Question
I'm writing from Tulsa, OK where are lawn is fescue in the shade and bermuda in the sun.  We  recently had a full yard irrigation system installed.  We have always been under the impression that long, deep soakings every four or five days was the way to water the yard.  The installer is now telling us that 15min. per zone starting around 4:00am, every morning is better for a good looking, think lawn.  We have noticed that people in our neighborhood with sprinkler systems seem to be doing just that.  Any guidance you can provide would be very much apprecitated.  

Answer
Your sprinkler salesman doesn't know what he is talking about.
I have gone to the websites of some of the leading agricultural colleges in the country, and looked this up.
They ALL say a deep watering, and less often is the way to go, for the reason that a deep root system protects against heat and cold and drought damage.
Keep one thing in mind, the salesman doesn't necessarily know diddly about lawn care.
I was in ourside sales in one way or another most of my business career years. When I was in sales for another company, and when I owned my own company.
For me to seel something, I needed to know my product.
I was a salesman(woman), NOT a vloser.
To work for me, my personell had to be salesman, not closers.
MOST salesmen are  closers, and they look at the commission, and will say whatever they need to say to make the sale. I know this from the personal experience of working with and knowing many salesmen, and knowing what they will and will not do. that's whay these salesmen don't like to sell to another salesman, hey know they can't sell their speil, if it is not the right thing to tell.
The simple fact is, those sprinkler systems are the biggest waste of money there is, in my opinion.
You can't program them to water properly.
They are to seel and make a big commisxion from, not to use for your own personal use.
Check this question out with your County Agricultural Extension agent. Check it out with Oklahoma A&M.
With the shallow watering, the roots have to come to the surfce to get water. Go away for a week, and if it is hot weather, you could come home to a dead lawn. the roots cannot absorb enough water to sustain them for a longer period of time.
When the roots come to the surface to get water, they are more susceptable to the heat and cold damage, and can be killed. That is what causes your thatch buildup.
The roots die, trap more debris, and build up a layer of thatch, that will not allow ANY water to the roots.
You then either have to dethatch, or you lose a lawn. You will probably lose a lot of it anyway.
Then you have to replant or resod. why keep doing the same job over and over?
:eaving the water on 15 minutes, tou don't even wet the top inch very well.
Go by the salesman's house and look at his lawn. Look to see if he has one of those systems.
He either lied, or he doesn't know what he is talking about.
When I livesd in Tulsa, I had fescue and burmuda lawn. I had  a very thick, healthy lawn. I followed a seep soak and less ofter watering program.
Charlotte