Help with conditional formatting

[suprsnipes]

In cell A5 I am using the following formula to show a countdown display between two times.

=TEXT(B5-db!A1,"hh:mm")

How can I use conditional formatting to colour the contents of the cell if the countdown display is less than or equal to 15mins?

Regards,
suprsnipes

 

[AlphaFrog]

In cell A5 put this formula instead and then format the cell as hh:mm
=B5-db!A1

Then use a conditional formatting formula like this.
Cell value is <=TIME(0,15,0)

 

[suprsnipes]

Thank you