About 25 years or so ago I had underground sprinklers installed in my house and since the contractor said he had to call a plumber to install the required ball valve and backflow preventer shown in my pictures(I think that’s what you call this fitting) I offered to install these fittings myself and all worked fine for about 5 years and the contractor will come every Fall to blow the system dry. Then City Hall banned the use of these sprinklers for water conservation and I stopped using the sprinklers since. However every Fall I have to cut the water to outside two hose bibs I have to prevent water freezing. In the front hose bib shown in the picture here, I shut the ball valve from inside the house and then I open the drain valve inside the house + the one outside and let the water drain completely. The next day I shut off the exterior hose bib to prevent anything going into it but after a few days when I open that hose bib there is lots of water, with some pressure, coming out again. The picture you see of the exterior hose bib I had this valve closed last week and today when I took the picture I opened the valve and water splatter all over the wall and floor and its visible on the picture. Then the water will stop coming out and eventually will stop. I will estimate the water coming out is about 1/2 gallon. When the ball valve is shut and the sprinklers have been dead for years where all this water come from? [img]https://cimg4.ibsrv.net/gimg/www.doityourselft.com-vbulletin/979x734/2_interior_piping_188432403aed92d218549fdb82cac6cb6c4d1a2a.jpg[/img] [img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/979x734/3_interior_piping_3a99a3d31a0186e4d003d33e53a08a993452a628.jpg[/img] [img]https://cimg1.ibsrv.net/gimg/www.doityourselft.com-vbulletin/734x979/5_exterior_piping_69f3a8584c93eaf549925c32d5acfe78c0ca0f16.jpg[/img]

We recently removed a counter-top peninsula which had baseboard heat on the backside. I have moved the location of the baseboard to the opposite end of the kitchen, which made more sense to me anyways as it is colder on the exterior wall side. I tied back into the original location where the baseboard tied back into the main monoflow 1" pipe that feeds the entire system. I have added approximately 25-30ft of pipe with supply and return of the baseboard. I installed a baseboard elbow with vent/bleeder that I am not getting any air out of anymore, only cold water. Any help/suggestions would be greatly appreciated. Background: Navien 240 combi boiler with 2 zones; main floor and basement. Taco circulator for each zone. Expansion tank with 4900 series Taco air separator.