Carrier 42GWC Hydronic Cassette: Slim, Quiet Comfort for Low Ceilings

Shallow false ceilings, noisy indoor units, and uneven airflow cause many complaints in modern buildings. Designers often have only a few centimeters above the ceiling grid. Occupants expect cool, quiet rooms with no drafts or hot spots. The Carrier 42GWC Hydronic Cassette handles all three challenges in one compact, ceiling-mounted package.

This guide is for MEP engineers, consultants, contractors, facility managers, and property owners. It explains what this cassette is, how it performs, and where it fits best. You’ll find complete technical data for models 003 to 008, a sizing and application table, control options, maintenance tips, and answers to common buyer questions.

What Is the Carrier 42GWC Hydronic Cassette?

The 42GWC is a four-way, ceiling-concealed cassette that cools and heats rooms using chilled or hot water from a central plant. It sits above the false ceiling, and only a slim return air grille and supply louvers remain visible.

In technical terms, it is a fan coil unit. It has no compressor and uses no refrigerant inside the room. A fan pulls room air through a water coil, and the coil either removes or adds heat. As a 42GWC Hydronic Cassette Fan Coil Unit, it connects to chillers, boilers, or heat pumps through a two-pipe water circuit.

Every fan and coil unit follows the same basic principle. What sets this model apart is its 298 mm height, four-way air throw, very low noise, and built-in drain pump.

Key Facts at a Glance

• Height: Only 298 mm, ideal for limited ceiling voids
• Air distribution: Four-way, for even room coverage
• Noise level: As low as 29 dB(A) on compact models
• Cooling capacity range: 3,200 W to 8,700 W
• Heating capacity range: 4,900 W to 13,500 W
• Coil: 7 mm lanced fin coil in an “L” configuration
• Condensate: Integrated, sound-insulated drain pump
• Motor options: Standard AC or optional BLDC (EC) motor
• Controls: 0–10V thermostats, two-way and three-way valves, RS485 Modbus

42GWC Hydronic Cassette Fan Coil Unit Technical Specifications

The table below lists the full performance data for each model. Airflow and noise values appear as high / medium / low fan speed.

Model	Airflow (m³/h)	Cooling Capacity (W)	Heating Capacity (W)	Power Input (W)	Noise Level [dB(A)]	Water Flow (l/min)	Coil Rows	Water Connection (inch)	Dimensions (mm)	Unit Weight (kg)
003	540 / 430 / 350	3,200	4,900	36 (AC) / 14 (DC)	35 / 32 / 29	9.5	2	3/4	575 × 575 × 298	16.5
004	680 / 540 / 440	3,700	5,800	48 (AC) / 25 (DC)	40 / 35 / 31	11	2	3/4	575 × 575 × 298	16.5
005	850 / 680 / 550	5,800	9,000	50 (AC) / 22 (DC)	35 / 31 / 27	17	2	1	825 × 825 × 298	37.0
006	1,010 / 810 / 660	6,600	10,200	60 (AC) / 28 (DC)	37 / 33 / 29	19.5	2	1	825 × 825 × 298	37.0
008	1,360 / 1,080 / 880	8,700	13,500	102 (AC) / 50 (DC)	45 / 40 / 35	25	3	1	825 × 825 × 298	39.6

How to Read the Data

The range splits into two body sizes. Models 003 and 004 use a compact 575 × 575 mm chassis that weighs just 16.5 kg, which suits standard 600 mm ceiling grids. Models 005, 006, and 008 use a larger 825 × 825 mm body for higher loads. All five share the same 298 mm height.

Power input shows two values. The first is the standard AC motor. The second is the optional DC (BLDC) motor, which draws far less electricity at the same duty.

Takeaway: You can keep one slim ceiling profile across an entire building and simply step up the model size for larger rooms.

Key Features That Set the 42GWC Apart

Compact 298 mm Design

At only 298 mm tall, the unit fits ceiling voids where many cassettes can’t. That matters in retrofit projects, apartments, and offices where beams, ducts, and sprinkler pipes already crowd the space above the ceiling.

Four-Way Air Distribution

Air leaves through four louvers in four directions. This spreads conditioned air evenly across the room, reduces drafts, and removes the hot and cold spots common with one-way wall units.

Quiet Operation Down to 29 dB(A)

An optimized centrifugal fan moves air smoothly, while anti-vibration motor pads stop noise from traveling into the ceiling structure. Model 003 runs at 29 dB(A) on low speed, and model 005 drops to 27 dB(A). That’s quieter than a typical library, so the unit suits bedrooms, consultation rooms, and meeting spaces.

High-Efficiency 7 mm Lanced Fin Coil

The coil uses 7 mm tubes with lanced fins arranged in an “L” configuration. Lanced fins break up the air boundary layer, and the L shape increases the coil surface inside the same compact casing. The result is stronger heat transfer without a taller unit.

Integrated Condensate Drain Pump

A high-performance drain pump is built in and wrapped in sound-insulating material. It lifts condensate water away quietly and reliably, so you don’t need a separate external pump or steep gravity drain falls.

Washable Return Air Filter

The return air grille holds a washable filter. It traps dust and keeps air circulation fresh, and you can clean it without tools or replacement costs.

Where This FCU Fan Coil Unit Fits Best

The 42GWC works best in buildings served by a central chilled water plant, where each room or zone needs its own quiet, independent control. The table below gives a general guide. Final selection should always follow a proper heat load calculation.

Model	Approx. Cooling (TR)	Typical Spaces	Why It Fits
003	~0.9 TR	Hotel rooms, private offices, clinic rooms	Lowest noise, light 16.5 kg body
004	~1.05 TR	Bedrooms, small meeting rooms, boutiques	Compact body with more airflow
005	~1.65 TR	Open offices, apartment living rooms	27 dB(A) low speed with high capacity
006	~1.9 TR	Retail floors, restaurants, lobbies	Strong airflow for busy spaces
008	~2.5 TR	Large offices, showrooms, conference halls	3-row coil for the highest load

Commercial and Residential Applications

• Offices and IT companies: Quiet, even cooling that supports focus and comfort at workstations.
• Retail stores and malls: Discreet ceiling units that keep sales floors clear and uncluttered.
• Hotels and serviced apartments: Low noise levels and individual room thermostats for guest comfort.
• Hospitals and clinics: Hydronic cooling keeps refrigerant out of patient rooms, and washable filters support hygiene routines.
• Premium residential spaces: Villas and luxury apartments get a clean ceiling finish with near-silent operation.

Low Ceiling Applications

Many buildings have ceiling voids under 350 mm, especially older properties and towers with tight floor-to-floor heights. A 298 mm unit leaves space for hangers, pipe connections, and maintenance access. This often removes the need to drop the ceiling, which protects room height and interior design.

Comfort Benefits for Occupants

Good comfort depends on more than temperature. The 42GWC improves three things people notice right away:

• Even temperatures: Four-way airflow reduces stuffy corners and cold spots.
• Low sound levels: Quiet fans support sleep, calls, and conversation.
• Fewer drafts: Air spreads gently along the ceiling instead of blowing straight at occupants.

Hot water heating adds year-round value. In winter, the same unit delivers up to 13,500 W of heat on model 008.

Energy Efficiency and the Optional BLDC Motor

How the BLDC Option Makes This Fan and Coil Unit More Efficient

The optional brushless DC (BLDC) motor offers stepless airflow modulation. Instead of three fixed speeds, the fan adjusts smoothly to match the actual room load. This brings three main gains:

1. Lower electricity use: DC models draw 48% to 61% less power than AC versions. Model 003 drops from 36 W to just 14 W.
2. Precise temperature control: Gradual fan changes hold the set point more closely.
3. Quieter part-load running: The fan runs slowly most of the time, which cuts noise further.

Across a hotel or office tower with hundreds of cassettes running long hours, these savings add up to a real reduction in yearly operating costs.

Controls and Compatibility

The 42GWC integrates easily with both simple room controls and full building management systems.

• Thermostats: TMS710/720, TMS810, and THT420 series
• Electric control valves: Two-way and three-way options to suit variable or constant flow water systems
• BLDC motor: Compatible with 0–10V thermostats for stepless speed control
• Room controllers: Compatible with RS485 Modbus systems for BMS integration

With Modbus connectivity, facility teams can monitor and adjust each unit centrally, set schedules, and cut energy waste in empty rooms.

Maintenance Advantages

Easy upkeep keeps lifetime costs low. The washable filter sits behind the return air grille and comes out in minutes. The built-in drain pump removes the extra failure point of a separate pump. Because the unit uses water instead of refrigerant in the room, there are no gas leaks to trace inside occupied spaces.

Simple routine: Clean the filter every one to three months, check the drain pump and tray twice a year, and inspect the coil and valves during annual servicing.

Common Specification Mistakes to Avoid

• Sizing by floor area alone. Use a full heat load calculation that includes glazing, occupancy, and equipment.
• Ignoring valve choice. Match two-way or three-way valves to your chilled water pump strategy.
• Skipping the BLDC option. In long-hour buildings, the energy savings often justify the upgrade.
• Poor access planning. Leave ceiling access for filter, pump, and valve servicing.

Why Choose This Model

Why Choose the Carrier 42GWC Hydronic Cassette Over Other Terminal Units

Factor	Wall-Mounted Unit	Ducted Concealed Unit	42GWC Cassette
Visibility	Visible on wall	Hidden, with grilles	Discreet ceiling panel
Air distribution	One direction	Depends on ductwork	Four-way, even coverage
Ceiling space needed	None	Ducts plus unit	Only 298 mm
Drain solution	Gravity drain	Often external pump	Integrated pump
Install complexity	Low	High	Moderate

A wall unit takes up wall space and throws air in one direction. A ducted fan coil unit needs extra ceiling depth for ductwork and diffusers. The 42GWC sits between the two, with a hidden look, even airflow, and simple installation.

Workman Services: Your FCU Fan Coil Unit Supplier and Installer

The right product needs the right installation partner. Since 2006, Workman Services has delivered HVAC&R and fire fighting solutions across residential, commercial, industrial, healthcare, office, and retail projects.

Our designers, sales engineers, and certified technicians cover the full project cycle:

1. Consultation and load calculation to select the correct model
2. Supply of genuine units, valves, and controls
3. Installation including piping, drainage, and electrical work
4. Testing and commissioning of airflow, water flow, and controls
5. Maintenance and after-sales support

Our project experience includes FCU supply, HVAC, and firefighting work at Haseens, Giga Mall, plus projects at Nishat Galleria Mall and several Dolmen Mall outlets. We also supply and install chillers, AHUs, VRF systems, TFA units, and ducting, so your cassettes connect smoothly with the wider system.

With branches in Lahore, Rawalpindi, Faisalabad, and Abu Dhabi, we support projects across Pakistan and the UAE. Call +92 306 4410583 or email info@workmanservices.com.pk for a quotation.

Frequently Asked Questions

What is a fan and coil unit?

It is an indoor terminal that uses a fan to move room air across a coil filled with chilled or hot water. It cools or heats the space without a compressor in the room.

How much cooling does the 42GWC Hydronic Cassette Fan Coil Unit provide?

Cooling capacity ranges from 3,200 W (about 0.9 TR) on model 003 to 8,700 W (about 2.5 TR) on model 008.

Is this FCU fan coil unit suitable for low ceilings?

Yes. Every model is only 298 mm tall, which makes it ideal for shallow ceiling voids and retrofit projects.

How quiet is the 42GWC?

Noise drops to 29 dB(A) on model 003 and 27 dB(A) on model 005 at low fan speed.

Does it need a separate condensate pump?

No. A sound-insulated, high-performance drain pump is built into the unit.

Which thermostats are compatible?

TMS710/720, TMS810, and THT420 series thermostats work with the unit. BLDC models also support 0–10V control.

Can it connect to a building management system?

Yes. Room controllers are compatible with RS485 Modbus systems for central monitoring and control.

What is the difference between a fan coil unit and a split AC?

A split AC uses refrigerant and its own outdoor compressor. A hydronic FCU uses water from a central chiller or boiler, which suits large buildings with many rooms.

How often should I clean the filter?

Clean the washable filter every one to three months, depending on dust levels and operating hours.

Final Thoughts

The Carrier 42GWC Hydronic Cassette combines a 298 mm profile, four-way airflow, sound levels as low as 27 to 29 dB(A), and an integrated drain pump in one practical package. With an optional BLDC motor and Modbus-ready controls, it delivers comfort and efficiency for offices, hotels, hospitals, retail spaces, and premium homes.

Planning a chilled water project? Contact Workman Services today for a model selection, load calculation, and project-specific quotation.