I have a building that I am getting ready to troubleshoot some issues. I have a Chiller with one loop pump and 2 Air Handler s with 3-way control valves. The pump is a constant speed pump and the piping loop from the chiller to the pumps is relatively short (80-100 feet of 4" total). The supply side of the pump pushes the water through the AHU 3-way valves. Th chiller is outside on the ground level, I have one AHU on the ground floor and one AHU on the second floor. The pump is located on the second floor. I have several issue's I want to figure out to troubleshoot the system.
(1) I know the pressure drop through the chiller barrel is lower than what Trane recommends. They have butterfly valves on the inlet on outlet of the chiller, but when I try to modulate each one I see no significant rise in Barrel DP.
(2) I am going to check the flow against the design pump head to make sure that everything is ok within my pump curves
My questions from an engineering standpoint are:
(a) I know that when filling a system, the old school way I was taught was to check the measurement to the highest point, figure that static head and add 4 psi. Based on that theory, is that the best way to determine if I have enough water in my system.
(b) What would cause me to not maintain the DP through that barrel? Could it be low water, incorrect piping size, pump location.
I think this was s design build by a previous contractor and they did not engineer it correctly. I know that Trane chiller designers want to take the present value of flow through the barrel (assuming its within chiller min/max) and double that to figure if there is enough system capacity. So if I have 200 GPM through the barrel they want 400 gallons of system water capacity based on pipe size and length. But I cannot reach my minimum flow and I am not sure with the pump on the second floor what my static head should be at the ground level and is that the best way to determine water capacity.
Sorry to ramble and duplicate info/questions. me=confused
(1) I know the pressure drop through the chiller barrel is lower than what Trane recommends. They have butterfly valves on the inlet on outlet of the chiller, but when I try to modulate each one I see no significant rise in Barrel DP.
(2) I am going to check the flow against the design pump head to make sure that everything is ok within my pump curves
My questions from an engineering standpoint are:
(a) I know that when filling a system, the old school way I was taught was to check the measurement to the highest point, figure that static head and add 4 psi. Based on that theory, is that the best way to determine if I have enough water in my system.
(b) What would cause me to not maintain the DP through that barrel? Could it be low water, incorrect piping size, pump location.
I think this was s design build by a previous contractor and they did not engineer it correctly. I know that Trane chiller designers want to take the present value of flow through the barrel (assuming its within chiller min/max) and double that to figure if there is enough system capacity. So if I have 200 GPM through the barrel they want 400 gallons of system water capacity based on pipe size and length. But I cannot reach my minimum flow and I am not sure with the pump on the second floor what my static head should be at the ground level and is that the best way to determine water capacity.
Sorry to ramble and duplicate info/questions. me=confused
