Frequently Asked Questions
Welcome to our Frequently Asked Questions (FAQ) section, a comprehensive resource developed over years of real-world experience by our skilled technicians. This collection of common questions and expert answers has been carefully compiled to help you quickly resolve issues and better understand our products. We recommend browsing through these FAQs first, as many times they offer simple, effective solutions that can save time and get your equipment back up and running without delay.
Why does my dryer have unexplained shutdowns?
Investigate the following: Grain flow timer, Linear Limits, VFD (fault code on screen), soft starter (fault code on screen), and CAL temperature controller for low or high alarms.
When running in TruDry, my metering speed has a wide range, even though incoming grain only varies a few points?
Verify the level auger delay timer is not set over 60 seconds. If it is not, try decreasing by 15 seconds.
On the HMI, select “Settings” on the tool bar. Then select “Operational Setpoints”. Raise the “Min Discharge Speed” and lower the “Max Discharge Speed”. Make small changes, maybe 5% at a time, and observe if the range in speed of the metering narrows up.
My dryer stopped and I have a Discharge level warning on the HMI, yet I know my discharge is OK?
If the safeties of the auxiliary equipment are connected to C5 & C6, check out the auxiliary equipment.
Possible defective whisker switch (Profiles), mercury switch (Older profiles), or rotary bin switch (Towers).
My soft starters shows I am drawing more amps than I should?
Check for proper line voltages on all three legs.
Check for proper belt tension.
Investigate for worn bearings on both fan and motor.
Try opening or closing louvers on the air doors.
My MC Trax is not connecting?
Are you using correct user name and/or password?
Is your subscription current?
View MC’s video, “M-C Trax Installation and Setup”.
The Pinnacle LITE touch screen occasionally shows yellow warning triangles over the entire screen and the screen seems to freeze, but the control of the dryer does not seem to be affected. How can I get rid of these?
In remote cabinet, turn the 24vdc circuit breaker off and then back on.
Check cable connections.
Check indicator lights on the CPU and the Ethernet switch to verify good communications.
The HMI does not seem to be communicating with the CAL temperature controller?
First go to the CAL temperature controller and verify that it works. Is the top number (green) that shows the plenum temperature accurate? Can you change the set point, the bottom number? When you change the set point, does the gas valve actuator respond appropriately?
If the above are true, you can still operate the burner by monitoring and controlling with the CAL if you cannot control and monitor from the HMI.
Have your dealer’s service rep check for the proper address in the CAL parameters.
Replace the CAL with one that has been loaded with the proper parameters and communication address.
Plenum temperatures vary 5 degrees or more above or below the desired plenum set point?
Observe the percentage of valve opening by observing the actuator or observing the valve opening percentage on the HMI. With the plenum temperature at set point and the actuator is constantly at or near minimum opening, the indication is that the gas pressure is too high.
Adjust the gas pressure until the percentage of valve opening is in the 30% to 60% open range. This amount of opening provides a reserve of additional opening if additional heat is needed or the ability to reduce valve opening if less heat is needed, without having to adjust the gas pressure.
My FP-21 moisture sensor does not seem to be accurate?
Remove cover and check for moisture. Dry with a hair dryer.
Check that electrical connections are solid.
Check that full 12vdc is delivered to the sensor. Check between terminals 1 and 2 in the sensor.
Why does the LP gas line frost up and what can be done to resolve it?
Have the LP supplier add anhydrous methanol at each refill.
If the LP storage tank is a large commercial size, throttle back the withdrawal rate, either by adding a liquid regulator or reducing the discharge valve opening on the tank.
The dryer control circuit stays on when the switch is turned off?
Replace the shutdown delay timer relay.
The VFD does not run, even in local control. I have the proper voltage to the VFD and the keypad is illuminated?
Check the 24vdc circuit breaker in the high voltage cabinet. Use a voltmeter to verify 24vdc is present.
The 24vdc circuit breaker in the high voltage cabinet trips?
Check the mid grain RTDs and transmitters for shorts. -Check the moisture sensors for shorts.
On the CAL temperature controller and on the HMI screen, the plenum temperature is a negative number when it is obviously not that cold?
Check connections of the signal wires to the RTD or Thermocouple, at the terminal blocks, and at the CAL.
Possible bad RTD or thermocouple.
The plenum temperature as shown on the HMI and on the CAL controller does not seem accurate?
Use a temperature testing device and place its probe in the same place as the dryer’s RTD or thermocouple and observe the difference.
When the dryer is empty, the temperature shown on the CAL or HMI should be within a few degrees of actual ambient. Be aware that the sun shining on the dryer can cause some difference.
If the difference is more than a few degrees, replace the RTD or thermocouple.
My older dryer sometimes shuts down for no apparent reason. I can start back up again without resetting anything?
Check adjustment and operation of discharge overload door switch. Grain can back up in the take away, lifting the door, opening the switch, and killing the dryer. By the time you investigate, the grain has settled and allowed this door to close. If the dryer discharge is connected to an air system, look for back pressure to hold up or bounce the overload door, triggering a shutdown.
If the dryer is equipped with an Omron brand grain flow timer, replace it with kit PN 1289040.
If it is an older dryer, the mercury switch on the overload door might need replacing.
My dryer needs to be refilled but my fill switch or fill light does not illuminate and my fill equipment does not run?
Turn the fill switch to manual. If the system operates on manual but does not operate on automatic, investigate the level/fill timer.
Check for 120 volts at terminal #45 in the high voltage cabinet. If not found, investigate the rotary fill switch.
On my tower dryer, I sometimes get a dryer shutdown and a high or low temperature alarm is present on the HMI screen and on the temperature controller. I can clear the alarm and verify the plenum temperature is normal and then immediately restart the dryer?
Check connections to the RTD.
Faulty RTD. It is very rare, but an RTD can spike for a fraction of a second, causing an alarm condition on the temperature controller, even though plenum temperature is normal, which will cause a dryer shutdown.
I cannot clear the fault code on my Altivar VFD?
Clear the fault codes by turning off power to the VFD and then back on.
My mid-grain reading is -75?
Verify that the 24vdc circuit breaker in the high voltage cabinet is on.
Check that there is 24vdc to the RTD transmitters. On current models, this transmitter is in the well on the individual RTD. On older dryers, all four transmitters were in a box on the side of the dryer.
When I turn off the burner switch, the flame does not go out?
If fueled by LP, check for a hole in the vaporizer or a leak in any of the pipe connections.
Check for dirt in the solenoid valves, holding them open.
My fuel usage is way more than it should be. I have no trouble obtaining plenum temperature?
Verify that the dryer is full of grain at all times.
Verify all hatches are closed.
Check for leaks in the plumbing, especially inside the dryer.
The Belimo brand of actuator is not responding to what is shown for percentage open on the plenums page on the HMI?
At the terminals on the Belimo, check for 24vdc between the red and black wires. Check for 0 to 10 vdc between the white and black wires. This voltage should correspond to the percentage of valve opening as shown on the plenums screen on the HMI.
The actuator assembly might be bound up. Crack loose the single mounting screw found on the bottom of the box to allow the box and actuator to have a little movement.
I had the software for the HMI updated but some features are not functioning properly?
When updating software, update both the PLC and HMI at the same time.
I will fill my dryer with an elevator leg. How should I control it?
Leave the leg run continuously. Switch the equipment that feeds the leg on and off as the dryer calls for grain. Use terminals C1 & C2, found in the high voltage cabinet, as dry contacts for this command.
How can I estimate the discharge rate of my dryer?
With profile dryers, determine the RPM of the metering rolls by observing the metering rolls stub shafts at the end of the dryer. Multiply this number by the appropriate factor: 8’ 74 bu x RPM = Bu/hr, 12’ 111 bu x RPM = Bu/hr, 16’ 146 bu x RPM = Bu/hr, 20’ 182 bu x RPM = Bu/hr, 24’ 220 bu x RPM = Bu/hr.
My metering or sweep will run for a few seconds and then the dryer shuts down and the HMI screen displays a “Discharge Jam/Proximity Switch” warning?
Verify that the metering rolls or sweep are not physically jammed or locked up. -Verify the motor runs.
Verify that the proximity switch is as close to the target surfaces as possible without touching.
Check the cable connection at the proximity switch for tightness or moisture.
Pass a piece of metal in front of the face of the proximity switch. If the switch is good, you will see a small light illuminate on the switch. Verify by observing on the Digital Inputs screen if “I0.6-Disch Prox” is green. If one or neither happens, replace the proximity switch.
How can I check for water in my gas plumbing?
Tower dryers are equipped with drip legs. A drip leg is a vertical pipe, at the lowest level of the plumbing, that terminates with a ball valve and a pipe cap. Remove the cap and open the valve to allow any accumulated water to drain out. Close the valve and replace the cap using approved plumber's tape or paste on the threads.
I have a tower dryer with a self-cleaning floor. Do I need to do anything?
It is recommended you inspect both the interior and exterior daily and clean if necessary, per the caution decals on the dryer.
My CAL temperature controller reads 17 when the actual temperature is 60?
Check If the CAL is programmed for Celsius instead of Fahrenheit.
Can I use a VFD to drive my takeaway equipment and be controlled by the dryer?
Yes, use terminals C3 & C4, which are dry contacts found in the high voltage cabinet, as the command signal for the VFD you are adding. The speed signal for your VFD will be obtained from the dryer’s VFD. Consult your MC dealer for proper connections.
Can I still operate the dryer if the motor on my sampler stops?
Yes, in manual or TruDry. You will need to manually sample and test the moisture of the discharged grain with an external moisture tester.
Why does the moisture sensor not read proper grain moisture content?
Check the following when the moisture sensor isn’t (should be doesn’t) read the proper grain moisture content.
Wiring cable from moisture sensor to PLC unit may not have the shield grounded properly. Shield should be grounded at the high voltage cabinet but NOT at the sensor.
I cannot get enough heat on my Tower dryer?
Is the gas source adequate? Are the supply lines large enough?
Check for water in the lines by checking at the drip legs.
Check that all valves are functioning properly.
Check strainer.
Check for adequate pressure provided by the regulator(s).
Burner holes need cleaning. A visual inspection is not adequate. You must physically probe each hole. A Maxon burner uses two different hole sizes. They are drill size #47 (5/64”) and #50. A midco burner has 1/8” gas holes and #42 air holes.
My tower discharges at a higher rate than it should for that speed. I cannot slow it down enough?
Sometimes, the grain characteristics might cause a faster discharge rate than normal.
If equipped with 4 sweep arms, remove two.
If equipped with two agitator fingers, remove one.
Move the sweep fingers at the end of the sweep arms, back one hole each.
My Pinnacle screen looks normal but I cannot start anything on the dryer?
Press the “Alarm Reset” button on the screen. Alarms must be cleared before the MCR (Main Control Relay) will latch.
How long should the sampler auger run after I turn off the discharge?
The amount of time the sampler auger runs is controlled by the Mini Auger Timer, found in the high voltage cabinet. Set this timer to the maximum setting.
My moisture control board (Moisture Matic) blows its one amp fuse?
Systematically disconnect wires connected to the board to isolate the source of the short, except for the 120 volt source and neutral. Begin by disconnecting the leads connected to the Hot and Cool terminals. If the indicator lights are shorting out, it will cause the fuse that protects the board to blow. If all wires are disconnected and the fuse still blows, replace the board.
I suspect I have trouble with signal cable connections (Yellow, gray, or black cables used on exterior of dryer), causing interruptions of signals?
Spray electrical contact cleaner on both the male and female parts of the connection to make sure both contacts are clean and free of moisture.
Make sure connections are tightened snugly.
How can I make the TruDry respond to incoming moisture changes more accurately?
On the HMI, select “Settings” on the toolbar. Then select “Operational Setpoints”. Raise the “Min Discharge Speed” and lower the “Max Discharge Speed” a little. Make these changes in small increments to determine what will work best for you.
On the HMI, moisture reads “0”?
Go to the “PLC I/O” on the HMI tool bar. Arrow to the right until you find the screen labeled “Moisture/Temperature Analog Inputs”. Observe the values under “15 sec”. Warm up the temperature probe and the value on the screen should change. Touch the sensor blade and the sensor box at the same time. After 15 seconds, that value should climb into the 20s or 30s. If one reading changes but not the other, chances are the sensor needs replacing. If neither temperature nor moisture responds, check wiring connections, and 24 vdc delivered to the sensor before replacing the sensor.
Consult with your MC dealer’s service department before replacing the sensor.
I cannot get my control/safety circuit to lock in?
Pinnacle Lite:
Observe any red warning screen that might be present. If present, this screen will indicate the problem.
Check the alarms history to find the last alarm that has occurred. Touch “Alarms” on the tool bar to access this screen.
Go to the “PLC I/O” page. The top item on the left side of the screen that is dark is the cause of the problem. Investigate and correct that item.
Are all of the high limit lights on and is there 120 vac at terminal 23? If so, the safety circuit is OK, which means you must investigate:
Grain Flow Timer has timed out or the Grain Flow Timer is defective.
The main relay or the relay-timer board is defective.
Is there a CAL temperature controller alarm present?
CAL temperature controller is possibly defective.
Pinnacle 20|20:
Observe any yellow or red warning screens that might be present. If present, they could provide the reason for the problem.
Check the alarms history to find the last alarm that has occurred. On the home screen, touch “Historical Data” and then “Alarm History”.
On the home screen, select “Troubleshooting” and then “Safety Circuit” of from the “Controls” screen select “Safety Circuit”. An item that is tripped will be dark. Investigate and correct that item.
I have a NG export or Canadian model dryer. When the burner attempts to ignite, the safety circuit dies?
-When the burner attempts to ignite and the gas solenoids open, the gas pressure drops, triggering the Low Gas Pressure safety switch to open, interrupting the safety circuit. Slightly increase the gas pressure by adjusting the regulator.
The burner will not ignite?
Verify that the AC circuit breaker is on. (Pinnacle 20|20 dryers)
Verify that the gas supply is present and adequate.
Verify the pipe train is not plugged with water by draining the drip legs, if equipped.
Verify the gas orifice holes in the burner are clear, by pushing the appropriate size drill bit through all the orifice holes. For Maxon brand burners use #47 (5/16”) and #50 . For Midco brand burners use 1/8” drill bit.
On older Tower dryers that use a Maxon brand of burner, remove an end cap off one end of an orifice pipe and verify the pipe is not filling with debris.
Inspect sparkplug for cracked ceramic and proper gap. Inspect soundness of high voltage wire.
10 to 15 seconds after the ignition is turned on, you should hear the solenoid valves click (or see the proof of closure valve start to move). If not, first investigate the valve relay is it activates after the purge. If not, the ignition board is possibly faulty.
If gas is present and the valves click, the ignition board (or ignition transformer in 12’ or 18’ Towers) is probably not providing the needed spark.
The NG eddy on older natural gas fueled venturi burners might be missing.
Too much or too little gas pressure as regulated by the pressure regulator(s) and the modulating valve.
Burner ignites but stops after about 7 – 10 seconds?
Inspect flame sense probe and wire. Verify flame sense probe is not grounded out against the burner, the ceramic is not cracked or the wire grounding out against any metal.
Possible faulty ignition board.
Cannot obtain or maintain desired plenum temperature?
Verify the plenum temperature readout is accurate.
Verify that all hatches and doors are closed and latched.
Verify that the dryer stays full of grain and does not lose the air seal that the grain provides. For example: On a Profile, the hopper grain level should never drop into the hopper sight glass window.
Verify the burner orifice holes are all open and that with older Maxon burners debris is not accumulating in the burner orifice pipes.
Verify there is no water in the pipe train.
Verify the blowers have correct rotation.
Verify blower belts are of proper tension.
Verify adequate gas supply and pressure.
With conditions constant, drying rate decreases?
Verify plenum temperature is maintained.
Verify blower belt tension.
Inspect for dirty screens.
Cannot obtain the desired drying rate?
Does the operator have unrealistic expectations?
Is grain being over dried?
Are recommended plenum temperatures being used?
Occasionally, weather conditions, crop condition, or grain characteristics make drying more difficult.
Upon starting a burner, the plenum temperature overshoots the desired set point and/or either trips the high limit thermostat or causes a high temperature alarm?
Possible too high gas pressure.
High limit thermostat not set correctly. Rule of thumb: Set 30 to 50 degrees above desired plenum temperature.
If equipped with high-low fire, start the burner in low fire. Leave in low fire until the rise of plenum temperature slows down. Only then switch to high fire.
How shall I clean the exterior screens?
If the dirt is light, a brush/broom might be sufficient.
If the perforations are plugged, brushing will not be sufficient. Use compressed air or use a pressure washer. You do not need to remove the grain from the dryer. Leave the grain in the dryer while you power wash, as very little moisture will enter into the grain column.
Metering rolls or sweep will not run?
Metering rolls:
Loosen the idler sprocket to remove roller chain. Start the metering to verify metering motor and gearbox run. Under normal conditions, you should be able to turn the metering rolls by hand by grasping the sprocket with your hands. If not, use a pipe wrench on the shaft and it should turn with little effort. If not, something is broken or a foreign object is jammed in the metering rolls, which will require removing grain from the columns to access the metering rolls.
If the dryer has sat idle full of grain for a period of time, especially in wet or freezing weather, the grain has either packed or froze around the metering rolls. To thaw out or partially dry the grain around the metering rolls, remove one or two auger covers in the bottom plenum and block off the discharge to prevent escape of heated air. Run the bottom burner. Heated air will find its way through the discharge auger area to the metering rolls to thaw or dry them out.
Tower sweep:
Upon initial filling or if the dryer has been idle for a time while filled with grain, will pack grain around the agitator finger(s) of the sweep arms, preventing the sweep from turning. -Gain access to the sweep area. Use some type of bar to work in and agitate the grain in the discharge area of the column for a couple of feet in front of the agitator finger. Try running the sweep. Repeat as needed.
To prevent this from happening, while filling, run the sweep at minimum speed. The grain in the bottom portion of the dryer will have to be recycled anyway. If the dryer will be idle for some time, periodically run the discharge for a few minutes.
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