Air Minder question

[lorim]

This is probably one of those dah questions but I have to ask because I honestly don't know.
Last year I bought a used Winnebago, 5.9 Turbo Diesel, Commons and had no idea when anything was last serviced so we did the basics and the little air minder read that the filter needed changed, just turning 60K miles so sure why not do this too. I reset the little minder and we've had the MH out a few times, the minder is all the way back up to the top reading like it needs changed again. Is this thing broke/junk, did I do something wrong when I reset it or do I actually have an issue I need to be concerned about?

[LJowdy]

Unless you're traveling exclusively on dusty roads, the filter-miner is worthless. I change my air filter every 3 years regardless of what the filter-miner indicates. In my opinion, For the most part, they're worthless.

[Milford 47]

A high vacuum should be all that pulls the indicator to the change position.

Many of us still have vacuum gauges around from the old days and it is easy to pull the tubing and measure the vacuum.

Given how cheap they are just replacing it is an option.

Usually it is the opposite problem, no indication due to leaks or a mouse biting the tubing and so on and a filter is run to long.

[A Traveler]

A diesel engine does not generate any vacuum. The intake air path is completely open, unlike a gasoline engine that has the throttle butterfly valve in the intake air path.
If the air filter is really plugged with dirt there will be slightly lower air pressure in the intake air path due to the restrictions in the filter, but it’s not a vacuum.

[lorim]

Thanks for the education, this does make me feel a lot better! I may replace it, but its not at the top of my to-do list anymore.

[lwmcguire]

A vacuum occurs when you have a negative pressure less than atmospheric

The differential across a filter creates the negative pressure that the filter minder monitors

If you're looking at truly accurate reading you have a filter restriction you need to verify with a new filter minder or a gauge

All internal engines either have a vacuum or a blower to get air for combustion

Filter minder is a differential psig indicator due to the negative psigdown stream which being a vacuum since it is less than atmospheric

[lwmcguire]

al-indicators-gauges/air-filter-restriction-monitoring-gauges-indicators/air-filter-restriction-monitoring-gauge-remote-mount.html

[palehorse89]

Originally Posted by lwmcguire

al-indicators-gauges/air-filter-restriction-monitoring-gauges-indicators/air-filter-restriction-monitoring-gauge-remote-mount.html

What

[Gary RVRoamer]

A diesel engine does not generate any vacuum.

Sure it does. If there was no pressure differential, how would air enter the cylinder for combustion on the intake stroke? The lack of a throttle plate in the diesel means no engine braking when the fuel flow stops, but the piston still sucks air in. Modern diesels usually have a turbo or supercharger to help the air intake, but they still run without it. An Onan diesel generator, for example, has no turbo.

[twinboat]

Correct. A turbo or super charged engine will have very little or no vacuum at idle after the turbo or super charger, but plenty between the turbo and air filter.

Naturally aspirated engines ( Non Turbo or Super charged ) will have vacuum at the intake manifold.

Engines, gas or diesel, are big air pumps, pulling in air, adding fuel and combustion, and pushing it out under higher pressure.

[Milford 47]

How It Works
The Filter Minder® Remote Mount gauge is a graduated gauge which monitors engine air filters. The position indicator progressively fills the window as air filter restriction increases, locking at the highest restriction. The air filter should be changed when the position indicator reaches the red zone.
The Filter Minder® should be reset whenever the service indicator is checked to determine air filter restriction or when a new air filter is installed. Push the reset button at the end of the service indicator, and the position indicator will return to zero.

Series
136501R
Mounting
Mounts in a convenient location for good visibility. Air cleaner fittings, vacuum hose, and mounting screws are available. See Accessories / Related Products.
Specifications
Vacuum Indicator (differential and pressure available)
Locking Type (non-locking is available)
Operating Temperature: -40 to +250°F (-40 to +121°C)
Accuracy: ±10% at red zone
Material: Polycarbonate housing
Standard Calibration: 8-35" water vacuum (2-8.7kPa) at the red zone
Dimensions
Length: 82.2 mm
Diameter: 59.9mm

[Milford 47]

Originally Posted by palehorse89

What

sometimes on the phone things just don't copy and past like you want

contents poste below with specs and specs on the vacuum range

[Jyrocharlie]

On my son's rv, the minder always showed red after it was driven, even with a new filter. We found out the opening on the side where the air pipe goes to the filter, is under size for the turbo airflow. It was causing enough vac during boost that the minder would turn red. We found it by removing the cover to the filter, the filter was still connected. The only thing disconnected was the lid. It eliminated the plastic pipe to the side where the air intake was. It had Never had as much boost and ran much better.
The RV was a 93 Gulfstream. The minder never turned red with the lid off.