Heath-Zenith Wireless doorbells are garbage. In the past 3 years since I bought the first one, I have had to replace this doorbell 3 times. I bought one at Walmart for about $15. It lasted a year. I replaced the battery in the outdoor button, still it did not work. (The indoor ringer is 120V AC). I bought another complete set, and found the bell (indoor) was fine on my old one, but the outdoor button was dead. A few months later it was dead again, and a new battery did not fix it again. I was able to exchange it that time. Now, once again it's dead. It appears to be the button again. This time I contacted the manufacturer. They said that they would replace it if it was still in the one year warranty and I had the receipt. I cant find the receipt, so they refuse to assist me, even though they admit that it's probably defective.
After this much trouble, I dont even want another one, and will install a wired bell. DO NOT buy them, they are total trash. I should mention that the outdoor button is under a roof too, so it's not water getting into it. Just very poor quality (made in China) crap. The model number is SL 6151-RX-A
Mark