Valves are modeled as links (like pipes) in the steady state / EPS engine and as such the engine supports the notion of minor losses in fully open links. This is to account for such things as bends and fittings, or just the physical nature of the link (element). However, note that the minor loss for a valve only applies when the valve is fully open (inactive) and not restricting flow. For example, a flow control valve (FCV) that has a higher set flow than the hydraulics provide for, is fully open and not limiting the flow passing through. In this case the computation will use any minor loss on the FCV and calculate the corresponding head loss. If on the other hand the set flow of the FCV was low enough for the valve to be required to operate, the head loss across the valve is determined by the function of the valve. In this case the head loss would be the value corresponding to the function of reducing the flow to the set value of the FCV.

The purpose of several of the valve types included in HAMMER CONNECT is simply to impart a head loss in the system, similar in some ways to a minor loss. One example here is the Throttle Control Valve (TCV). The TCV supports a head loss coefficient (or discharge coefficient) that is used to determine the head loss across the valve. It is important to note, however, that the head loss coefficient on the TCV is actually different from a minor loss in the way it is used by the computation. The minor loss applies when the valve is fully open (inactive) and the head loss coefficient applies when the valve is active. This same principle applies to other valve types such as General Purpose Valves (GPVs), Pressure Breaker Valves (PBVs) and Valves with a Linear Area Change (VLAs), the only difference being that GPVs use a headloss/flow curve, PBVs use a headloss value and VLAs use a discharge coefficient, instead of a head loss coefficient, to define the valve's behavior when it is in the active state.

In some cases a minor loss coefficient sounds like it could be a duplicate of another input value, but the way in which it is used in the computation is not the same.