How often should motorhome release air?

[Stump Jumper]

How often should my motorhome be releasing air. Mine seems to do the quick puff about every 20 seconds. Is this normal or should it be less frequent?

[wrongwayknt]

The motorhome or the Driver?!? Sorry...Couldn't resist!

[Stump Jumper]

Believe me, it's not the driver, it's the 14 year old son...

[Gary RVRoamer]

That is definitely not normal. Mine rarely gives a "puff" once the suspension is fully aired up unless I use the brakes or the coach shifts position (tilts). My guess is you have a leak in a suspension airline and the puff you hear is a result of the air compressor recovering from a low pressure condition. Each time the compressor recharges the air tanks, it ends with a "puff".

[Pusherman]

It will release air each time the compressor brings the coach up to full air pressure.

Every 20 seconds is excessive.

[BFlinn181]

Normally the only 'chuff' sound comes when the compressor has reached maximum pressure and it 'blows off' through the air dryer. If your's is cycling every 20 seconds, it sounds like a major leak!

[scgator]

The valve seat in the air governor is sticking; the most common culprit is "dirty" air from not draining the air tanks on a regular interval. This valve is adjustable for a high and low setting. It shuts off at "system pressure" and cycles the compressor on at the minimum setting. The puff you here is the system relief valve dumping excess air pressure once it exceeds the maximum set tank pressure.

I would strongly suggest having the air system flushed and drained to clean it out, because the compressor is continually running; that is why it is relieving every 20 seconds or so. air compressors are designed to cycle on and off as needed; if not corrected, air compressor life will be shortened dramatically. And that is expensive.............

[timex]

If it's blowing out of the over pressure valve on the air tank the governor on the air compressor is bad. If it's blowing out of the air dryer it needs rebuilt, which is more then just changing the filter. The desiccant in the filter breaks down and get into the valves of the air dryer causing the dryer to keep spitting off. Hope this helps.

[Craig_R]

If you are experiencing frequent air pressure releases at the air dryer, it is usually an indication of an air leak in the system. It has also been pointed out that you may have "dirty air". Sometimes just bleeding down the entire system will dislodge any dirt particles that may have got into the system. Restart the engine and bring everything back up to full pressure and if the frequent air pressure releases stop you will probably not be bothered by it again for some time to come.

The link below will take you to the procedures to perform the "Standard Air Brake Test". This is the same test that all holders of Class A & B CDL license holders with Air Brake Endorsements are required to perform each day. Everyone who operates a vehicle that is equipped with air brakes should know how to perform this test. It will indicate if there is an actual brake problem and help you to narrow down where the problem lies.

Inspecting Air Brake Systems

Pay particular note to section 5.3.3

Good luck

[Stump Jumper]

I have been under the motorhome while it was running and also after I shut it down. I can't hear any air leaks at all. When the engine is running it is definitely releasing from the air dryer.

[Craig_R]

Originally Posted by Stump Jumper

I have been under the motorhome while it was running and also after I shut it down. I can't hear any air leaks at all. When the engine is running it is definitely releasing from the air dryer.

I'm guessing that while you were out of and under the coach that the parking brake was set.

The fact that it is "Frequently" releasing from the air dryer is only an indication that something is amiss. Try this.

Park the coach on level ground.

Place wheel chocks both in front of and behind either drive wheel.

Start the coach and let the air build to full pressure.

Shut the engine down.

Release the parking brake. (This will release the spring brakes and charge the "Emergency" side of the air brake system. There is no air pressure in the "Emergency" side until this is done.)

Get out and walk around the coach and listen closely for air leaks.

I'll bet you hear something now. If not, go back to my previous post and perform the entire Standard Air Brake Test. Particularly the tests having to do with "rate of build" and "governor cut in" and "governor cut out".

Let us know how you make out.

[rvjimmy]

It might not be the air drier, you might have a bad air govenor. Check your air pressure if it gets to high over about 120 maybe the pressure relief valve is popping off.If the air govenor doesn't shut off the compressor it just keeps pumping causing the pop off to discharge the high pressure. Jim

[Stump Jumper]

Thanks for all of the advice. I'll try to test it more tomorrow night after work. Will let you know how it turns out.

[USAFretarded]

could be just faulty overpressure valve on dryer. Had mine replaced twice in 35,00 miles. They sometimes get dirt in them.