Originally Posted by: Mystic-B 
I'm wondering if someone might be able to help me sort this out. We have a kenmore Ultraquiet, unknown model# in our rental home. We've lived here for four years and the previous tenants used the same dishwasher for an approximate two years before us. We'd had trouble with it leaving dusty grit in the rinse cycle for some time- and they sent a handy man to look at it. He replaced the chopper and our problem was dealt with for a time. One day last week I did a load and the water would not drain. I took it apart thinking it might have a clog. Nothing was on the internal side. We took apart the drain line - nothing. We checked the check ball... Nothing we could tell was blocking, but the drain was not engaging.
As a last ditch effort before calling the landlord, I put Drano Max Gel in the line hoping it would help. The man at wal mart said it was fine and safe to use in dishwashers. Nothing was listed on the label as contradictory, so I used it. No such luck. I went ahead and called the landlord and the handyman came out and said it sounded like the pump itself went out and he'd have an actual service man come do the official diagnosis. This particular model has the pump and motor attached so you have to essentially replace both- and in some cases its cheaper to get a new dishwasher.
My landlord told me today that the service man told her (he has not been out to see it yet) that because I used drano- I've ruined the pump and there is no way to know if it was broken before hand. I'm claming 'foul' because I already knew the pump was not engaging. It was not even turning on to TRY to drain. My question is--- would the use of drano gel really ruin a pump? Can it be determined that it was broken before drano was used?
Thanks in advance,
M
This was a while back, but this is also one of the first likely google results from any search about drano and dishwashers. So in the interest of helping people, I'll add my 2cents.
Drain cleaner is mainly lye (sodium hydroxide, caustic soda). The following myths and facts should be noted when considering using it in a dishwasher.
1. You wear rubber gloves when you work with lye. It doesn't hurt seals. Rubber being hurt by lye is a MYTH
2. You use glass or plastic bowls to mix lye for soap making. It doesn't hurt plastic. Plastic being hurt by lye is a MYTH.
3. Your plumber will not work with you easily if you pour lye into a clogged dishwasher because it is a risk of hurting your HOUSE and being liable for the damage. Lye water is dangerous is a FACT.
The issue is not whether the dishwasher was damaged by the lye, the question is, can he get a bowl big enough under your dw to catch the drain water after he disconnects the clogged line? Or will it spill (yes probably), and now he has a spill of lye water, not just dirty water.
The resistance is because the situation is odd. Under a sink, he can get a bucket, but you can't fit that under a dishwasher. Logistics is the reason, not so much chemistry.
Of course, if you leave strong lye solution in anything that has some metal parts, it will eat those parts away. So the days and days you wait for someone willing to fix it are likely to hurt the METAL parts, but not the rubber or plastic. Worry more about the chopper and the stainless steel interior.
Stay cool. Actually the best time to use a DILUTE solution of lye in your dishwasher is when it is NOT clogged but just hard to clean. I mean, reasonably you can't get into the spray nozzles, so a caustic is the only way to clear them if vinegar doesn't work, and no it doesn't always work. Just use the shortest cycle and then run it a few more times to clear it out.
As the website says, this isn't "advice" as much as it is my opinion. But I haven't ruined one yet.
