Reefer has difficulty to reach -10 temp

If the product was hard-frozen (0 or less), the trailer should be able to do better than that. Is the chute up and all the way to the back and not torn up front? The rear doors latched up at the top? Is it a corrugated floor or a flat floor? Is it a palletized load? (not all in sideways are they?) Is the intake area at the front clean and clear of any crap or plastic? Dirty corrugated floors not washed in forever and full of crud are not good for efficiency, either.

I'm sure an older trailer would make it hard, but if the unit is running optimally, it should at least be able to bring it down to -5 at night. I suspect it may have issues. I'd run a pre-trip on it at some point to see what it says.

 

Set at -22 it reached -7 last night now its98 outside its at 2 above

 

Yeah. I'd get it looked at to make sure it's cooling as well as it can. If it is, probably better to avoid frozen loads with that trailer in the hotter months. Between it's loss of R value and maybe small or defective cooling system, you're asking for trouble with frozen loads.

 

Reefers MAINTAIN TEMP of whatever product is loaded at.

ice cream, dough products are the most PIA for me.

When dispatched to get a load that either one of those, I precool reefer town to -20. (Thermoking on a Great Dane 53 foot which sometimes has a auxiliary reefer near the left rear of the reefer at the ceiling. (That one is at -20 as well, what a howler) 100 gallon cross wide tank near the landing gear.

I carry two manual thermoneters, -40 would be as low they go. Stick then both in a random pallet as forklift driver waits for me inside his inner curtians and it comes out to -23 and -26 it's good to go into the trailer. The next one is being measured while forklift number one is running to grab pallet number three. number two might show -19 and -22 rougly but good enough for me in they go. Times wasting.

Eventually I have 24 pallets of Icecream filled up. Doors are closed asap. And sealed Shipper load and count.

I would me remiss if I forgot to remind people that shippers install two or three recorders into the entire rig with the load; Those recorders are not mine to touch or fool with. They represent a final insurance against loss of temperature at -20 if it happened.

Dough on the other hand.

I do not like to haul them. You can have God set point that trailer he owns to -100000 but once it begins to gain caloric energey, in order words begin to warmup;;; aint stopping that from heating up.

 

Do you have your floor drain holes plugged? They can make a difference for cold loads in hot weather. You can plug them without opening the trailer, with chunks of foam or even balled up paper, though if you don't have actual plugs, you will want to be sure that the holes stay stopped up.

Also, be absolutely sure your rear doors are properly sealed at the top. I had issues once with a load that was set for stop/start but ran almost continuously despite being at correct temp when loaded. I noticed later that the shipper had failed to seal the top driver side rear door latch. I was pushing a lot of warm air into the trailer while driving. Fortunately the load was onions, or potatoes, or something that wasn't too sensitive to a bit of warmth. The reefer was able to keep it in proper temp range. But it worked hard to do it.

 

Is the trailer Freezer rated or chiller rated? if its chiller it will take alot longer keeping temps at that low level which is kinda unfair on the poor uneducated driver. One hot summers day out in the Oklahoma panhandle i couldn't leave the warehouse till my temps were down to - 10 also i waited and waited all the while hoping and hoping it would get colder it'd reach about - 4 then no lower another driver who'd called out a fridge mechanic told me this he said " try unhooking the trailer and moving forward giving the fridge motor some space" i thought why not at this stage i was willing to try anything sure enough with in 45 minutes i was on my way outa there

 

Another reason to pull of under trailer is hot rear ends. every time you stop for the rest they heat front of the trailer where is air return. If you are loaded with something temperature sensitive frsh produce freezing can occurs on the rear as reefer will go crazy.

 

Rear door seals and Allignment can be a big pain...my boss is in a p@ssing and sh@tting match right now with one of our shippers, they rebuilt their docks and the angle now effs up the door hinges to where they don't seal right. You can literally feel cold air shooting out the back as you stand behind them. That will stop a reefer from reaching -10 or screaming for 6 hours trying to get there, shut off for 6 minutes and do it all over again.

If I have a frozen load and a reefer that is old or may have problems, I run it continuous if it's hot weather. Frozen is frozen, and once you set it lower than that 33-36 sensitive fresh produce setpoint, most reefers will put out the same energy whether you have them on stop start or continuous. Plus if the thing shuts off, then you will know for sure something is wrong. I'd rather have it howl continuously than shake the bunk and howl every 10 minutes.

 

Something else I learned about Carrier units the other day.

If they detect an alternator or charging problem, even if it is not enough to flag immediate service, the unit, if it is in start/stop mode, will not allow itself to reach the temp required to turn off.

Instead, the unit will run continuously and hold temp a couple degrees above setpoint until either the battery is fully charged, or the alternator reaches a point where it triggers an alarm.

If the setpoint is critical, you can lower the actual setpoint to make the unit hold in a correct range.

I have seen this half a dozen times with Carrier units at Shaffer.

When I finally got a Carrier tech to tell me what was happening, I tried to reach someone at Shaffer who can speak to the people that set parameters in the computers.

Specifically, I really think it would be appropriate for the reefer unit to display an error code when it detects a fault. If the fault is sufficient for the unit to change its behavior, it is sufficient to notify the driver.

I will be trying again to reach someone after the weekend.

 

Mine goes down to -4 at night in texas but 3 above in daytime but its hot as hell down here. I just booked a load of chicken going to the dump that another company lost down here so im guessing summer in the South is hard on all reefers