Existing Conditions
Hot water is presently circulated through the building by two xxx hp pumps. These pumps were originally designed to deliver a constant volume of water to the heating system. The perimeter hydronic systems have recently been retrofitted with two-way control valves. The two air handling units with heating (SF-1 and SF-4) still have three way mixing valves.
Most of the time, the pumps are creating a higher than required head at a low flow.
Retrofit Conditions
It is recommended that a variable speed drive be installed on one of the pumps, and the speed be controlled to maintain a constant pressure in the system. It is also recommended that the three-way mixing valves on SF-1 and SF-4 be changed to two-way control valves, in order to minimize the necessary pump speed.
Further Benefits
Application Details
Issues and Concerns
For greatest savings, most or all of the control valves in the system should be 2-way.
References
Analysis
Analysis text here