This post claims that putting vinegar in rinse aid reservoir of a dishwasher leads to damage (similar claims can be found here and here):
on newer dishwashers, the rinse aid compartments have rubber components that aren’t really compatible with acidic things like vinegar.
On the other hand, this dishwasher manual from 2005 explicitly allows the use on vinegar:
Alternatively, it is possible to use household vinegar with a max. 5% acid content
Also, the book of Advanced Cleaning Product Formulations, Volume 4 lists the following recipe for rinse aid:
- Deionized water - 30%
- Mazawet 36 - 55%
- Glycolic acid (57%) - 10%
- Isopropil alcohol - 5%
So, in essence:
- at least some dishwashers are not damaged by vinegar
- dishwashers compatible with common rinse aids are not damaged by weak acids
Is there any evidence of an actual dishwasher which got damaged by regular 5% household vinegar? So far I have only seen two statements, of which neither can count as evidence:
- My repairman told me not to use it - it basically means that anything home-made should be used at your own risk.
- I started to use vinegar and my dishwasher broke down - Correlation is not causation.