Nomenclature Guide

This page is your go-to resource for understanding the model numbers and codes used in our products. Whether you’re looking to decode specifications or learn more about the industry, you’ll find everything you need to navigate our product lineup with ease.

A2L Transition Video

HX - CDX - HCX - UC - CL Series

NOTE:

Not all descriptors may appear for each model. See individual product specification documents for complete model number configuration options

Glossary

Section	Digit Codes	Description
Brand	F–First Co.	First Co. is a leading manufacturer of multi – occupant and commercial industry HVAC products.
Cabinet Options	0–Uncased / Std Multi-Position C–Cased with Panel	Ceiling fan coils can be enclosed or “cased” and accessorized with a ceiling access panel.
Heat Option	KW Heat Q–Standard Pump R–Hi-flow Pump W–Hot Water Coil HW–Without Pump	A higher kW in HVAC indicates more capacity for heating or cooling, but it must be matched with the specific requirements of the space and considered alongside efficiency ratings to ensure optimal performance and energy consumption. Water pumps and hot water coils are also available.
Metering Device	P–Piston V–Non-Bleed TXV	A Piston is used when the system is simpler, has constant load conditions, and cost-effectiveness is prioritized. A Non-Bleed TXV is recommended when the system experiences variable loads, requires precise refrigerant control, and energy efficiency is crucial. Please use product ratings to determine which metering device is appropriate.
Motor Type	0–PSC X–ECM	Permanent Split Capacitor motors run at a fixed speed and operate at full power regardless of the demand for heating or cooling. Electronically Commutated Motors are a type of variable speed motor with built-in inverters and microprocessors that adjust speed based on demand.
Refrigerant	A–R410A B-R454B C-R32 Z–Field Convertible Unit	Models can be compatible with multiple refrigerant options by using a non-bleed TXV, piston, and/or Refrigerant Sensor Kit.
Series	HX0, HXX, HXS HCX CDX UC0, UCX CLP, CLX	Name of product family
Unit Size	BTUHs	Air conditioners and heat pumps remove heat from the air inside a building and move it outside. HVAC Unit Size or capacity is measured in tons or BTUHs (British Thermal Units per Hour). This metric determines how much heat a unit can remove from a room within an hour. A one-ton unit can remove 12,000 BTUH.
Voltage	120 / 1Ph 60Hz 208-230 / 1Ph / 60Hz	Voltage is the electrical pressure that pushes an electric current through a circuit. Higher voltage indicates a more powerful pressure. Most HVAC systems use with 115 (120)V or 230V depending on size and capacity.
Options
Controls	0–Standard T–TimeDelay B–Standard Pump Control	The Standard Relay controls the operation of the blower fan, turning it on and off per the system’s call. A Time Delay Control will control the unit’s operation based on a set schedule. Standard Pump Control controls the temperature in the air stream utilizing hot water.
Sensors & Switches	0–None 1–Freeze Stat 2–Float Switch 3–Freeze Stat + Float Switch 4–DX Coil Sensor	A Freeze Stat is a temperature sensor that prevents coils from freezing by shutting down the fan, closing the hot water valve and opening the cold – water valve. A Float Switch detects the level of liquid in a drain pan and trips the electrical circuit shutting down the unit if necessary.