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1085AC Manual



MANUAL #29-01-006   REV A   EFFECTIVE 2-15-99

Hydraulic H/AC


  1. General mounting instructions: 
    1. Drill all applicable holes into the cab - see diagram.
    2. The evaporator/heater unit is mounted behind the seat with four 5/16-20nc bolts, locks, nuts and four - 1" long spacers. See the hole diagram for mounting hole placement.
    3. The rear windshield washer unit must be relocated to the control console side of the cab.
    4. 24V power to run the Kenway system is located behind the access panel. It is located near the lower rear part of the seat mount. Attach Kenway power wire to the terminal on the large (60-amp?) relay with the red wire connected to it.
    5. The two drain tubes (if a/c is installed) are attached to the fittings at the bottom of the a/c-heater unit and are routed out the rear of the cab.
  2. The Electric Condenser (if used):
    1. Mount the electric condenser is mounted on the counter-weight about five inches from the backup alarm and centered on the rectangular fill plate that is welded onto the counter-weight.
    2. Position the electric condenser on the counter-weight. Mark and drill through the counter-weight with a 5/16" drill bit. Tap the hole with a 3/8-16nc tap. Bolt the condenser in place.
  3. Receiver Drier (if required):
    1. Mount the drier using the 3/8-16nc X 3/4" bolts provided.
    2. If the binary switch is not mounted on the drier, mount it there now.
  4. The Fresh Air Filter (if required):
    1. Center the fresh air base over the fresh air holes and drill the six 13/64" holes into the rear of the cab.
    2. Use the six self-tapping screws to attach the base to the cab.
    3. Place the filter onto the base and latch the cover into place.
  5. The Kenway Hydraulic Drive:
    1. Remove the machine left side panel to access the toolbox area.
    2. Install the two base extensions (angles) onto the hydraulic drive - if not already installed.
    3. Carefully position the hydraulic drive between the toolbox and the counter-weight.
    4. Weld the base extensions to the floor of the machine and use a little touch-up paint to prevent oxidation (rusting) of the unpainted metal surfaces.
  6. Hose Routing and Wire Harness Routing:
    1. Connect the oil heat hoses (if oil heat is required) to the Kenway hydraulic pump inlet and to the heat developer block outlet.
    2. Connect the air conditioning hoses (if a/c is required) to the compressor - use a little refrigeration oil on the o-rings.
    3. Route the hoses and the wire harness through the center of the boom superstructure with the other hydraulic hoses to the rear of the cab - use cab diagram for hose routing into the cab.
    4. See the diagram for the Kenway hydraulic drive hookup into the machine’s hydraulic circuit. 

mounting instructions


mounting instructions



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. 

This is the Parking information.

  • Jan
  • Feb
  • Mar


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.

Note: The typical air conditioning system refrigerant charge is about 2 lbs. of R-134a refrigerant and 5.5 oz. of PAG oil (SP20). 



The purpose for attaching the case drain from the hydraulic drive motor to the inlet of the oil heat pump is to eliminate the need for periodic oil changes in the oil heat systems with the small Kenway expansion tank. Some customers were experiencing oil breakdown in their oil heat systems due to high temperatures created in a small amount of oil (1 – 2 quarts). Regular oil changes are necessary to insure the oil stays in good condition.


This design replaces the earlier system that required 1 – 2 quarts of Dexron transmission fluid. It allows the oil from the Kenway motor assembly case drain to enter the inlet of the oil heat pump. The additional oil will overflow the oil heat system and will exit the expansion tank. Mixing of the oils will occur and filtering of the oil will take place in the main hydraulic system reservoir.

The case drain line leaving the overflow tank should be routed to the main tank return line. Do not route with other case drain lines if possible. Back pressure on the case drain lines need to be kept to a minimum – under 25 psi under any operating condition to protect the front pump seal from being pushed out of its seat.


Filling the oil heat system with oil after all heater lines, case drain lines, and motor inlet and outlet lines have been connected is done by the motor case drain.

  1. Set the heater controls to the ‘off’ position.
  2. Place a pressure gauge in the line between the motor and the pump to check case drain back-pressure.
    Start the machine and check for leaks and that the hydraulic motor is turning clockwise - as viewed from the pulley end of the motor.
  3. Let the machine idle for a few minutes and check for flow through the case drain line.
  4. Once there is oil flowing through the case drain, set the heater temperature control to ‘off’ and set the master toggle switch to ‘heat’. Set the toggle switch on the hydraulic drive to ‘on’.
  5. Let the oil heat pump circulate for a few minutes to work the air out of the oil heat system.
  6. When satisfied that all the air is out of the system, set the heater temperature control to ‘maximum heat’.
    This will change the sound of the oil heat system and heating should begin almost immediately.
  7. If the pressure in the case drain line exceeds 25 psi or no oil is entering the system check the flow of oil from motor – it should be from .25 - 1 gpm. If there is too little or excessive case drain leakage, replace the motor. If there is proper case drain flow, check the case drain hose or the main tank return line and correct any problems. Retest the case drain pressure.
  8. Remove the pressure gauge (if installed) from the case drain line. Check for leaks one more time.
  9. No other servicing of the oil is required. The oil from the main reservoir is filtered. Normal maintenance of the oil is all that is required. 
  1. Place a 0-2000 psi pressure gauge on the high-pressure test port at the heat developer block. Start the machine and engage the Kenway oil heat system.
  2. Adjust the cab air temperature to maximum and set the engine idle speed to approximately 1000 rpm.
  3. Remove the cap nut from the oil heat relief valve (mounted on the heat developer block) and loosen the adjusting screw locknut.
  4. Rotate the adjusting screw clockwise with a 1/4" Allen wrench to increase the pressure. The relief valve is set at 1200 psi. Be careful when rotating the adjusting screw so that when the screw stops turning (about 3 turns) not to force it any further. The maximum relief valve pressure that can be set is 1500 psi.
  5. Hold the adjusting screw with the Allen wrench and tighten the locking nut. Tighten the cap nut onto the relief valve. 

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.

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

electric condenserOPTIONS:

  • 12 or 24 Volt.
  • Low Profile Motors (Standard) or High
  • Performance Motors (Optional).
  • Roof Overhang Mounting.
  • Shock Mounts. 


  • Housing is made of 18 gauge stainless steel.
  • Side mounting brackets as shown.
  • Connections: Use A/C = #8 FOR and #6 FOR Fittings.
  • Unit shown with standard mounting brackets.
  • Height of Standard motor = 7.8” ; Height of High Performance = 9.6” 


electric condenser specifications