Todd Werner
New Member
We have a complicated plumbing system in our new home. There are two hot water tanks, the first being preheated by a geothermal system. There is also a recirculating loop with a taco pump that runs hot water from the powered hot water tank to the loop and returns it to the holding tank. The water returned from the loop gets reheated with waste heat from the geothermal systems.
It's very efficient, but the plumbers who installed it didn't consider pressure drops. The loop runs all the way to a semi-detached garage with a bathroom, so it is almost 300' long. But the cold runs are straight shots in the main house.
With the Taco pump and two showers going, the pressure drop in the hot water line is so great compared to the cold line that the second shower in line gets no hot water. What I think is happening is that the shower mixing valve (Delta) doesn't have enough hot water pressure. I estimate that by the time the hot water gets to the second running shower, after 300', that even without incorporating bernoullis principle due to the hot water being pulled past the second shower by the pump, the pressure drop must be at least 15psi.
Other than adding a 200' coil of pipe in front of the cold line, is there anything available that could decrease the cold side pressure when the system is flowing?
Thanks,
Todd
It's very efficient, but the plumbers who installed it didn't consider pressure drops. The loop runs all the way to a semi-detached garage with a bathroom, so it is almost 300' long. But the cold runs are straight shots in the main house.
With the Taco pump and two showers going, the pressure drop in the hot water line is so great compared to the cold line that the second shower in line gets no hot water. What I think is happening is that the shower mixing valve (Delta) doesn't have enough hot water pressure. I estimate that by the time the hot water gets to the second running shower, after 300', that even without incorporating bernoullis principle due to the hot water being pulled past the second shower by the pump, the pressure drop must be at least 15psi.
Other than adding a 200' coil of pipe in front of the cold line, is there anything available that could decrease the cold side pressure when the system is flowing?
Thanks,
Todd