Today I arrived on site: AHU Hydro Lines: Returned to address multiple issues. Hydro Setup: Found an incorrect setup for the Heat/DHW and AC system zone. Corrected the hydro setup. Installed a backflow check valve. Installed a zone valve. Upon arriving at this property, The client was not on the property. The homeowner of the proposal was contacted to contact the tenant. The tenant arrived at the property an hour later. I proceeded to verify the system. Prepare and clean the work area. I proceeded to drain the water from HWH and the hydro coil. I proceeded to dismantle the AHU hydro lines. I proceeded to install the new back-flow check in the correct position. I proceeded to install the zone valve in the correct position. Wire and I made all the connections and adjustments necessary to conclude with the repair. Start the system in heat mode, the system operated correctly. I ran the DHW, the hot water is operating well. I concluded with the necessary repairs and adjustment