I applied through college or university. I interviewed at Knowles Mechanical
Interview
Managers are very knowledgeable of the field and some still work covering calls. Thoroughly explained benefits and possible disadvantages to field work. They do ask technical questions to judge your experience level.
Interview questions [1]
Question 1
When plumbing an island drain in a kitchen and you can’t have a stack or mechanical vent, how would you accomplish the venting?