Thermostatic control without tearing out wall

Hi, I had a vacuum breaker on a hose bibb that literally *sprayed* water several feet out around the spigot when the water was turned off and the hose drained (with a trigger sprayer at the end). The other hose bibbs around the house all have VBs on them that drip profusely (as the should) when the water is turned off and the hose is drained, but the water simply falls directly to the ground rather than spraying outward. I bought a new VB and installed it, but this time nothing happened when I turned off the water and drained the hose. Went to a different big box store and bought another one but it turned out to be the same brand/model. I installed it anyway and the same thing happened -- nothing. I doesn't drip one drop of water when the supply is turned off and the hose is drained. Since two of them did this I'm thinking they can't both be defective, but every other hose bibb VB I've installed in the past drips when the water is turned off, and when I put the old one back on, it still sprays water when the water is turned off and the hose drained, just like it did before. Are these new ones really defective or has something changed such that they don't drip the water like the old ones? Thanks for any insight anyone can provide. I want to make sure my home's water supply is protected, especially when I've got a hose-end sprayer with yard chemicals attached!

I have an older propane fire pit. I had been having issues getting it to light. I replaced the regulator hose this afternoon and it seemed to solve this issues getting it to light. I checked for leaks and did not find any in the connections, however, I did find a leak that occurs on the control valve (See Pic) when the gas line to the burner is open or when lighting. I have not been able to find a replacement value. The fire pit is about 10 years old and the manufacturer cannot direct me to a suitable replacement. Is there a way to "rebuild" or fix the existing valve? Or, should I even be concerned about the leak? As I stated, the valve does not leak when the propane tanks is open and burner control is in the off position. It only leaks when the gas is flowing to the burner. I know propane pools, so I don't want to do anything that would put us at risk. I would hate to have a flash explosion while sitting around the fire pit after 15 minutes. As information, the fire pit is on our back screened in porch which is a concrete slab[ATTACH]78008[/ATTACH]