Okay, let's clarify the VA calculation and the power factor situation for your Mitsubishi R454B ductless mini-split system.1. VA Calculation using MCA

You are correct in using the MCA (Minimum Circuit Ampacity) to calculate Volt-Amps (VA). MCA is specifically designed for this purpose. Formula

VA = Voltage MCA

Your Calculation

VA = 208V 12A = 2496 VA

Explanation

The MCA represents the minimum current the circuit needs to continuously supply to the unit, including the compressor, fan motors, and any other auxiliary loads during normal operation. Since it's a minimum continuous value, it's used to determine the minimum VA the circuit needs to handle. It accounts for the fact that the current and voltage may not be perfectly in phase (hence, the VA is usually higher than the actual power in Watts).

Therefore, 2496 VA is the correct Volt-Ampere (VA) value to use for sizing the circuit for this mini-split based on the provided MCA.Why MCA is used for VA, not Running Load Amps (RLA)

RLA typically represents the compressor's running current under specific conditions. It doesn't necessarily include all the other loads. MCA includes all loads running simultaneously. MCA is the minimum amount required to supply the unit, a safety factor is included within the value.

2. Power Factor What is Power Factor (PF)? Power Factor is the ratio of real power (kW) to apparent power (kVA). It indicates how effectively the electrical power is being used. A PF of 1.0 (or 100%) means all the power is being used to do work. A PF less than 1.0 means some of the power is reactive and not doing useful work. The Problem: Determining Power Factor without more information

Unfortunately, you cannot determine the exact power factor without more data from the manufacturer or by taking measurements. You would need to know the actual power consumption in Watts (W) or Kilowatts (kW) under specific operating conditions.

Reasonable Estimates and Considerations



Typical Range

Modern HVAC equipment, especially inverter-driven mini-splits, often have power factors in the range of

0.8 to 0.95. Inverters help to improve the power factor. Estimating Watts (W) if needed

If you need to estimate the power consumption in Watts for planning purposes (understanding that it is just an estimate), you can assume a power factor in that range. Let's say you assume a PF of 0.9: Watts = VA Power Factor Watts = 2496 VA 0.9 = ~2246 Watts

Important

Treat this as a rough estimate only! The actual power consumption will vary based on operating conditions, load, and the specific design of the unit. This estimate is primarily useful for understanding relative power usage compared to other appliances.

In Summary Your VA calculation using the MCA is correct: 2496 VA* You cannot determine the precise power factor without more information from the manufacturer or by taking measurements. Assuming a power factor between 0.8 and 0.95 would be a reasonable estimation for planning purposes, but it is not definitive. Flag for review