Today I arrived on site Issue Identified: No hot water and a buzzing noise in the boiler system, affecting both heating systems and DHW. Problem: Determined the DHW circulate pump was not functioning. Resolution: Replaced the DHW circulate pump. Current Status: The system is now up and running. Upon arrival at the property. The housekeeper gave me access to where the boiler room is. I proceeded to verify the system. I found that the circulate pump was doomed. I proceeded to disassemble the defective CP. I proceeded to install the new CP covered by the warranty. I proceeded to make the connections and adjustments necessary to conclude with the repair. I proceeded to bleed the indirect tank area. I completed the repair successfully. I started the system and monitoring for about 10-15 minutes. The system began to operate normally. The new Cp worked correctly on this occasion. The DHW began to heat up normally. Water ten set up to 140 at the stat control of the indirect tank.