Please clarify: http yellow when delayred is set? Or, what makes http yellow?

I have this default set:
0.0.0.0   .default.   # DOWNTIME=0:0000:0300 delayred=http:10

and servers that are monitoring three URL's  like so:

10.1.2.3   web1.example.com #  CLASS:webzone ssh apache
http://web1.example.com/url1.htm http://web1.example.com/url2.cfm
http://web1.example.com/url3.cfm


What I'm seeing is, with one URL going red with a timeout after 22
seconds, the http test is going YELLOW and then going RED ten minutes
later. Does delayred turn the test yellow? If not, why is this test
turning yellow? We want it to be RED.

What exactly determines whether an http test is red or yellow?

thanks Betsy