How to spec the right rooftop A/C unit to make sure it ... · How to spec the right rooftop A/C unit to make sure it delivers the performance customers expect. Red Dot’s R-6100

R-6100: Low-profile, high-performance applications

When it comes to operator comfort, two key selling points for

any vehicle are space and visibility. But big interiors and lots of

window glass add to the demands placed on another critical

comfort item: the air conditioner.

“As a trend, we’re seeing more spacious cabs and larger

windows in every type of vehicle we design for,” says Gary

Hansen, vice president of engineering at Red Dot Corporation,

a leader in heavy-duty mobile HVAC units and replacement parts.

“A rooftop A/C unit is ideal for bigger cabs because it can

deliver high-performance cooling without taking up valuable

interior space.”

Because it’s mounted on the cab’s exterior, a rooftop A/C unit

should be purpose-built to handle impact, vibration, and other

demanding operating conditions, Hansen says. He offers these

tips below to help you make the right choice.

How to spec the right rooftop A/C unit to make sure it delivers the performance customers expect.

Red Dot’s R-6100 is the ideal low-profile rooftop A/C unit

for commercial trucks and other on-highway equipment. It

produces a strong, steady stream of cool air—16,000 BTU/hour

and airflow of 265 CFM. At that rate, the operator can work with

the door open and still feel the effects of spot cooling.

Why it’s different: The R-6100 extends just 7.4 inches above

the roofline so it won’t interfere with bodies or other equipment

that may protrude over the cab. Beneath the sleek, roto-molded

housing is a tightly integrated package of components designed

for long life and efficiency. For example:

• Tube-and-fin coil construction ensures strong condenser

performance in dusty, dirty conditions. The copper tubing

is 0.022 inches thick, resulting in an effective, lightweight,

rugged coil.

• The sealed motor is a permanent magnet type with a slinger

ring and hubcap for weather protection. The condenser unit’s

fan is aluminum with a heavy-duty spider and riveted blades.

• A high-capacity, spring-loaded receiver drier helps stop

moisture from compromising the performance and life

of the system.

It also saves space inside. The R-6100 ceiling plenum houses

the controls for the blower and thermostat as well as a cab air

filter yet protrudes barely 1.5 inches below the headliner.

Applications: Heavy and medium-duty trucks and other on-

highway equipment cabs that require a low-profile rooftop unit.

Ordering information: See page 473.

No rooftop mobile A/C unit has a more proven track record than

the Red Dot R-9727. It delivers 22,000 BTU/hour of cooling and

airflows of 320 CFM (evaporator) and 850 CFM (condenser),

and its durability and performance are best-in-class for rugged

on and off-road environments.

Why it’s different: Some units may look like the R-9727 but

only the real thing will deliver the performance and durability

equipment owners expect.

The R-9727’s robust components are housed in a heavy-

gauge steel casing that’s gusseted and reinforced to increase

its structural integrity. “Little things add up to a more durable,

reliable unit,” Hansen says.

For example, Red Dot use a sealed, long-life evaporator and

condenser motor with a slinger ring and hubcap for protection

from weather and dust. Instead of using several small hinges

for the service panel, the R-9727 has one continuous stainless

steel piano hinge. The result is a stronger joint that contributes

to the rigidity of the housing while ensuring accessibility to the

components when service is necessary.

New for 2011: Red Dot will offer a hydraulic compressor

upgrade kit for the R-9727 that attaches to the back of the unit,

the perfect solution when you can’t run the compressor directly

from the engine.

Applications: Mining, agriculture, construction.

Ordering information: See page 474.

R-9727: Robust and rugged rooftop A/C

Red Dot’s R-9976 hydraulic compressor gives you flexibility on

applications where an engine-mounted compressor isn’t the

best option for a rooftop A/C unit.

The R-9976 direct-drive hydraulic compressor requires no belts

or clutch and minimizes A/C hose length - ideal for cranes and

articulated equipment where the cab and engine are far apart.

Available in displacements of 5 and 9.3 cubic inches.

Ordering information: See page 68, 93, 476.

R-9976 Hydraulic Compressor: Flexibility for tough installations

470 Contents Index

Replacement Parts & Service: Align your Preventative Maintenance (PM) schedules

Scheduled preventive maintenance is the best way to make sure an A/C system is effective and efficient. Start by synchronising

your HVAC parts replacement with engine lube intervals. The accompanying chart shows you how.

“Most HVAC PM intervals involve a three-month, six-month or annual inspection,” says Hansen. “When a vehicle is in for scheduled

service, follow the recommended inspection schedule for the compressor and belt-drive system, condenser, receiver-drier,

expansion valve and evaporator.”

Cool, clean, reliable air is vital to operator safety as well as comfort. Promote regular preventive maintenance and quality all-makes

parts and you’ll generate HVAC parts and service business all year long.

It’s A/C season all year

The best way to cut down on A/C-related repair costs is to incorporate inspections into your overall PM routine.

Here’s where to start:

Maintenance Interval (Months) 3 6 12

1. Annual System Maintenance

Perform manifold gauge check. If gauge pressures indicate low refrigerant charge:

1) Recover and recycle refrigerant; 2) Perform system evacuation and leak test; 3) Recharge system •

2. Compressor & Belt Drive System

Once a month, engage the A/C and run the system for 5 minutes to lubricate the compressor and

verify that the condenser (engine) fan engages and disengages

Check discharge line (warm or hot to touch) •

Check suction line (cool to touch) •

Inspect face of clutch hub for signs of slippage (heat discoloration) •

Check clutch working voltage and current draw •

Inspect shaft seal for oil or dirt (indicates leakage) •

Confirm clutch pulley alignment with crankshaft drive pulley •

Inspect idler pulley for bearing wear (looseness) •

Inspect compressor belt for glazing or cracking •

Check belt tension •

3. Condenser

Clean dirt and bugs from condenser fin area (more frequently if necessary) •

Inspect fins and straighten as necessary •

Inspect tubes for dents and stains (indicating leakage) •

4. Receiver Drier

Replace annually or after the system has been opened •

Check sight glass for signs of moisture or bubbles •

Check inlet line from condenser (warm to touch) •

Check temperature of drier canister (warm to touch) •

5. Expansion Valve

Check inlet (liquid) line from drier (warm to touch) •

Inspect refrigerant charge head for damage and leakage •

6. Evaporator

Clean dirt and bugs from evaporator fin area (more frequently if necessary) •

Check temperature of copper inlet plumbing tube behind expansion valve (same temperature as outlet tube) •

7. Other Components

Thermostat: Check for proper operation •

Air filters: Check for restriction; clean or replace as required •

Pressure switches: With manifold gauges installed, check for proper operation •

Water valve: With control panel temperature setting on full "cold," check valve for full closure and

adjust cable as needed•

Credit: Red Dot Corp.

471Contents Index

R9757 SERIES

R97570PRed Dot Rooftop Air Conditioner / Heater 12V

• Height: 292mm

• Width: 657mm

• Length: 857mm

• Weight: 61kg

• BTU’s: 25000 cooling

• BTU’s: 45000 heating

R9757024PRed Dot Rooftop Air Conditioner / Heater 24V

Part No. DescriptionRed Dot

Ref. No.

Page

No.

RD550491P Motor Dual Shaft 12V 73R4422 14


RD580920P Evaporator Blower Wheel CW 73R7200 22

RD580921P Evaporator Blower Wheel CCW 73R7210 22

RD447240P Condenser 77R0660 185

RD587474PCondenser Fan Assembly

12V 13”73R8652 262

RD587475PCondenser Fan Assembly

24V 13”73R8654 262

RD587901P Fan Guard Assembly N/A

RD227910P Evaporator Coil 76R6015 242

RD113790P Heater Coil 76R1860 334

RD568680P Block TX Valve 71R8301 495

RD572720P Receiver Drier 74R2546 448

RD577601P Water Valve Assembly 72R5220 N/A


Ref. No.

Page

No.

RD568330P High Pressure Switch 71R7075 393

RD536470P Resistor 71R1450 482

RD5453124P Thermostat 71R3200 582

RD566900P Relay 12V 71R1902 483

RD566930P Relay 24V 71R1904 483

RD569172P Control Cable Water Valve 72R9005 N/A

RD559280P Control Knob 71R4040 483

RD563951P Low Pressure Switch 71R6040 393

RD364010P Plenum Plastic Assembly 477

RD41232P Mode Switch ON - OFF - ON 71R0200 481

RD500710P Fan Switch ON - OFF - ON 71R0400 482

RD538460P Louvre Assembly 4.5” 72R3200 368

657mm

857mm

292mm

857mm

472

Rooftops

Contents Index

188mm

326mm

642mm

257mm

790mm

R6100 SERIES

R61000PRed Dot Rooftop Evaporator Assembly 12V

• Height: 188mm

• Width: 642mm

• Length: 790mm

• Weight: 20kg




Ref. No.

Page

No.

RD211890P Cover Assembly Outer 477

RD572970P Fan Blade 73R8100 268

RD571290P Motor 12V 73R0542 7

RD5712924P Motor 24V 73R0544 12


RD545830P Pressure Switch Trinary 71R7550 392

RD447380P Condenser Coil 77R0620 N/A



RD566900P Relay 12V 71R1902 483

RD566930P Relay 24V 71R1904 483



Ref. No.

Page

No.

RD573120P Blower Wheel CCW 73R6300 22



RD573110P Blower Wheel CW 73R6350 22


RD209610P Roof Seal 477

RD212970P Plenum Gasket 477


RD559280P Knob 71R4040 683

RD536460P Switch 3 Speed Rotary 71R1150 481

RD212900P Plenum Diffuser Assembly 477

RD559370P Recirculating Filter 78R5300 222

473

Rooftops

Contents Index

R9727 SERIES


• Height: 264mm

• Width: 624mm

• Length: 768mm

• Weight: 47kg




Ref. No.

Page

No.






RD546400P Pressure Switch Binary 71R7000 392

RD571290P Motor 12V 73R0542 7

RD5712924P Motor 24V 73R0544 12

RD435080P Fan Blade Condenser 73R8110 268




Ref. No.

Page

No.

RD310638P Blower Wheel Evaporator CW 73R6101 22

RD310639P Blower Wheel Evaporator CCW 73R6151 23


RD536460P Switch 3 Speed Rotary 71R1150 481

RD559280P Knob 71R4040 483

RD209610P Roof Seal 477

RD212900P Plenum Diffuser Assembly 477



RD538605PComplete Blower Evaporator

AssemblyN/A

264mm

320mm

624mm

257mm

768mm

474

Rooftops

Contents Index

R9777 SERIES

R97770PRed Dot Rooftop Heater / Evaporator Assembly 12V

• Height: 200mm

• Width: 760mm

• Length: 940mm

• Weight: 30kg


• BTU’s: 45000 heating

R9777024PRed Dot Rooftop Heater / Evaporator Assembly 24V


Ref. No.

Page

No.



RD585830P Blower Motor Assembly 12V 73R5552 2

RD5453124PThermostat Side &

Bottom Mount71R3200 522


RD545830P Pressure Switch Trinary 71R7550 392


RD592241P Water Valve Cable Operated 72R5285 338

RD590763P Condenser Fan Assembly 24V 73R8644 262


Ref. No.

Page

No.

RD585831P Blower Motor Assembly 24V 73R5554 3

RD566900P Relay 12V 71R1902 483

RD566930P Relay 24V 71R1904 483

RD598330P Switch Rotary 3 Speed 71R1160 481

RD589670P Switch Rocker 71R0840 482


RD594370P Resistor 12V 71R1402 482

RD594450P Resistor 24V 71R1401 482

760mm

940mm

200mm

940mm

475

Rooftops

Contents Index

RD539050PFilter Assembly

To suit R9727, R9757, R9800, R9777,

Universal Applications

• Ref. No. 78R5000

• Diameter: 260mm

• Length: 457mm

• Complete with all fittings

to mount directly to rear of unit

SPX012Flexible Air Tube

• 73mm x 10m

RD542960PIn-line Booster Pressuriser

• Ref. No. 73R9202

• 12V

• Inlet: 100mm

• Outlet: 75mm

• Weight: 3kg

RD542961PIn-line Booster Pressuriser

• Ref No. 73R9202

• 24V

RD564271PRubber Elbow

• Ref. No. 78R5500

• Inner diameter: 75mm

R99761PTo suit Hydraulic Axial Direct Drive

• The perfect solution when you can’t run the compressor directly from the engine

• GPM: 1.1 - 6.3

• Displacement: 9.3 cu.in.

SPX0443” Pre-cleaner

To suit RD539050P

RD554320PReplacement Filter Element

• Ref. No. 78R5210

RD5109720PDrive Coupler

RD5124830PNeoprene Spider

RD5112090PElectronically Piloted

Hydraulic Control Valve

• Ref. No. 72R9904

• 24V

• Normally open

RD5112100PConverts RD5112090P

from 24V to 12V

• Ref. No. 72R9912

476

Rooftops

Contents Index

Documents

How to spec the right rooftop A/C unit to make sure it ... · How to spec the right rooftop A/C unit to make sure it delivers the performance customers expect. Red Dot’s R-6100