When turning on the single control lever of the shower I usually turn it all the way to hot then adjust it to cooler temp... it is sticking on hot even when turned to cold... even feels as if it gets hotter... If I turn it all the way off.. then turn to warm temp it seems to work okay.. any suggestions? Delt faucet is about ten years old.

It is time to replace the cartridge, Delta faucets has life time warranty just call them at 800-345-3358 tell them that you have problem with the cartridge and they will send you a new cartridge for free no charge to you, good luck.
John