We added an outdoor faucet at the back of our house last year. It's a sillcock quarter-turn frost-free faucet with a vacuum breaker on it. We tapped it off of a pex tube that went to the front outside faucet. Last year it worked fine with plenty of water pressure. When I turned it on this year, all I got was a very tiny stream of water coming out. Does anyone have an idea as to what might be wrong?