Midmark M9/M11 “New Style” Error Code C987 Leave a comment
In this article, we’re going to explain one of the many error codes that can affect your Midmark M9/Midmark M11 autoclave. This article will focus specifically on error code C987. We’ll tell you about the problem, what displays when the error occurs, its possible causes, and the course of action to take to resolve said error.
However, if you’re more of a visual learner, we have a video on this error code available here.
And if you just want to talk to someone, call our Free Tech Support at 704-966-1650 Option 3.
Display/Symptom
C983: STERILIZE MODE HI-LIMIT OPEN
UNPLUG / REPLUG UNIT
High-Limit Thermostat Opened for At Least 0.25 Seconds During STERILIZE Mode.
Causes, Checks and Actions
Possible Cause 1: High Limit Thermostats Open
- Check: Verify if unit is still overheated.
- Action: Unplug unit for 60 seconds, then plug unit into a dedicated, properly rated circuit. Allow unit to cool for 30 minutes.
Possible Cause 2: Temperature Sensor Malfuncitoning
- Check: Check for residue build up on temperature sensor probe.
- Action: Clean sensor probe with Speed-Clean, distilled water, and abrasive pad.
- Check: Check that nothing is touching or crowding the temperature sensor. (Example: trays, pouches, cassettes, etc.)
- Action: Reposition items so nothing touches or crowds the temperature sensor.
- Check: Perform Temperature Sensor Resistance Test. Allow sensor to cool to room temperature before testing. Acceptable range 1.07-1.1K Ω. Refer to: Temperature Sensor Resistance Test
- Action: Replace Temperature Sensor
M9 Temp Sensor OEM available here
M11 Temp Sensor OEM available here
- Check: Perform Temperature Sensor Supply Voltage Test. Disconnect sensor harness from J12 on PC board. On pins 1 & 2 acceptable range is 4.0 – 6.0 VDC. Refer to: Temperature Sensor Supply Voltage Test
- Action: Replace Main PC Board
M9 PC Board OEM available here
M11 PC Board OEM available here
Possible Cause 3: High Limit Thermostat Malfunctioning
- Check: If error code does not reset… Perform: Thermostat Continuity Test Meter Reading – Anything but OL
- Action: Replace Thermostats
M9 Thermostat OEM available here
M11 Thermostat OEM available here
Possible Cause 4: Loose/Damaged Wiring Connections
- Check: Check wire connections at high-limit thermostat and at J5 on Main PC Board.
- Action: Secure / Repair loose or damaged wire connections.
Possible Cause 5: Door Spring Missing/Damaged
- Check A: If the door motor releases the latch, but the door remains closed, Inspect door spring for damage.
- Check B: Verify if door is at the vented position. (Push in on door with out lifting handle)
- Check C: Verify the QTY of door springs. (M11- QTY 2, M9-QTY 1)
- Action: Replace Door Springs
Midmark Door Spring OEM available here
- Check: Verify door springs are at a 45 degree angle.
- Action: Place door spring at a 45 degree angle.
Possible Cause 6: Door hinge Binding
- Check: Check for binding or build up of debris in the door hinges.
- Action: Clean debris from hinges.
Possible Cause 7: Facility Voltage too High/Low
- Check: Test facility supply voltage. Voltage must be… 115V models: 104 – 127 VAC 50/60 Hz 230V models: 207 – 253 VAC 50/60 Hz
- Action: Contact an electrician to modify voltage.
Possible Cause 8: Heating Element Malfunctioning
- Check: Inspect heating element. Heating element should lay flat in the bottom of the chamber. Heating element should be free of any flaking / pitting. Perform: Heating Element Resistance Test (should read 9-11 Ω)
- Action: Replace Heating Element
M9 Heating Element OEM available here
M11 Heating Element OEM available here
Possible Cause 9: PC Board Malfunctioning
- Check: Perform: Heating Element Supply Voltage Test (With harness attached to leads should have line voltage in test mode)
- Check: Perform: Main PC Board Relay Test (Check TP1 & TP2 for an acceptable range: 10 to 14 VDC)
- Check: Perform: Main PC Board Pressure Transducer Voltage Test (Acceptable range: 4.0 to 6.0 VDC)
- Action: Replace Main PC Board
M9 PC Board OEM available here
M11 PC Board OEM available here
Possible Cause 10: Sterilizer overloaded.
- Check: Check the size of the load. (Refer to User Guide)
- Action: Reduce load size.
Possible Cause 11: Sterilizer was unplugged, then plugged back in while thermostat was still tripped.
- Check: Verify if error was preceded with other error codes. (i.e. C983, C573)
- Action: Unplug unit for 60 seconds, then plug unit into a dedicated, properly rated circuit. Allow unit to cool for 30 minutes.
As always if you have any questions about this process or anything else please feel free to contact us and take advantage of our “FREE TECH SUPPORT.”
We also offer FREE VIRTUAL TECH SUPPORT to “See and Talk” with a “Real Time Live Technician” for any problems you may be in need of help with.
You can also use our “FREE MAINTENANCE PROGRAM”. Take the guesswork and worrying about what unit is due for maintenance and which maintenance cycle it is time for. We will keep track of all your autoclaves and let you know when it’s time for anything.