How to null fields in PostgreSQL?

Question

PostgreSQL

Good afternoon.
I am trying to reset the table fields using the command

UPDATE filters SET height_low=NULL|height_high=NULL WHERE chat_id=%s

gives an error message

psycopg2.ProgrammingError: column "height_low" is of type integer but expression is of type boolean
HINT:  You will need to rewrite or cast the expression.

It is necessary to convert integer to NULL, what can be done?