Yes,Conquer can be used insides of a Chapin Multi-Purpose Sprayer.
No, Conquer is not labeled for yellow jackets. We would recommend using Wasp-Freeze. This comes in an aerosol can and travels up to 15 feet away. It will also not be heavy and does not need to be mixed with water. It is labeled for yellow jackets as well as other various flying insects. Please let us know if you have any additional questions.
We apologize but there are no replacement parts available for the Chapin Multi-Purpose Sprayer 48 oz. (1002).