507.238.9051 507.238.9998 fax Email

RT200-600 Series Manual

RT200-600 Series


Cover image


Model 9027


Has smaller foot print than previous version. The heat developer is built into the heat pump which gives the system greater reliability and heat production at low idle. The heat developer uses the machines own hydraulic oil eliminating the need to remember to replace the oil periodically reducing the chance of pump failure and becomes less maintenance intensive. The condenser is custom built to be an iatrical part of the system allowing for best cooling capability, along with a condenser fan requiring zero electrical power to operate. All stainless steel housing provides for a lasting and corrosion free finish




Same simple controls as the first two revisions.


Check and clean the inside recirculation filter once a week. This filter is very important to keep in good shape. Without it the blower system would not able to pass air over the coils thus reducing its ability to cool or heat.

If Equipped

Clean the outside paper filter daily or as needed. This filter allows outside fresh air into the cab. Keeping this filter clean will greatly enhance the cab environment.


Clean out with air or water daily or as needed to remove dirt and debris from building up. Take special care not to damage coil fins. Inspect hoses and coil for wear or oil build-up since this may indicate a refrigerant leak in the system.

Compressor / Belt & Clutch

Check the belts for tightness as often as you would for any of the other belts on the machine. When replacing worn belts spin the compressor pulley to check for rough spots or a loose clutch. If either of these occurs, a service on the part should be performed as soon as possible.


Look for signs of leaks or wear on the hoses or other components. Move or relocate hoses that are rubbing or look as though they will be a problem in the future.
Listen for abnormal sounds from the electric motors, compressor or other parts of the heater air conditioner system. These could be signs of needed service.
Respond to early service warnings. It will help avoid bigger and more costly problems in the future. 

To operate the air conditioner/oil heater, use the following procedures:

A) Air Conditioning Mode:

  1. Start the machine and rotate the fan control to high, medium, or low speed.
  2. Set the master toggle switch to the a/c mode.
  3. Rotate the air conditioning thermostat to a desired setting. Rotating the thermostat clockwise will increase cooling.

B) Oil Heat Mode:

  1. Start the machine and rotate the fan control to high, medium, or low speed.
  2. Set the master toggle switch to the heat mode.
  3. Rotate the heat thermostat to a desired setting. Rotating the thermostat clockwise will increase heating.
  4. Increase the machine idle up to about 1000 rpm, or until there is adequate heat, and then return to low idle. If there is not adequate heating at low idle, increase the engine rpm until adequate heat is achieved.
  • Before starting the machine, turn off the heat mode at the blower unit and make sure the toggle switch on the hydraulic unit if in the “OFF” position.
  • Start the machine and allow to run for approximately 30 minutes with only the hydraulic motor turning. This allows the hydraulic oil to fill oil the heater circuit.
  • Check the direction of the motor rotation, it must be CCW as viewed from the port end of motor. If incorrect, switch supply and return lines around on the hydraulic motor.
  • Check to see if the hydraulic oil has filled the heat circuit. A Philips screw on top of the proportional relief valve acts as a bleed port. Back out the screw two to four rotations to allow any trapped air to escape. Note: The pump doesn’t have to be turning, the case drain from the rotating motor should provide enough pressure to fill heat circuit.
  • Turn on the heater inside the cab by turning the thermostat to maximum and flipping the mode switch to heat. Note: Operating the pump prior to filling the circuit with oil can cause damage to the pump.
  • On the hydraulic unit, flip the heat clutch toggle switch to “ON”. Listen for the pitch of the pump to increase. If it doesn’t, turn the toggle switch to “Off” and check the electrical circuits, check pump rotation, and check oil fill.
  • Operate the system for at least fifteen minutes, check that the pump speed, motor speed and the hydraulic pressures fall within parameters as indicated on the Hydraulic Schematic.


Only qualified hydraulic repair technicians, fully aware of the hazards should perform the above retrofit.

Note: Kenway does not intend for these instructions to be fully encompassing.

Charging an Air Conditioning System (New or Completely Empty)


1) The ambient must be above 60 degrees Fahrenheit to evacuate and charge an air conditioning system. The refrigerant tank may be placed in a pail of warm water to raise the tank pressure to facilitate charging. Tank pressure must be higher than system pressure to charge system. The typical tank pressure for charging is 40-100 psi.

2) The refrigerant service hoses must have shutoff valves within 12” of the end of the service hose to be attached to the A/C system to be serviced.


Refrigerant is under pressure. Use safety goggles to prevent eye injury and gloves to prevent frostbite. Do not wear loose clothing that may get caught in moving parts.

The following steps will describe how to charge an R-12 or R-134a air conditioning system that uses a receiver drier with a sight glass using the vapor only charging method.

Step 1: Remove the protective caps from the charging ports on the A/C system to be charged.

Step 2: Connect the blue low side service hose to the blue compound suction gauge on the manifold gauge set and to the suction service port on the largest line at or near the compressor on the A/C system.

Step 3: Connect the red high side service hose to the red discharge gauge on the manifold gauge set and to the discharge service port at or near the compressor on the high pressure line on the A/C system.

Step 4: Connect the yellow supply hose to the center connection on the manifold gauge set and to the suction port on the vacuum pump. Evacuate for a minimum of 45 minutes.

Step 5: Close the manifold gauge valves. Disconnect the yellow supply hose from the vacuum pump and connect it to the refrigerant tank.

Step 6: Purge any non-condensable (air) out of the yellow supply hose (refrigerant tank to manifold gauge set).

Step 7: Place the bulk refrigerant tank on a certified scale to either weigh in the specified amount or refrigerant or to record the amount of refrigerant the technician puts into the system for future reference.

Step 8: Open the blue low side valve a little at first to allow the refrigerant to enter the system slowly, then open the low side valve all the way. Do not open the high side valve. If you were to open it and forget to close it when the machine is started and the air conditioner is turned on, the high side pressure could cause the refrigerant tank to explode! Observe the gauges, the low side and the high side should equalize at the same pressure as the refrigerant tank.

Step 9: Check for leaks with a leak detector. If leaks are found, correct the problem and if necessary go back through the preceding steps before continuing on to step #10.

Step 10: Start the machine and turn the air conditioning on to its maximum setting – toggle switch set to air conditioning, fans on high, thermostat set to maximum cool and the doors and windows open.

Step 11: Monitor the scale as to amount of refrigerant charge that has been pulled into the system. When the specified amount for the system is reached, close the valve on the refrigerant tank then the valve on the gauge set.

Step 11a: If the charge amount is unknown see Method: Seat-of-Pants Vapor Charging.

Step 12: Allow the system to run for three-five minutes. Place a thermometer in the louver closest to the blower motor. Record louver temperature, ambient temperature, and pressures for future reference. Check the refrigerant sight glass on the receiver drier. The sight glass can be clear or milky but should not have a steady stream of large bubbles circulating through it. Large bubbles can indicate a contaminated refrigerant charge (air) or insufficient charge. Follow method as describe in “Seat-of-Pants Vapor Charging “ section to determine whether the refrigerant charge is low.

Terex Crane Typical Charge Amounts for Kenway units are as follows:
(Note: compressors supplied with Kenway systems have sufficient oil in them for the entire system)

RT and Upper systems: 2.0 lbs of 134a refrigerant

CD 100 and 200 series: approx. 3.0 lbs of 134a refrigerant

Trucks or lowers: approx. 2.75 lbs of 134a refrigerant

Method: Seat of the Pants Vapor Charging

The theory for this method is, when a TXV/receiver-drier system goes into overcharge, the RD is completely full of liquid refrigerant so any additional refrigerant added to the system will liquefy and back up into the condenser coil. This decreases the amount of condenser used for condensing. In order to remove the heat generated from the evaporator, the discharge pressure must increase and since the liquid refrigerant is in the condenser longer it is subcooled more. Under laboratory type conditions, factory charges are determined by measuring subcooling and other system parameters,

Many AC technicians have very good luck charging R-134a systems without measuring subcooling. They basically charge a system like an R-12 system but carefully monitor the discharge pressure.

Since in ambient temperatures higher then 80° F, the sight glass of the receiver drier may not become clear, the technician watches for the bubble size reduction.

If the sight glass clears, he will add an additional .5 to 1.0 lbs depending on size of the receiver drier. If the discharge gauge reading should jump and remains elevated, he will need remove some refrigerant to restore the discharge pressure reading.

If the sight glass doesn’t clear, he will gradually add refrigerant and monitor the discharge pressures, when the pressure creeps up 5-10 psi he will stop and sometimes recover some of the refrigerant.

Care must be taken that no other factors are affecting the discharge pressure. An example is the technician is charging in a garage which continuously warms up during the charging process. The discharge reading gauge reading will climb as a result of the ambient temperature change.


This method relies on monitoring charges in a measurable AC system parameter. The technician must use his knowledge and experience to make a judgment, which takes in the affects of environmental changes during the charging process to determine whether the system is properly charged.

Another resource for technicians to obtain information is the Mobile Air Conditioning Society.

Model 9027 CondenserOPTIONS:

  • Air Conditioning (R134a) and/or Hydraulic Oil Heat
  • 12 Volt or 24 Volt
  • Gallon configurations are 6-10, 11-15, 16-20, 21-25, 26-30, 31-35 GPM
  • Brackets for vertical mounting


  • Housing is made of 7 gauge through 3/8 thick steel with black powder coated finish
  • Shielding is made of 18 gauge stainless steel
  • Single mounting style with standard horizontal positioning of the whole unit
  • Uses belt drive system with bolt adjustment of belt tightening
  • Uses all around shielding from moving parts
  • Air Conditioning Unit includes compressor, condenser, drier, and binary switch
  • Hydraulic Unit includes pump, motor, relief valve, and heat developer block
  • Connections on unit: A/C = #6 (Drier) and #10 (Compressor) male O-ring, Hydraulic
  • Motor = #12 female Boss O-ring (2), Hydraulic Heat = #8 JIC male (2)
  • Air Flow = 1200 CFM
  • Weight = 140 LBS (A/C and Heat unit), 104 LBS (A/C only)

Wire diagram

IMPORTANT!!! Kenway is not responsible for the vehicle hydraulic system modifications. Use only a trained hydraulic technician. 

Wire schematic

OPTIONS:Model 321 blower

  • AC Only, Heat Only-Water or Oil, or Combo
  • 12 Volt or 24 Volt
  • Hose adapter ports for output of air for defrost or floor.
  • Fresh Air input.
  • Remote mounting of switches.


  • Housing is made of 16 gauge steel with black powder coated finish.
  • Filtered recirculated air.
  • Five adjustable flow and directional louvers.
  • Rotary controls for AC, Heat and 3-speed fan.
  • Block type expansion valve with easy hose installation.
  • Side cover. (not shown)
  • Connections: A/C = #6 and #10 Male O-ring, Heat = #8 male JIC (Oil), 5/8 ID Hose (Water)
  • Capacity: Heating = 30,000 BTU/H (Water)/ 20,000 BTU/H (Oil), Cooling = 21,000 BTU/H, Air Flow


Model 321 schematic

Beginning in January 2001, Kenway Engineering, Inc. made a change to our hydraulic drive motors. We are switching from the Commercial M315 to a Sauer Sunstrand SNM.

The SNM motor has many advantages over the M315. It has a built in outrigger bearing so it is not as sensitive to radial overload cause by belt over-tensioning (see 29-HYD-001 Belt Tensioning Instructions). It is has a wider RPM range, is more efficient, and has much less case drain.

Replacing the M315 motor with the SNM is straight forward. The mount bracket, pulley, and hardware are all the same. The installer must insure that the motor rotation is counter-clockwise(CCW) when viewed from the back. (Note: inlet and outlets are reversed)

There are a couple of differences in the installation of the SNM motor. The rear port and case drain fitting sizes have changed! The M315 has a –12 Boss O-ring port and the SNM has a –10 Boss O-ring port. The second difference is the case drain is on the rear plate unlike the M315 which is on the bottom of the motor. Re-route the case drain hose and secure with a nylon tie. Note: The case drain ports are the same size.




Update part to order