control knob delta ?

This is a slightly confusing question.

It's in the plumbing category
You talk of either the washer of a temperature control knob - or -
The temperature control knob of a washer (washing machine perhaps)

The flippant answer is of course - remove the old and fit the new - but you probably know this yourself.

The make and model of the equipment would help a lot - don't you think? Also the specific issue you're having with whatever it is.

Have another try
February 2015