During Ayambil / Navpad Oli, boiled water (uṣṇapāni) is normally taken only in a fixed daytime window, not the whole 24 hours.

In most Jain maryādā (especially Shwetāmbars):

• Start time:

- Either from sunrise, or - 48 minutes after sunrise (this is quite common – ask your guru / local sangh which rule they follow).

• End time:

- Up to sunset only. - After sunset, for Ayambil Oli, people usually keep chauvihār (no food, no water) or at least no water after sunset as stated in their pachkhan.

So, in practice your pachkhan might be like:

• “I will take only boiled, filtered water from sunrise (or 48 minutes after) till sunset; no water after sunset.”

Important:

• Fix the exact hours when you take boiled water, and follow your local sangh / guru’s guidance, because small details (sunrise vs +48 minutes) can differ by tradition.
• The night before starting Ayambil/Oli, it is considered better to already be in tivihār or chauvihār (no food, and often no water, after previous sunset).

You can read more about Ayambil practice here