Tap on your Roadrunner account to open it up.
Tap on the menu key
Tap on Email Settings
Tap on EMail Delivery
Tap on Fetch Schedule and select the schedule you want, up to 4 hours. and close.
It will download your Email every four hours, if that is the one you request. You also have a 30 minute and a one hour fetch time. If you have Data push selected. It will push your Email thru to you every time a new one comes in.