Man Engine Gauge "air pressure after filter" question

Combination purposes I think.
Air filter restriction.
Altitude air pressure.
Alarm system between air in and boost pressure after turbo.
Maybe more.

I would think a large negative value is bad, like dirty air filters.
I like Zero.
I would think a positive number is either read in error (didn't see the minus sign) or the system needs zero calibration.

However, the computer is in charge of all of these values. if it runs, nothing is broke.
Go Fishing, it's pretty down there today and I've seen the fireworks in your hood. Have fun.

,ralph

It's the sensor right after the air filter. It indicates a dirty air filter and when it's time to clean it, OR if there is another air flow restriction before the air filter, such as the engine room vents not being adequate...…..they usually run -2 to -4 on all of the MAN boats I've ever run. Occasionally these sensors do go bad (like every 10 years), OR someone got overzealous with the air filter oil and it ruined the sensor. Zero is perfect as you have zero restriction.

It measures vacuum downstream of the air filter. A greater negative # equals a dirty air filter. IIRC it alarms at -1.5bar. Here's a pic of mine with freshly cleaned airseps.