In Jain temple architecture and iconography, the direction in which the main idol (Moolnayak) of a Tirthankara is installed holds significance. Regarding Bhagwan Parshwanath as Moolnayak:

There is no absolute rule in Jainism that specifies a particular direction for installing the Moolnayak idol of Parshwanath. However, tradition and temple customs often guide this decision.

Common Practice:

• In most Jain temples, the Moolnayak idol—regardless of the Tirthankara—is generally installed facing east, as facing east is considered auspicious and associated with enlightenment and the rising sun.
• The direction may also be influenced by the temple's layout, the main entrance, and specific community (Shwetambar, Digambar) customs.

For Parshwanath Specifically:

• There is no scriptural injunction that Parshwanath's Moolnayak must face a particular direction.
• If you are referring to a specific temple or tradition, please provide the temple's name or location for a more precise answer.

Summary: In general Jain practice, the Moolnayak (main idol) of Parshwanath can be installed facing east, north, or another direction, depending on temple customs and architecture, but east is most common. There is no unique directional requirement for Parshwanath as Moolnayak in Jain scriptures.