The autoclave displays H150 error

That “MPX Broken Now Leveling H150” message on the MOCOM Millennium B almost always points to a pressure sensor or mainboard signal issue, not just a bad transducer.

Since you’ve already replaced the pressure transducer, here’s what I would check next:

• Wiring harness: The signal line from the transducer to the control board may be corroded, loose, or shorted—especially near the chamber base where moisture collects.

• Power supply stability: A fluctuating 5 V or 12 V line can cause those random readings (500°C, 9 bar, etc.). Verify with a meter.

• Main PCB fault: The A/D converter section on the control board may be damaged—common after a surge or steam leak. If all wiring checks out, the board likely needs repair or replacement.

• Ground connections: Make sure the chassis and sensor share a clean ground; floating ground can throw sensor readings way off.

I checked the power supply to the pressure transducer which gives 12.9 VDC with the help of multimeter. The pressure transducer has 3 terminals, OUT, GND and IN. The OUT and GND shows 5V. Also, there is an A/D converter IC ADS8344E which I also checked through multimeter and 5V is powering this IC. I have checked almost every IC with a multimeter and finger, not heated and normal 5Vdc is powering them. The same error "H150" is shown when I remove the transducer connector from the control board.

Now what should be done to fix the circuit?

Hey WaseemKhan,

Is there any rust happening in or around the main board? I'd check to make sure the control board has a good GND. Really funky things can happen when the logic doesn't have a good GND. 5V on the pressure transducer GND leg in reference to chassis GND says something isn't right.

Good Luck

Hello sir, I have cleaned the board and there is not rust on the terminals. Actually the GND connections looks good because I have checked it through multimeter. Moreover, the GND is not giving 5V, it is giving 5V with the OUT pin of the pressure transducer. If you could send me your email address, I can't send you the images in this forum.

Thanks and regards

Hi Wassemkhan, Do You have a service manual?

Yes I have the service manual but it doesn't have the complete schematic of the control board. The error messages are fully described in manual. But it seems their is some technical problem in the control board.