[Xymon] How to shorten delay before purple alerts?

[Elizabeth Schwartz]

How can I change xymon to alert after a server has failed to report
for 15 minutes? We're finding that 30 minutes is too long a delay in
the production environment.

I see where you set purple delay for network tests and I see where you
can return it for individual tests, and I see where you can disable
purple. Is this a code change?

thanks Betsy