Vendo HD56A Cooling Question

[JimG]

Hello! I just recently acquired a Vendo HD56A and it would not cycle.  I replaced the thermostat and now it cycles but the problem is I have it in the garage and the temp during the day is about 94-95 degrees F.  I have the thermostat not to far above the minimum setting before it would shut off completely at this setting it cools to about 32 degrees then shuts off and then turns back on about an hour and a half later when the temp rises to 45 or 46 degrees.  Should it be cycling more frequently? Also when the temp is at 94 or 95 in the garage in runs along time and seems to struggle to get to the 32 degree cutoff point, at night and in the mornings when the temp in the garage is in the 78-81 range it seems to be able to keep up a lot better.  Is my machine low on coolant? Or is the compressor on its last legs? Just trying to figure out what the proper cycling range should be.  Also I've read on other forums that the evaporator fan should run 24/7, but on my machine it only kicks on when the machine cycles and then turns back off when the compressor turns off.  Is this a problem? It looks as though the compressor may have been changed at some point and the wiring harness appears to be newer.   Thanks in advance for your replys!

[johnieG]

first try to clean the condenser coils ( the lower black radiator down by the compressor) unplug the machine, & brush off all of the dust-bunnies from the front & blow it out with compressed air if available, try not to over-spin the fan motor ( it's not a turbo charger but it will sound like one if you over speed it with the compressed air & you may damage its motor, temporarily stuff a rag in it to keep it from spinning, just don't forget to remove it before you plug the machine back in!) 

Be very careful if you decide to try to power-wash it or use the garden hose on the condenser fins, the old fan motors really don't like to get wet, it may trip your GFI or your circuit breaker if it does get wet, so put an over size baggy & tape it up before you hit it with any water, again with the machine unplugged of course!   

Oh & If the fan you are referring to is also next to the compressor, it's called the condenser fan & yes it will cycle on & off with the compressor, the evaporator fan is up top inside with the soda's & runs 24/7/365.

[MoonDawg]

Also I've read on other forums that the evaporator fan should run 24/7, but on my machine it only kicks on when the machine cycles and then turns back off when the compressor turns off.  Is this a problem? It looks as though the compressor may have been changed at some point and the wiring harness appears to be newer. 

      The evaporator fan should run all the time or you won't get constant cooling inside.

[JimG]

Ok. Is that difficult to fix? As my fan definitely stops when it cycles (both fans including the interior one).  I will try blowing out the coils, but they both seem clean.

[MrMark]

JimG,

You may be low on gas, but keep this in mind - there is no fixed "cycle rate". The "cycle rate" all depends on the heat gain of the box, and when the temperature difference between inside the box and the ambient outside air (the garage air) is less, the "cycle rate" is less. When it's more, the "cycle rate" is more.

Also, when the ambient is warmer, it is harder for the compressor/condenser to reject heat, which in turn causes longer run times.

If the deck is pretty much all original, I would suspect the hot gas line leading from the compressor to the condenser is leaky. For certain if there is a clamp on service port, it is leaking there, especially if you are still running R-12 (clamp-on's come in two flavors, those that leak, and those that are about to leak, regardless of what the manufacturers say.). Besides, the EPA say's to use a clamp on purely for evacuation of the system charge only. So when one is used, the system should be evacuated, the clamp-on removed, the hole sealed up, any system leak identified and repaired, the liquid line drier replaced or added (preferably to a Sporlan 032-S, 032-Cap, or 032-S-T), evacuate to <500 microns, then recharge.

As for the evap motor running all the time, look to see if the wiring has been modified in any way. If it has, then I would bet the fan is supposed to run all the time. If the wiring hasn't, then maybe the fan is supposed to cycle with the condenser, but I highly doubt it.

Just my two cents. javascript:void(0);

[MoonDawg]

Ok. Is that difficult to fix? As my fan definitely stops when it cycles (both fans including the interior one). 

       Follow the wires from the upper fan down to the compressor area, and tie them directly into the 2 terminals on the side of the compressor.