10 Questions You Should to Know about box truck refrigeration unit

Common Problems And Solutions Of Transport Refrigerator Unit Jun 28, Views: KingClima  is professional and leading transport refrigeration units manufacturer and supplier in China and we devoted to the customers demands to help customers built one-stop van refrigeration and box truck reefer unit business. Here we concluded into some common problems from customers that our sales team and technology teams meet and we are also matched with solutions to it.



On the definition of evaporation temperature, condensation temperature, re cooling temperature and intermediate temperature:
 

1. what is the evaporation temperature of the transport refrigeration unit ?

A: the temperature when the refrigerant in the evaporator boils and vaporizes under a certain pressure is called the evaporation temperature.
 

2. What is condensation temperature of transport refrigeration unit?

A: the temperature at which the gas refrigerant in the condenser condenses into liquid under a certain pressure is called the condensation temperature.
 

3. What is the re cooling (or subcooling) temperature of the van refrigeration or truck refrigeration?

A: the liquid refrigerant after condensation is cooled to a temperature lower than the condensation temperature under high temperature and high pressure, which is called the recooling temperature (or supercooling temperature).
 

4. What is the intermediate temperature?

 A: the saturation temperature of refrigerant in intercooler under intermediate pressure (P2) is called intermediate temperature.


Photo: KingClima  Van Refrigeration Units Installation Photo

About the definition of the suction temperature and discharge temperature of the compressor:
 

1. what is the suction temperature of the box truck reefer unit compressor?

 A: the suction temperature of the compressor can be measured from the thermometer in front of the suction valve of the compressor, Generally, the suction temperature is higher than the evaporation temperature, and the difference depends on the length of the return pipe, the insulation condition of the pipe and the outlet temperature of the evaporator. Generally, it should be 5 ~ 10 ℃ higher than the evaporation temperature (called superheat).
 

2. What is the discharge temperature of the compressor?

A: the discharge temperature of the compressor can be measured by the thermometer on the discharge pipeline. The exhaust temperature is directly proportional to the pressure ratio (PK / P0) and the suction temperature. If the superheat of suction is higher and the pressure ratio is higher, the exhaust temperature will be higher. Otherwise, on the contrary, the exhaust pressure is slightly higher than the condensation pressure.
 

3. What is the reason for the high exhaust pressure?

1. There are many mixed gases in the high-pressure part of the system and the unit. Elimination method: stop the compressor operation, start the cooling water pump for circulation, open the vent valve to 1 / 5 ~ 1 / 6 circle, check the pressure gauge reading at any time (ensure the accuracy of the pressure gauge, refer to the corresponding pressure and temperature of the thermal property table), and the vent time depends on the pressure close to the value after discharge.

2. Condenser heat exchange tube scaling and debris removal method: remove the condenser cover on both sides. A. Rinse with high pressure water gun. B. Please deal with it by professional cleaning company. C. Use cloth strips to wipe back and forth.

3. The condenser accumulates too much liquid and oil. The elimination method is: A. fill too much refrigerant and discharge or discharge into another container. B. Check whether the outlet valve and balance valve are all opened (check if the valve head falls off if necessary). C. Drain the excess oil.

4. Condenser inlet and outlet pipe lead pad damage caused by cooling water short-circuit cycle elimination method: remove the cover, remove the lead part rust, replace the rubber pad.

5. The inlet temperature of cooling water exceeds the design requirements. Elimination method: clean up the dirt of cooling water tower, especially the water distributor and packing are evenly distributed and whether the inlet is blocked by foreign matters.

6. Elimination methods for insufficient cooling water flow: (the water temperature difference between the inlet and outlet of condenser exceeds the requirements) whether the mechanical wear in the water pump is too large or the foreign matter is blocked, whether the water valve, check valve and filter screen are abnormal, whether the head meets the requirements, and whether the pipeline direction and specification meet the requirements.


The suction temperature of the compressor is higher than the evaporation temperature (higher than the specified value):
Troubleshooting: (1) insufficient refrigerant in the system: Supplement refrigerant. (2) Insufficient refrigerant in evaporator: open the throttle valve. (3) If the water content exceeds the specification, check the water content. (4) Small opening of control valve, small liquid supply: increase the liquid supply. (5) The insulation layer of the low pressure pipeline of the refrigeration system is not good: check the insulation layer and replace the insulation material if necessary.

Compressor suction pressure is too low Troubleshooting: compressor suction pressure is too low: Troubleshooting: (1) liquid throttle valve or suction filter blockage: disassembly inspection and cleaning. (2) Insufficient refrigerant in the system: replenish refrigerant. (3) Insufficient refrigerant in evaporator: open the throttle valve. (4) There is too much oil in the system: find out the oil accumulated in the system and let it out.

To Conclusion

The above are generally showing some problems that customers install the box truck refrigeration unit or van refrigeration that will meet, both of them are about temperature and compressors.

It is not easy for the end-user customers to install such a big equipment in their trucks or vans. It will need more professional people help to install. KingClima  has no centers in overseas as for now, our factory and production lines are all in China. So we welcome distributors to join us as our partners to resell our transport refrigeration units in local areas to supply the after-sales service. We also give our distributors a strong business support in the business initial phase. So warmly welcome your join! Please send us your requirement to our :   Share:

I am not the man to ask this question to.

I am known for setting full continuous. I'll burn the 100 gallons under that reefer first and add more any time before I'll allow that temp to rise.

The only time I cycle is when hauling medicine. Set point 60 and there are times in winter it's actually keeping it heated at 60 when its -10 outside.

I have had reefer loads rejected before usually after picking up a load that has been allowed by the fuel boy to run dry at the yard. It spoils on the way to delivery across the USA. Those go into landfills. I think I only had three rejected so far and that's about all of them too. Two went into landfills and the one was resold at a loss to whole sale which became it's own delivery.

This does not include the occasional case or a pallet of this and that ranging from meat to butter and stuff because the forklift made a tiny cut in the box. Those go to OSD for insurance purposes and then specifically handled just so to prevent diversion or sales into the black market so to speak for cash.

Now if OSD gave permission you toss that food into the corner and take home. Or trade it as currency to a shipper to get loaded in 10 minutes. It's better than money to certain peoples working in fast paced shippers. They are hungry. I recall 50 pounds of butter in stick form vanishing in 5 minutes and I was loaded in 15. Just enough time to cross the GWB outbound before the crush loaded. Hunts Point got the rest.

The best shippers who I maintain loyalty to certain food items are those who toss something extra into the tractor for us on top of the loading. MM Mars come to mind. Mt Olives is another and so on. Pompeii is a third.

Most of the time we do not have the load on long enough to burn through the 100 gallons.

HOWEVER.

We were a husband and wife team with FFE one day in summer. We were told by not just Dispatch but also a broker plus one of our Company Vice Presidents to skip the Salinas truckstop and go right away into the Americold Facility emergency quick now load.

Well we got there already precold to -25 or so where they told us they aint ready. So we sit in front of their two docks on the corner burning all of our tractor fuel at high idle day and night and burning all of our reefer fuel maintaining precool for just about 3 days and two complete nights. Emergency my ###. They probably had visions of christmas joy in detention pay sitting on our gold plated butts.

A absolute waste of our time and we got paid ZIP. The first thing we had to do after loading was go buy 400+ gallons of fuel. Im pretty sure that made a dent on whatever profit there was to be made.

Keep on cycle when temp outside is not too cold or too hat. When it's too cold you have too protect it from freezing fuel may not start again when too hat battery may not like it too start that every 20 minutes. But when I got to sleep it on continues off cours depends on temp outside.. and ice cream continues for shure