Upon receipt of a completed application and fee, the commissioner shall: (1) Issue and deliver to the applicant a certificate of registration as a mechanical contractor; or (2) refuse to issue the certificate. The commissioner may suspend, revoke or refuse to renew any certificate issued under sections 20-341s to 20-341bb, inclusive. The commissioner shall not revoke or suspend any certificate of registration except upon notice and hearing in accordance with the provisions of chapter 54.