Midmark M9 & M11 Error Code C981 (SELECT)
The Error Code "C981" means the High-Limit Thermostat is open. This is normally due to lack of water inside the chamber
Before proceeding: Allow unit to cool for 30 minutes. Unplug unit for 60 seconds, then plug unit into a dedicated, properly rated circuit
When is the error code appearing?
The first step in determining the problem and it's solution is to take note of when the Error Code C981 is appearing. Once you know when the error code is appearing, scroll down & locate the proper chart for solutions
If The Autoclave Skips The FILL Mode
If, after you select a cycle and push start, the autoclave does not display filling, but goes directly into the heat up mode, then this is what you need to look for
| Display/Symptom |
Cause |
What to Check |
Solution |
C981 (Select): POWER UP MODE
HI-LIMIT OPEN
UNPLUG / REPLUG UNITHigh-limit thermostat opened for at least 0.25 seconds during POWER UP mode |
The Base Tray Plate or the Tracy Rack is not installed properly |
Inspect Base Tray Plate and Tray Rack for proper installation. (Angled end of Base Tray Plate must be toward the back of the chamber) |
Install Base Tray Plate and Tray Rack properly. Unplug the autoclave for 60 seconds before plugging back in |
|
Water Level Sensor Not Functioning Properly |
Check the Water Level Sensor Disc to see if it is damp or wet |
Dry Water Level Sensor Disc with a Lint Free Cloth and try another cycle |
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While there is an electical test you an perform to verify the water level sensor is malfunctioning, there is a more simple & direct way to test it |
Remove the Base Tray Plate & Tray Rack from the autoclave. Pour Distilled Water into the chamber until it touches the water level sensor & start another cycle. If it successfully completes the cycle, then you know the Water Level Sensor is bad & needs to be replaced
|
If The Autoclave Completes The Fill Cycle
If after selecting a cycle, the display reads FILLING and then advances to the heat up mode prior to giving you the C981 Error Code, then this is what you need to look for:
| Display/Symptom |
Cause |
What to Check |
Solution |
C981 (Select): POWER UP MODE
HI-LIMIT OPEN
UNPLUG / REPLUG UNITHigh-limit thermostat opened for at least 0.25 seconds during POWER UP mode |
Pressure leaking from chamber. |
Check for pressure leaks. Click Here To See "How To Find Pressure Leaks" |
Repair or replace malfunctioning component |
|
High-limit thermostat malfunctioning |
If error code does not reset... Perform High Limit Thermostat Continuity Test |
Replace High Limit Thermostat(s)
Click Here For M9 High Limit Thermostat(s) or
Click Here for the M11 High Limit Thermostat(s) |
|
Loose or damaged wire connection(s) |
Check wire connections at these locations: Wires From High-limit Thermostat Terminals to J5 on main PC board |
Secure, repair or replace loose or damaged connections |
|
Sterilizer is not level |
Be sure support surface (countertop) is level |
Place sterilizer on a level support surface (a countertop where the area the autoclave will be setting is level) |
