Plumbing Hydronic Zone Valve Cv Calculator

Calculate actual independently calibrated hydronic zone GPM/psi/specific-gravity Cv budgets, distinct from dimensionless valve authority and not nominal SI Kv, hardware or control safety.

Description

Cv uses US gallons per minute and psi with fluid specific gravity.

Cv uses US gallons per minute and psi with fluid specific gravity. It differs from SI Kv and dimensionless valve authority.^[1]

The returned values include Required zone valve cv. The How section below explains the calculation, input rules and interpretation.

When to use Plumbing Hydronic Zone Valve Cv Calculator

Use Plumbing Hydronic Zone Valve Cv Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. No hardware selection, authority calculation or control-safety approval is supplied.

Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.

How to use Plumbing Hydronic Zone Valve Cv Calculator and understand its results

Prepare measured flows, pressures, temperatures or inventories with consistent units. For catalog tools, use independently verified capacities at the stated operating conditions and supply the explicit design demand.
Enter observedZoneDesignFlowsGpm, callerTargetValveDropsPsi, callerMatchedFluidSpecificGravity using the field table and calculation rules, then run the tool.
Read requiredZoneValveCv. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
observedZoneDesignFlowsGpm	Observed zone design flows gpm	list of number	Required
callerTargetValveDropsPsi	Caller target valve drops psi	list of number	Required
callerMatchedFluidSpecificGravity	Caller matched fluid specific gravity	list of number	Required

Enter aligned nonempty nonnegative design GPM, positive target drops in psi and positive specific gravities. Return required Cv for each zone.

Cv_i=GPM_i×sqrt(specificGravity_i/dropPsi_i)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
requiredZoneValveCv	Required zone valve cv	list of number

json

{
  "input": {
    "observedZoneDesignFlowsGpm": [
      2,
      3
    ],
    "callerTargetValveDropsPsi": [
      1,
      4
    ],
    "callerMatchedFluidSpecificGravity": [
      1,
      1
    ]
  },
  "output": {
    "requiredZoneValveCv": [
      2,
      1.5
    ]
  }
}

Limitations and assumptions

No hardware selection, authority calculation or control-safety approval is supplied.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Plumbing Control Valve Authority Calculator: Valve authority compares a valve’s pressure drop with its total circuit drop at the same design flow. It is dimensionless. For a complementary task, use Plumbing Valve Choked Flow Check Calculator: Liquid choked-flow screening compares observed valve pressure drop with a pressure-recovery threshold. Absolute pressure is required for the vapor-pressure term.

References

Plumbing Hydronic Zone Valve Cv Calculator — tool.io

Similar or alternative tools

Plumbing Control Valve Authority Calculator
Valve authority compares a valve’s pressure drop with its total circuit drop at the same design flow. It is dimensionless.
Plumbing Valve Choked Flow Check Calculator
Liquid choked-flow screening compares observed valve pressure drop with a pressure-recovery threshold. Absolute pressure is required for the vapor-pressure term.