Immobilize Insinkerator disposal (lock rotation)?

[pasadena_commut]

Installed a new Insinkerator disposal today. After it was rotated all the way "up the slope" on the mounting flange it is still possible to rotate the body of the disposal, which is good, because that is needed to line it up with the top of the J trap. But it is also bad, since there seems to be nothing but friction and force on the outlet tube to keep it from moving. Is there some trick to lock it so that it cannot rotate once it is in the desired position? (The instructions which came with it don't mention anything.)

The previous disposal, from the same company, was making some unpleasant noises but kept working. What finally caused it to be swapped out was that the end of the outlet, the part going into the T for the other sink, cracked and started leaking. It was thin chromed brass, like the rest of the pipes. When it was all taken apart the tip of the lateral from the other sink was also cracked at its tip where it went into the T. While those pipes were old, I think what may have happened is that the slight twist when the disposal turned on and off flexed the tips of those two pipes back and forth until they cracked. Admittedly not a huge problem since it took 25 years to fail, but better no motion at all.

In other news, the wire inside the armored cable from the wall to the disposal, was found to be shedding its insulation on the disposal end. I could pull it apart with my fingers. It is possible that this wiring is as old as the house, built in 1957. Anyway, Home Depot didn't have anything like that on the cut to order spools (only needed 3 feet of it), but they did have this:

https://www.homedepot.com/p/Southwi...-CU-Lighting-Flexible-Whip-55082415/203387031
It worked really well. It was also kind of expensive - win some, lose some. Cut it in half (roughly) and the fitting on one end snapped perfectly into the metal plate for the electrical box. There was no specific grounding screw inside the box but there was an unused mounting screw, so that was used for the green wire. Almost certainly not code, but heaven only knows how this box is grounded, almost nothing in the house is. The disposal says to install a strain relief for the cable, which it does not supply nor does it suggest any part numbers. The cable in the drawing doesn't even look armored, more like lamp cord. Hoping to get lucky, the fitting from the unused end of the cable was transferred over, but it was too big for the hole in the disposal. For once I had guessed that this might be a problem and got one of these ahead of time:

https://www.homedepot.com/p/Halex-3...e-Metal-Conduit-FMC-Connector-91100/100212971
which screwed into the supplied hole in the disposal and nicely clamped the metal armor on the cable. It might not be quite the right choice, but it is certainly better than just leaving the cable dangling out of the hole suspended by the wires.

 

[breplum]

There is a detent/raised bump as the flange up-ramps and you have to get the rotating part to go over the bump. I use channel locks to bring it over the bump to lock.
We never use armored cable for disposals. Upgrade to a electrical outlet and only use a wire pigtail or most-often, just buy with the pigtail already installed.

 

[pasadena_commut]

How does one maintain the "angle" of the disposal, so that the outlet remains lined up with the other plumbing, while also rotating it to move the bump?

Changing this electrical box to an outlet is likely to be a big can of worms. Only the hot and neutral are present inside the box, yet the metal box is grounded. Somehow - inside the wall on the outside of the box. Probably there is armored cable running from the breakers and that is clamped onto the outside of the box. Or it could be bonded to a cold water line (galvanized) which is about 6 inches away. I cannot see what is holding the box in place (no screws or nails are visible on the bottom, top, or either side). There is a single brass screw head visible near the middle in the back, touched it with a screwdriver and it wobbled around like it was loose in a hole. The other two screws are just holding in a sort of wire clamp plate, one at the top (used) and one at the bottom ( empty, used as the ground screw). Given all that, making up a replacement armored cable seemed like the safer path.

 

[havasu]

If you have a brass screw in a metal box, this would be your best ground placement. Them referring to supporting the wire is for the 6' piece, but since you are only using 3', no support is necessary, provided both ends are secured properly.

 

[pasadena_commut]

If you have a brass screw in a metal box, this would be your best ground placement.

That was my first thought. But the screw head is flush with the back of the box and touching it with a screwdriver it just flops around, like it is in too big a hole, or a hole which isn't threaded.

 

[havasu]

A self tapping screw works as well.

 

[pasadena_commut]

Today the new disposal was run while I held it (lightly, with rubber gloves). It was operated with water running and starting with an empty or full sink. In both cases I could not feel or see any macroscopic rotation when it started, while it was running, or when it shut off. What I could feel was quite a lot of vibration, and I could not determine if that vibration was a tiny amount of rotation (less than a millimeter where I was holding it) or if it was vibrating in some other manner (like the case flexing in and out, or the unit precessing). The vibration can be felt all the way down to the bottom of the trap, and out along the lateral to the other sink, so it is definitely vibrating the pipes and not limited to just the disposal.

Not having ever done this particular "measurement" on a sink before, is this level of transmission of the vibration from a disposal typical?

 

[GReynolds929]

Yez

 

[JIMMIEM]

Does your model have 3 screws that apply tension to the flange to keep the disposal from rotating after you have gone over the 'humps'?

 

[pasadena_commut]

There are 3 screws that are threaded through the lower "3 ramp" piece, which pull on the locking ring and via that on the "cup" in the bottom of the sink, by pressing on the top of the flange which is on the bottom of the sink. Those screws were fully engaged before the unit was lifted up and rotated onto the flange.

Not sure about the "humps". Poking around with the tip of my small finger ahead of the tabs which ride up the ramps it feels flat for a couple of millimeters, then there is narrow ridge (maybe 1 mm wide and about as high), and then a couple more millimeters of ramp, after which the tab would fall off the end of the ramp. The tabs feel much wider than the region after the ridge.

Could not find a single picture of the position the tab is supposed to be in on the ramp when fully installed. Did find this thread:

https://diy.stackexchange.com/quest...ink-disposal-come-loose-from-the-locking-ring
where the ridge I described is just barely visible in the first picture at about 70% height and about 10% width from the left edge. My fingernail can catch that ridge going in either direction, it really feels more like a stop than something a flange is supposed to go over. If I used enough force to go over that I would have thought the tab would have just skidded right off the edge of the ramp, which is pretty flat there, and the whole unit would fallen off its mounting flange. If the tabs did go over that then I'm pretty sure if one felt up underneath the flange at the end of a ramp part of the tab would be felt partially overhanging the end of the ramp. Or if my "finger gauge" is off, maybe the tab ends close to parallel with the end of the ramp?

 

[breplum]

I've installed more than 1,000 ISE disposals since 1974 and never had a problem. Perhaps you are missing the rubber gasket. Without pics, can't tell.

 

[pasadena_commut]

I think I see the problem.

After watching many installation videos I found this one:



which at around 9:00 shows the loop on the lower flange (where the special tool or a screwdriver goes in to rotate it) being rotated until it collides with the corresponding mounting flange for the big screws on the top flange. That is the key point. The tab riding up the ramp apparently does go over the little ridge mentioned above, but cannot fall off the end of the ramp afterwards because these two pieces of metal (in each of 3 sets) collide and stop further motion.

Mine is currently configured a little tighter than the video shows at around 8:37. So the lower flange needs to rotate a little farther.

Reviewing the ISE instructions step 24 does say to "go over the ridge", and I missed that. (In my defense, I had to use a magnifying glass to read the text and see the fine details in the drawing.) However, the picture in the instructions does not quite correspond to that in the video, as in the video there is no space visible between this pair of metal parts, whereas in the drawing there is about as much space as the width of the loop.

 

[havasu]

Yes, you rotate until it locks in place.