Powering a 120v Receptacle off of a 240v Circuit Breaker dedicated to an Appliance
Using a neutral for multiple hots creates what the NEC calls a "multiwire branch circuit". There are specific requirements , but generally the code requires all hot conductors of a MWBC be disconnected simultaneously with handle ties or multipole breakers. There is a requirement for MWBC's to only serve line to neutral loads unless fed by a multipole breaker, not just a handle tie. [2017 NEC 210.4(C)ex.2]

There are technical aspects that deal with types of appliances and percentage of circuits that fixed in place appliances are allowed to use that may render sharing the circuit with receptacles illegal. Specific requirements required in the installation and operating instruction are part of the UL listing, and may also render sharing the circuit illegal.