Luc
Member
Just a few questions on domestic hot water recirculating system. Our building is 13 years old and we have experienced several leaks in the copper tubing of the hot water recirculating system.
The circulating pump is a grundfos UP15-18 SF. The output of the pump is in 3/4'' copper tubing and connects to the 75 gallon water heater.Then from the water heater there are 3 supply lines of 1'' that run in different direction of the building. The 3 supply lines at some point are reduced eventually to the 1/2'' return lines that all connect on the same 3/4'' line at the input of the pump. The building is 40' x 100' with 3 stories.
Over the years, we had several water leaks in the 90 degree elbows and tees on the 1/2'' return lines just before they connect to the 3/4'' line. We installed a bypass on the pump to slow down the flow of water in the supply lines since we thought that there might be a corrosion problem due to the high velocity of water and the fast changes of the water flow. Even with a portion of the flow going through the bypass of the pump we still got some leaks in the return lines.
Would anyone know if this is a problem due a bad design? Should the return piping be 3/4''? Would it help to install a smaller pump? Will a smaller pump give enough head to the system? Our water pH is 7.4 so I don't think acidity is a problem.
Kind regards,
Luc
The circulating pump is a grundfos UP15-18 SF. The output of the pump is in 3/4'' copper tubing and connects to the 75 gallon water heater.Then from the water heater there are 3 supply lines of 1'' that run in different direction of the building. The 3 supply lines at some point are reduced eventually to the 1/2'' return lines that all connect on the same 3/4'' line at the input of the pump. The building is 40' x 100' with 3 stories.
Over the years, we had several water leaks in the 90 degree elbows and tees on the 1/2'' return lines just before they connect to the 3/4'' line. We installed a bypass on the pump to slow down the flow of water in the supply lines since we thought that there might be a corrosion problem due to the high velocity of water and the fast changes of the water flow. Even with a portion of the flow going through the bypass of the pump we still got some leaks in the return lines.
Would anyone know if this is a problem due a bad design? Should the return piping be 3/4''? Would it help to install a smaller pump? Will a smaller pump give enough head to the system? Our water pH is 7.4 so I don't think acidity is a problem.
Kind regards,
Luc