and that didn't change anything. "
>Lots of

There should be only one trap.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks everyone for all of the responses and suggestions. They all made sense to me.
Here's some follow-up information, but unfortunately I doubt that we will know what the problem will turn out to be. The reason is that after I passed on what everyone suggested, my friend decided that he was going to call the homeowner and suggest that the owner have a regular plumber come out and fix the problem.
When he told me more about what was going on, he added that this is a condo unit in a condo complex. He also said that when he originally tried using the snake, he couldn't get it to go too far in -- maybe only 5 feet or so. He thinks that maybe the snake encountered a Tee joint or something like that and he couldn't feed it past that. So, he thinks that a plumber with the right type of snake on a machine will be able to clear out the line. Or, if it is a vent issue, and since (I now know) it is a condo unit in a condo complex, a plumber would need to try getting to the vent from the roof or whatever.
At least he now knows that the new garbage disposal is not the source of the problem, and he just charged them a minimal fee for putting in the new disposal (only $40 in labor, plus the cost of the new disposal that they had already bought). He didn't charge them for his efforts at trying to snake out the drain line etc.
He does do other work for the owner and other members of the owner's family who have other properties. So, if he does hear back what the outcome is after they have a plumber come out, I'll pass that information on by posting it here.
Thanks again. The suggestions did help, including helping my friend know that the problem may be out of the scope of his ability, or may be something that required a different type of snake etc. than what he has.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.