I am installing a new Bosch 300 series DW to an Insinkerator disposer barbed inlet.

The rubber fitting on the Bosch drain hose end is a difficult fit, I did all I could and the most I can insert is about 1/2" to 5/8" into the disposer end and tighten with a hose clamp. I am concerned a wrong bump would disconnect and the DW discharging into the sink cabinet.



I found this adapter that seems to be a much better fit, so use this one on the disposer end and connect the Bosch drain hose end to the other end?

Is the fitting on the disposer barbed? The barbs and a tight clamp would make the conection secure.

Did you heat up the end of the hose with a heat gun and use soap to get the hose as far on to the disposer fitting as possible? This would be to avoid using the adapter you are thinking of, which introduces an extra connection.and therefore an extra vulnerability.



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george, yes the disposer end is barbed. However, the depth of insertion is only 1/2" if that because inside the rubber hose connector is a step 1/2" in. So the hose clamp can only tighten around 1/2" of space, and I tried using my hand and can basically twist it off without applying a lot of force even with the hose clamp tightened to the point it started to cut into the rubber.



With the Insinkerator adapter I can push it all the way in on the disposer, probably 2" of connection with a hose clamp, and the other end to the Bosch drain hose also 1-1/2" of a "two step" overlap seems to be much more secured but like you said, it is an extra connection.

The Bosch drain hose has been trimmed at some point, excessively so if it has a step just half inch in. The adapter you have is a reasonable way out.

I keep an assortment of these poly insert fittings in my "dishwasher installation" box, along with short lengths of various size hoses just for these situations. Insert fittings available at the big box stores.




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Recently I replaced our 15 year old Bosch dishwasher with another Bosch dishwasher and had no problem connecting the new one to the existing airgap located on the sink. First connecting to an air gap is "best" and code in many areas and what I recommend doing.

From the air gap I then used the existing 7/8" dishwasher hose that was attached to the air gap. The airgap comes with 2 different sized connections. The small inlet size and the larger outlet size.

The adapter that George mentioned is what is needed if one isn't going to connect the dishwasher to an airgap and from that adapter 7/8" dishwasher hose is then used to connect to the disposer.

George this is a brand new Bosch dishwasher delivered last week and it's a brand new drain hose so it hasn't been cut short.

The only gripping and sealing of that connection is the width of the clamp over the barbs. As I see it, as long as the barbs are covered and the clamp installed, having a longer skirt without a clamp on it doesn't matter.

Yes and no. While the sealing is over the barbs, the extra hose over a barb gives extra pull-out resistance if tight fitting. Extra hose over fitting also makes the joint more resistant to sideways forces. This is why Sum was able to pull the hose off in spite of a very tight hose clamp.

steve even with the hose clamp tightened to the point of almost deforming the connection, I was able to twist and wiggle it off the barbed end quite easily. I used the adapter and it was much more secured.

Vic, I agree having an air gap is best but in this case I do not have one. I drilled a hole on the side of the cabinet right below the countertop to pass the drain hose through to give it a high loop.

After using the adapter like the one George showed now the connection is very secured.

I would suggest you secure your adapter fitting I’ve seen them bend,crack and shear off

A reduction of dia just 1/2 inch in on the Bosch hose suggests that the hose was really meant to be used on a smaller diameter barb that goes in, say, over an inch into the hose.