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Manitowoc SD0502A Ice Machine Troubleshooting?
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I saw this video about the fan cycle switch and it is a common problem on Manitowoc. I am confused as to how he bypassed the fan cycle switch in order to make sure the fan is good?
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your compressor is running in a overload condition. The question is why. Often the condenser gets loaded with grease in a kitchen. Not on the outside, but between the fins inside the coils. So is there a adequet amount of air moving thruogh coiul? The other possible is a tight bearing in the compressor, or wrong run capaciance for motor design and load. The latter is something you need a qualified tech to find and fix. It may even mean a new compressor if a winding or bearing inside the compressor is bad.
Normally a 500 pound machine will be 230 volt. Your looking at 20 amps to run a 115 machine. That means the wiring has to be 10 gauge, and good25 amp breaker breaker..
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It’s a PSC motor. If it starts during the boot/test section, it’s fine. Make sure what you are reading is for the single evaporator, air cooled 5oo lb machine. The service manual covers all machines That’s why we generally only refer techs to it. I wanted you to be able to understand the control system and how it worked.
To troubleshoot a ice machine, one has to have a good DVOM, clamp on ammeter, and digital thermometer. And know how to use them. By ohming out the motor windings and checking the load curent and voltage we can determine what is happening inside the compressor. We know that your motor overload has been tripping. The question is why. You say the the condenser has air flow. So now we have to look at the compressor electrical. Does it have the correct voltage? Is the run current below full load amps (on the compressor label as FLA) Do the winding’s ohm out correctly? Is the start relay and capacitors to spec.
If you do not have this equipment, or the knowledge to us it, You will be farther ahead calling a ice machine tech for this. Unfortunately, It sounds to me as you have a compressor problem that will need a tech to solve.
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I will clean the unit between the fins inside the condenser coils I did a start in service mode all control board lights energized and then it started up normal and then the compressor overloaded.
I ordered a Manitowok motor run capacitor, maybe the Jard brand doesn`t function properly on this machine? -
I bypassed the fan cycle switch with jumper wires and the condenser fan now stays on. The compressor does not overload but there isn`t any ice formation. The water is cold running over the ice plate. What could it be? No suction to form Ice?
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Alright buddy.
Listen e’re.
The reason your compressor is going off is either A, High head pressure or B, High temperature, C High amperage
High head can be caused by high temperature and vice versa. Hermetic compressors rely on the cold gas to cool it down, in order for the cold gas to exist, heat has to be removed from it which occurs in the condenser. There’s an evaporator (where the ice get’s made) and a condenser (where the big fan is, the thing strapped to it is a run cap or a start capacitor if it’s single phase).
Now, there’s normally a switch which monitors head pressure and turns the fan on and off as it goes along it’s a common tool across the boards. SO If it’s bypassed and the fan stays on that might just mean that you have a leak, honestly it sounds like there’s not enough refrigerant to go around.
A, your compressor is overheating, most likely due to insufficient cooling from the suction gas, due to an insufficient amount of suction gas which is due to a leak.
B, your fan switch is not cycling the fan motor, probably due to the head being low due to a leak. Otherwise, if there was a restriction or the TXV was starving the evap, your head would run high and the fan would remain on.
C, There’s no ice on the plate which if anything, there should be ice on the plate if there’s refrigerant in the system and the fan stays on, that head pressure should be fine.
D, if the TXV wasn’t working and was starving the evap, your head would run high IF there was a sufficient charge as all that refrigerant would be pumped against a wall but not going anywhere. If that was the case, the fan would remain on as your switch would detect the high head and cycle it on.
E, Low head and Low suction are normally a dead give away of a leak.
Now you don’t strike me as a refrigeration technician so I doubt you can check it, but that’s what it sounds like AND DO NOT try to charge it if you don’t have a gauges and aren’t EPA, these units are critically charged, 1 oz too much or too little can make it or break it.
Now let’s say it’s not what I said above,
It could be the start relay not cutting the start cap out causing your compressor to run while overamping, effectively overheating it as well, a simple amp meter would tell you if that’s the case. I’ve never seen a compressor run for 8 minutes with the start capacitor still engaged though, the overload will catch it long before.
So most likely, it’s A, B, C, D or E
So do me a favor and feel the larger of the copper tubes coming back to the compressor, is it warm or cold?
This unit probably has a hot gas defrost/harvest mechanism, that’ll be a solenoid valve on a non-insulated copper line. If it’s insulated it’s the suction/cold line. If it’s not insulated it’s the liquid/hot line. Feel both sides of the line with the solenoid valve, are they both the same temperature during cooling?, if so, the valve may be stuck open.
Let us know.
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“feel the larger of the copper tubes coming back to the compressor, is it warm or cold?” It is not cold but its not hot
The small un-insulated copper line on the bottom of the compressor that runs to the condenser is really hot near the compressor. When the copper line reaches the condenser it is not cold but not hot as near the compressor. Hope this helps Thanks!
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Let’s start from the beginning here.
Machine history’ Was it running before the cap was replaced?
Room temp, Air borne grease?
Water temp incoming?
Serial number? They used 3 different 115 volt compressors and the motor start components are not interchangeable.
Now we need to know what conditions the machine displays.
Motor run amps.
operating voltage.
Any water going down drain when running?
refigeration conditions;
compressor discharge should be very hot. To hot to hold on to.
top line to evaporator should be hot
fan should be moving a large amount of air tat feels warm.
bottom line of condenser should be just above room temp.
TXV outlet (larger line) should be very cold.
evaporator feed line at tne hot gas tee should be cold
Evaporator inlet should be very cold.
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olivero wrote:
Now, there’s normally a switch which monitors head pressure and turns the fan on and off as it goes along it’s a common tool across the boards. SO If it’s bypassed and the fan stays on that might just mean that you have a leak, honestly it sounds like there’s not enough refrigerant to go around.
Low gas will not cause the compressor to overload. That requires a high head or compressor internal problem or start / run componet problem. High head can also be a overcharge as well as airflow.
olivero wrote:
D, if the TXV wasn’t working and was starving the evap, your head would run high IF there was a sufficient charge as all that refrigerant would be pumped against a wall but not going anywhere. If that was the case, the fan would remain on as your switch would detect the high head and cycle it on.
A starving metering system (TXV) will cause a low load condition. That’s why we need the amps of the compressor. Overload is usually a full open valve. Whether the TXV or the hot gas leaking and raising the low side pressure. The hot gas will also cause the fan to cycle as well as not cool but heat the evaporator.
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Okay, sounds like it’s a refrigerant issue.
You’ll need a service tech for it.
If the compressor is running, the condenser fan is running, then that larger insulated line should be cold coming back. It sounds like it’s low to me.
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