Chill Factor

| August 01, 2005

The message center display shows what’s going on in your reefer unit’s
microprocessor.

If you’re paid to deliver a load of ice, you won’t see a dime if you arrive with water.

A reefer driver is responsible for his load, and it’s his job to look out for trouble with the reefer and head it off, if possible. Reefers work the same way as your cab air conditioner, but they provide more cooling per gallon of fuel. They are powered by their own engine. Look at one example: in the case of the Carrier Transicold Ultra XTC refrigeration unit, a Kubota direct-injection diesel provides 36 horsepower at 2,200 rpm and glow-plug-assisted starting. We used this unit as a guide to reefer care practices.

We consulted Senior Technician Pat Naylis of Carrier Transicold Pennsylvania East in looking over an Ultra XTC, this one owned by New Century Transportation of Westhampton, N.J. The Ultra XTC offers extended service intervals; the microprocessor controls will even help you keep tabs on developing problems. A pre-trip checkout, partly done by the microprocessor or “micro” that controls the unit, will help guarantee that the unit will run reliably until you deliver your load in perfect condition.

Performing a pre-trip
Naylis recommends performing a pre-trip on your reefer unit each morning before setting out. The unit’s microprocessor is designed to perform a number of checks in an automatic sequence to help you find and fix any problems before you lose a load.

  1. Turn the unit off, allow it to sit for three minutes or so, and check the engine oil level.

  2. Glance at the coolant overflow tank [in this unit's case it is located in the top corner of the unit on the driver's side]. Never open the radiator cap unless the engine has cooled thoroughly.
  3. Glance at the fuel filter. If there is water or dirt obvious in the bottom of the bowl, open the drain cock and drain enough fuel into a safe container to remove the accumulated dirt or moisture. If you need to drain a lot of fuel to clean up the bowl, you can reprime the system by pumping the priming pump next to the engine’s injection pump. Just open the red valve, unscrew the top of the priming pump, and pump the plunger up and down to operate.
  4. Check the belts to make sure they are not cracked or frayed. This should not be a major concern as long as you inspect and adjust them at maintenance intervals.
  5. Run a pre-trip check of the system’s component via the micro. To do this, first turn the Start/Run-Off switch on. Then press the Select key until the message center display indicates “PRESS THE = KEY TO START PRETRIP.” Once this message shows up, press the = key below the up and down arrows.
  6. You’ll now see TEST #1 in the message bar. Verify that the complete display is turned on, all the lights in the light bar come on, and that the buzzer buzzes.
  7. Once the pre-trip is completed, the unit will continue running at the previously set temperature and in the previously selected running mode. “PRETRIP PASS,” “PRETRIP FAIL AND COMPLETE” or “PRETRIP FAIL IN TEST” will be shown if the pre-trip cycle was aborted by an alarm before completion. Any problems that were found will be spelled out. If an alarm is shown that allows the unit to continue operation (the pre-trip was completed), get the problem repaired as soon as possible. If the unit fails any critical tests, it becomes inoperable until repaired to prevent damage to its internal components.

Routine Maintenance
The reefer unit’s engine holds 15 quarts of oil and uses a large filter. This allows oil changes at 2,000 hours, unless you use Mobil Delvac 1 5W-40 oil, in which case 3,000-hour maintenance intervals are the standard. When using Mobil Delvac 1 and the special bypass oil filter, the maintenance interval is 4,000 miles.

The first step when doing the 2,000 or 3,000-hour maintenance is to make sure the engine has been running long enough (at least 30 minutes) to get the oil hot. Then shut down the engine.

To change the oil:

  1. Place a 20-quart pan below the drain plug and remove the plug. While the oil drains, make sure the pan can also collect oil from the oil filter, and then unscrew the filter with a strap wrench and remove it.

  2. Wipe the filter base with a clean rag. To replace the filter, coat the rubber gasket with clean engine oil. Then install and tighten it the number of turns past the point where the gasket contacts the base that are specified on the side.
  3. Allow a few minutes for all the oil to drain, wipe the plug and seating surfaces on the oil pan, and then reinstall and tighten the plug.
  4. Refill the engine with oil and start the engine and run it until oil pressure is established before shutting down for the remainder of the work.

To service the fuel filtration system:
The fuel filter should be changed at 2,000 hours unless an ESI (extended service interval) filter is used. Then the interval is 3,000 hours. This filter can only be fitted to newer models – check the service manual for specifics.

  1. Place a pan under the filter. Loosen the drain plug, and use a strap wrench to loosen the filter slightly at the top. Drain the filter bowl and filter. A drain hose can be connected to the drain plug.

  2. Once the filter has drained, unscrew it from the mount at the top and remove the bowl from the bottom. Wipe the bowl out with a clean rag, coat the gaskets at top and bottom with clean engine oil, and screw the bowl onto the lower end of the new filter and tighten it. It’s easy to tell which end the bowl is screwed onto – the filter must end up so the printing is right-side up.
  3. Fill the filter and bowl to the top with clean diesel fuel.
  4. Install the filter onto the mount and tighten with a strap wrench as recommended on the side.
  5. Open the red bleed valve. Then unscrew the priming pump plunger and operate the pump by pulling the plunger up and down slowly. When you feel resistance, the system should be getting full. To ensure proper prime, start the engine and run it while pumping until it runs steadily. Then shut it down and close the bleed valve.
  6. Clean the inlet strainer in the fuel pump by first unscrewing the mounting bolt that attaches the inlet fuel line. Remove the upper copper ring seal, pull the banjo fitting off the bolt and then remove the bolt, keeping the lower copper ring on the bolt. Unscrew and remove the strainer. Replace the seals if the rubber centers are worn.
  7. Blow the strainer out with compressed air and clean it in solvent; then dry and replace in reverse order.

Servicing the air cleaner:
Next, take a look at the air restriction indicator, located below the inlet air hose. The indicator will show red if restriction has been excessive, even if the engine is off when you’re looking at it. If the air cleaner gets clogged, the engine will also smoke quite heavily, Naylis says. But it normally won’t clog between maintenance intervals unless running in a dusty environment. If the indicator shows excessive restriction, the air cleaner should be replaced at more frequent intervals.

  1. Remove the left side door for access. Pull down on the upper hinge pin to disengage it and then remove the door.

  2. Unfasten the clips and pull the cover off the air cleaner assembly. Then remove the air filter.
  3. Press the new filter into position so that its rubber seal is forced over a fitting until it seats. Then reinstall the cover with the water drain downward and “TOP” marking at the top, and fasten the clips.

Belt checks
Belt condition and tension are critical. Belts will slip if tension is inadequate or they are glazed, Naylis says. This will result in engine overheating and high “head pressure,” the pressure in the condenser. This can result in compressor failure.
Inspect the belts:

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