HCV and six pack - Printable Version
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HCV and six pack - Keith Jordan - 10-05-2017
While at newell # 390 was pulled in to alignment pit and the passenger side hcv was dumping air.When air dropped below 90 psi leaking or exhausting stopped.Replaced hcv with one I had on board that Richard suggested I carry with me.Same result.Newell folks are not fans of this hcv so a Newell plastic bodied one was installed.Same result.After much head scratching cussing and discussion Mike a service writer came to the rescue.He observed the problem for about 10 minutes and proclaimed the driver side rear up solenoid needed to be replaced.This was on a Thursday about 4:30 pm.I had a motorcycle race I was competing in the following day 2 hours away.Needless to say I am having visions of not making the race and staying in God's country 3 more days at minimum.My understanding of the air system told me that Mike's idea was not the answer.I was wrong( as usual).The solenoid fixed the problem.I still do not understand that.Big props to the staff at Newell for staying 45 minutes after 5:00 pm on payday to get me on my way.I meet Bill( Bikestuff) and Mike( LandYachts) while I was there.Nice guys.Enjoyed the wisdom you shared with me.
RE: HCV and six pack - encantotom - 10-05-2017
You will find a post on here explaining the same thing I had and it was a ruptured drivers side up solenoid valve. I have had it happen twice
Tom
RE: HCV and six pack - Richard - 10-05-2017
Wow, after you left Miami, Mike @"Land Yacht" had the exact same issue.
First thing to understand is that ALL air to and from the airbags originates at the six pack. Each bag is tied into a common header in the six pack. The solenoid valves tie into that internal header. The HCV ties into the internal header when the travel mode is activated. Otherwise the HCV is isolated from the header and therefore the bags.
In level mode, the appropriate solenoid will either add air to the header, or let air out of the header.
In your case, and in Mike's and Tom's, the coach is in travel mode, therefore the travel solenoids are open and the HCV is trying keep the coach at ride height. Remember the HCV supply is not from the six pack, although the HCV output goes to the six pack internal header. Except, if the raise solenoid is stuck or leaking, air is being supplied to the header through the leaking solenoid. This raises the coach, and the HCV sees the coach is too high and trys to let air out to keep it level.
If the lower solenoid were leaking, then air would be exhausting out the back of the six pack, instead of at the HCV.
RE: HCV and six pack - Keith Jordan - 10-05-2017
(10-05-2017, 12:47 PM)Richard Wrote: Wow, after you left Miami, Mike @"Land Yacht" had the exact same issue.
First thing to understand is that ALL air to and from the airbags originates at the six pack. Each bag is tied into a common header in the six pack. The solenoid valves tie into that internal header. The HCV ties into the internal header when the travel mode is activated. Otherwise the HCV is isolated from the header and therefore the bags.
In level mode, the appropriate solenoid will either add air to the header, or let air out of the header.
In your case, and in Mike's and Tom's, the coach is in travel mode, therefore the travel solenoids are open and the HCV is trying keep the coach at ride height. Remember the HCV supply is not from the six pack, although the HCV output goes to the six pack internal header. Except, if the raise solenoid is stuck or leaking, air is being supplied to the header through the leaking solenoid. This raises the coach, and the HCV sees the coach is too high and trys to let air out to keep it level.
If the lower solenoid were leaking, then air would be exhausting out the back of the six pack, instead of at the HCV.
(10-05-2017, 12:47 PM)Richard Wrote: Wow, after you left Miami, Mike @"Land Yacht" had the exact same issue.
First thing to understand is that ALL air to and from the airbags originates at the six pack. Each bag is tied into a common header in the six pack. The solenoid valves tie into that internal header. The HCV ties into the internal header when the travel mode is activated. Otherwise the HCV is isolated from the header and therefore the bags.
In level mode, the appropriate solenoid will either add air to the header, or let air out of the header.
In your case, and in Mike's and Tom's, the coach is in travel mode, therefore the travel solenoids are open and the HCV is trying keep the coach at ride height. Remember the HCV supply is not from the six pack, although the HCV output goes to the six pack internal header. Except, if the raise solenoid is stuck or leaking, air is being supplied to the header through the leaking solenoid. This raises the coach, and the HCV sees the coach is too high and trys to let air out to keep it level.
The reason it stops at 90 psi is that is the pressure it takes to keep the coach at ride height. When supply drops to 90, the air pressure on the raise solenoid side and the air pressure provided via the HCV reach equilibrium. The failed raise solenoid is no longer raising the coach, and the HCV is no longer trying to lower the coach.
If the lower solenoid were leaking, then air would be exhausting out the back of the six pack, instead of at the HCV.
Thank you for making it so even I understand.I will be going thru the rest of them with the tom rebuild kits.
RE: HCV and six pack - Land Yacht - 10-05-2017
Thanks for the explanation Richard! I have read it twice and after a couple more I should have full understanding :-)
I kept the old solenoid, and will rebuild it with the kit from Tom, so I have a spare on hand in the future.
Has anyone remounted the front 6-pack inside the compartment instead of leaving it under the coach exposed to elements? The Newell Techs said the new coaches have the 6 pack inside the compartment not outside.
I also experienced another air ride anomaly when leaving Newell. The Tech that pulled my coach out made a sharp turn causing the coach to lean, then turned off the engine without allowing the coach to level. Thus, when I started it later and was walking around for my pre-flight check air was exhausting out the drivers side rear HCV. I thought I had another problem, but Creslie told me that happens when you don't let the coach level before turning it off, and it would correct itself when I got on level ground, which it did. Richard, can you explain what is happening in this situation?
RE: HCV and six pack - encantotom - 10-06-2017
i went through the same thing. was convinced it was a ride height valve and changed it. then that didnt fix it. it does make total sense why it was the solenoid valve. it is as was said. the raise solenoid is leaking air through when it shouldnt so it is putting air in the bag. when the bag is inflated it raises the rear and now the hcv knows it should let air out to level it, but air is coming in as fast as it is letting out. i had it happen on the passenger rear. then the next year it happened again on the front when i was sitting in my front yard getting to leave for a trip. i recognized the symptoms, and in 10 minutes had changed the valve out and was off.
with mine, i had bought a number of years ago an hwh manifold on ebay that had 6 valves on it. so i used them. they were totally different design than the ones we use but they fit. the plunger was hollow and the seal would actually rupture and let air through it. that little seal looked like it had blown up. i will no longer use that style of valve. ours are very different. ours gets a crease in it so air leaks by. or a failure with the spring is possible, but not likely. our valves are normally closed and are only open and letting air through when the coil is energized. so in the case of the travel valves, the coil is energized when you are in travel mode, so when you are driving mostly. if a coil was to fail from overuse, it would most likely be a travel one. but they are meant to last forever.
there is much discussion on this forum about why they fail. i would guess at this point i have probably looked at more of them than most folks and i am of the feeling that it is contamination in our air tanks and air system, mostly particles of rust. the seals in those plungers just doesnt deteriorate on its own with our modest use. these things are designed for much more harsh service than we give them, but that harsh service is usually in very clean air systems.
the rebuild kit makes them like new. new spring new o rings and plunger with seal.
tom
RE: HCV and six pack - Land Yacht - 10-06-2017
Tom your explanation of contamination makes sense. Here is the crazy story of my coach... I purchased right at 1 year ago. As I learned about the air systems. I realized the main air tank by the 120v compressor was installed upside down, meaning the drain valve was on top. When we recently pulled the tank to correct the situation, we found a little air in a water tank :-( it was only 2 weeks after correcting the air tank install that the solenoid failed. I have not rebuilt it yet, but suspect rust as you said.
RE: HCV and six pack - encantotom - 10-06-2017
a number of folks have had to replace different air tanks on their newells after they have rust out. it is for sure a real problem.
tom
RE: HCV and six pack - Richard - 10-07-2017
"I also experienced another air ride anomaly when leaving Newell. The Tech that pulled my coach out made a sharp turn causing the coach to lean, then turned off the engine without allowing the coach to level. Thus, when I started it later and was walking around for my pre-flight check air was exhausting out the drivers side rear HCV. I thought I had another problem, but Creslie told me that happens when you don't let the coach level before turning it off, and it would correct itself when I got on level ground, which it did. Richard, can you explain what is happening in this situation?"
Mike, this one is way more simple than the leaking raise solenoid. When the coach leans, you will notice if you look at the rear tires that one side is lower and one side is higher than normal. The HCV being a simple device that works solely based on the distance from the axle to the coach frame, sees the high side and lets air out to bring it down. The low side is letting air in to raise that side, you just don't hear it. Of course as soon as you get the coach out of the turn, all goes back to normal.
RE: HCV and six pack - 77newell - 10-07-2017
With the coach not level and the ignition immediately turned off, the 6-pack solenoids all close and lock that situation in. Upon restart the HCVS continue doing what they would have done had the ignition been left on. You can air me now or air me later - a quote from a real airbag.