Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: dke1955 on October 08, 2016, 09:36:48 pm
Title: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 08, 2016, 09:36:48 pm
When you don't know where to start you start at the beginning so here goes. Bought the coach May of this year. Took coach in for some repairs and warranty items. MOT informed me in doing the other requested repairs they discovered air system was not leveling and maintaining level properly. Took a while for MOT to rectify but eventually they said they discovered some "clay" in the lines...they pulled the tanks cleaned and stated the problem was resolved. MOT stated this was usually indicative of not changing the air dryer filter...which I had replaced before picking up coach in May. Coach has been to Arkansas twice since picking up in May. PRIOR to taking the coach in, when setting the coach to auto level I did notice that periodically the system would expel air...but NEVER did the compressor come on to add air to the system. Last week I picked up the coach...MOT still not done with warranty issues but I had to make this trip. Had one day to load up the coach....we leave on Thursday night boondock at Walmart. I park the coach, I do not level, I may have left in "trip" mode..turn off the ignition and hit the hay. Within an hour there is the LOUD noise of the compressor coming on and it ran and ran and ran....a good 5 to 7 minutes....this happened 2 or 3 times during the night. Woke me up every @#$%^&* time it came on....I was pretty mad and tired at 6 am with a 7 hour drive ahead of me. Get to the campground....hook up water, electric, engine still running....level the coach....put it on auto level(rapid blinking red light) and let the slide out....during the night...same thing....compressor comes on and runs for 5 minutes. When we leave and I pull in the slide ...at the end of the slide retract process the compressor comes on.....it never had done this before. I get home, I do not level the coach, I hit "dump" on the leveling system...dump all the air, then I go to the air drain valve ( the valve to let all moisture out of tanks...I guess..)...open that up and let more air out. SO now I am thinking NO air in the tanks, and leveling system is NOT active. Just went outside to help the wife bring in the groceries and hear the compressor in the coach running....again. I called MOT before leaving on my trip and spoke with tech who said the system may be trying to maintain pressure in the seal around the slide....I understand this is a possibility but the coach never did this prior to MOT working on my air system. Could a leaky part, newly installed valve, something MOT left undone be causing this issue????? I am not at all in anyway mechanical, so the knowledge all of you have would certainly be wasted on me. What I AM looking for is ideas to go to MOT with. I would love to find a link to how the air system works....is the leveling system independent of the brake system which is independent of whatever is maintaining a tight seal around the slide. I haven't got the foggiest idea of how the system works and therefore cannot speak intelligently about it or even sometimes understand what the tech at MOT is trying to tell me. Once again if y'all would be kind enough to offer suggestions as to what may be going on I would certainly appreciate any input...as I haven't a clue. Thanks everyone, Ride Safe dave
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Texas Guy on October 08, 2016, 10:36:17 pm
Dave,
It starts with the basic premise of "Air 101" If the compressor is running more than normal, you have a leak. Knowing that, it becomes a matter of finding the leak(s) and this can be a long, frustrating process, there are far more qualified people for leaks on the newer FT air system on here. Long time ago we used to mix up soapy water in a spray bottle and hit every fitting and line that was exposed where the soapy water did not land on something that it might do harm to, like the inside of the coach. If there is a leak you will see bubbles. Fix that and then move on to the next one. Perhaps MOT might have left something loose? This happens. A good place to start looking might in the area where they were working.
Good hunting,
Carter Nac-
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Bob & Vicki on October 08, 2016, 11:05:27 pm
Dave,
We just had some work done on our air system. Our mechanic checked for leaks, Then he replaced our Living Room slide bladder, Travel Mode Vales and Solenoids, also found a couple other leaks. After picking up our RV we traveled from FL to Asheville, NC where we stayed for 20 nights. When ready to leave we had 80 psi in front and rear tanks. Our auxiliary compressor comes on every couple hours for 5 to 7 minutes. At our next stop we leveled and put the slides out. We were told st MOT when we bought our RV to leave the engine on until leveled with slides out. Compressor comes on now and then, air is released now and then.
Before this we replaced our travel height valves and linkages (the rubber ends on the linkage were fatigued and would bend) and our air dryer but could not hold air pressure. We have now been advised to replace our dryer annually. Our previous RV was an Itasca on a Freightliner Chassis and we replaced the air dryer every year.
Hope this helps,
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Carol & Scott on October 08, 2016, 11:28:57 pm
Technical Help - HWH (http://www.beamalarm.com/foretravel-links/hwh.html)
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 06:12:11 am
When you don't know where to start you start at the beginning so here goes. Bought the coach May of this year. Took coach in for some repairs and warranty items. MOT informed me in doing the other requested repairs they discovered air system was not leveling and maintaining level properly. Took a while for MOT to rectify but eventually they said they discovered some "clay" in the lines...they pulled the tanks cleaned and stated the problem was resolved. MOT stated this was usually indicative of not changing the air dryer filter...which I had replaced before picking up coach in May.
Dave,
It's entirely possible the previous owner let the air dryer go too long. Once that clay/white powder (desiccant) gets into the system, it contaminates more than just the tanks - it can get into check valves and then can cause the symptoms of a leak. While it might not have behaved this way before the work (and I'm not saying there isn't a leak), it's possible the problem is migration of that desiccant that is still in the system if only the tanks were cleaned.
There are a few folks who have been through this; Jim McNeece has the most comprehensive posts with photos on the subject (that I can recall):
Desiccant powder in air system - anybody else with this experience? (http://www.foreforums.com/index.php?topic=18448.msg126709#msg126709)
when setting the coach to auto level I did notice that periodically the system would expel air...but NEVER did the compressor come on to add air to the system. Last week I picked up the coach...MOT still not done with warranty issues but I had to make this trip. Had one day to load up the coach....we leave on Thursday night boondock at Walmart. I park the coach, I do not level, I may have left in "trip" mode..turn off the ignition and hit the hay. Within an hour there is the LOUD noise of the compressor coming on and it ran and ran and ran....a good 5 to 7 minutes....this happened 2 or 3 times during the night. Woke me up every @#$%^&* time it came on....I was pretty mad and tired at 6 am with a 7 hour drive ahead of me.
The system actually does occasionally need to add air to level. Basically it first exhausts the high points and then, if it can't get level by doing that (safely - without torquing the body of the coach) it will then raise the low points. Leveling behavior is highly dependent on the levelness/slope of the site you're in. The system "wakes up" every 30 minutes when in level mode to check the status and will adjust level if necessary which could be any combination of exhaust and inflate. It doesn't sound like yours is trying to relevel when it runs (you can tell if it is by looking for yellow "low point" lights on the control pad when the compressor is running) since it's going for a longer time, but if it does need to correct the level frequently that could indicate a leak in the leveling system.
Quote
Get to the campground....hook up water, electric, engine still running....level the coach....put it on auto level(rapid blinking red light) and let the slide out....during the night...same thing....compressor comes on and runs for 5 minutes. When we leave and I pull in the slide ...at the end of the slide retract process the compressor comes on.....it never had done this before.
The compressor running related to moving the slide is a couple of things - bringing pressure back up in the slide bladder tank after the bladder was reinflated AND to pull vacuum to deflate the slide bladder so you can move the slide safely.
I get home, I do not level the coach, I hit "dump" on the leveling system...dump all the air, then I go to the air drain valve ( the valve to let all moisture out of tanks...I guess..)...open that up and let more air out. SO now I am thinking NO air in the tanks, and leveling system is NOT active. Just went outside to help the wife bring in the groceries and hear the compressor in the coach running....again. I called MOT before leaving on my trip and spoke with tech who said the system may be trying to maintain pressure in the seal around the slide....I understand this is a possibility but the coach never did this prior to MOT working on my air system.
If you have the leveling off and you have dumped air, then yes, if the aux compressor is running it is likely trying to pressurize the slide bladder system (you didn't open and leave open the slideout tank air drain when you opened the other tank drains, right?). Now, you can pull the inline fuse to the aux compressor to stop this behavior (it will only stop the slide bladder function of the compressor, not the leveling aspect), but best to only do this if your coach is under cover in case it's a leak in the slide bladder system where the bladder could deflate. And also realize you will need to put the fuse back in if you want to move the slide because you'll usually need the compressor for deflation and inflation of the bladder.
I am not at all in anyway mechanical, so the knowledge all of you have would certainly be wasted on me. What I AM looking for is ideas to go to MOT with. I would love to find a link to how the air system works....is the leveling system independent of the brake system which is independent of whatever is maintaining a tight seal around the slide. I haven't got the foggiest idea of how the system works and therefore cannot speak intelligently about it or even sometimes understand what the tech at MOT is trying to tell me.
The leveling and the slide bladder system are somewhat independent. As I mentioned above, you can dump the air and turn off the leveling, but the aux compressor will still operate to keep the slide bladder inflated. In fact, if you have a catastrophic leak in that system or in the unload (normally open) valve on the clear bowl mounted by the aux compressor, it will run and run and run. Since yours is only running 5 or so minutes, with hours in between, it doesn't sound like there is a major leak. There are a couple of places that a minor leak could occur in this system - the 1/4 turn valve(s) for the slide bladder(s) is a common leak point. Many of us have replaced them with ball valves from the air compressor department in Home Depot or Lowes. Another is cracking in the bottom of the clear bowl with the unload valve on it (although this will only present as a leak when the compressor is running since that valve is normally open and closes only when the compressor runs).
Now, in your 2002 do you also have the air awning? I believe that is also fed by the aux compressor in that year, but someone with a 2002 would need to explain how it is connected to the system. They might also be able to post an air schematic for that year (it might be different from our 2003, especially if you don't have an "air tank" switch in the group of rocker switches to the driver's left).
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 09, 2016, 09:52:54 am
It's entirely possible the previous owner let the air dryer go too long. Once that clay/white powder (desiccant) gets into the system, it contaminates more than just the tanks - it can get into check valves and then can cause the symptoms of a leak. While it might not have behaved this way before the work (and I'm not saying there isn't a leak), it's possible the problem is migration of that desiccant that is still in the system if only the tanks were cleaned.
There are a few folks who have been through this; Jim McNeece has the most comprehensive posts with photos on the subject (that I can recall):
Desiccant powder in air system - anybody else with this experience? (http://www.foreforums.com/index.php?topic=18448.msg126709#msg126709)
The system actually does occasionally need to add air to level. Basically it first exhausts the high points and then, if it can't get level by doing that (safely - without torquing the body of the coach) it will then raise the low points. Leveling behavior is highly dependent on the levelness/slope of the site you're in. The system "wakes up" every 30 minutes when in level mode to check the status and will adjust level if necessary which could be any combination of exhaust and inflate. It doesn't sound like yours is trying to relevel when it runs (you can tell if it is by looking for yellow "low point" lights on the control pad when the compressor is running) since it's going for a longer time, but if it does need to correct the level frequently that could indicate a leak in the leveling system.
The compressor running related to moving the slide is a couple of things - bringing pressure back up in the slide bladder tank after the bladder was reinflated AND to pull vacuum to deflate the slide bladder so you can move the slide safely.
If you have the leveling off and you have dumped air, then yes, if the aux compressor is running it is likely trying to pressurize the slide bladder system (you didn't open and leave open the slideout tank air drain when you opened the other tank drains, right?). Now, you can pull the inline fuse to the aux compressor to stop this behavior (it will only stop the slide bladder function of the compressor, not the leveling aspect), but best to only do this if your coach is under cover in case it's a leak in the slide bladder system where the bladder could deflate. And also realize you will need to put the fuse back in if you want to move the slide because you'll usually need the compressor for deflation and inflation of the bladder.
The leveling and the slide bladder system are somewhat independent. As I mentioned above, you can dump the air and turn off the leveling, but the aux compressor will still operate to keep the slide bladder inflated. In fact, if you have a catastrophic leak in that system or in the unload (normally open) valve on the clear bowl mounted by the aux compressor, it will run and run and run. Since yours is only running 5 or so minutes, with hours in between, it doesn't sound like there is a major leak. There are a couple of places that a minor leak could occur in this system - the 1/4 turn valve(s) for the slide bladder(s) is a common leak point. Many of us have replaced them with ball valves from the air compressor department in Home Depot or Lowes. Another is cracking in the bottom of the clear bowl with the unload valve on it (although this will only present as a leak when the compressor is running since that valve is normally open and closes only when the compressor runs).
Now, in your 2002 do you also have the air awning? I believe that is also fed by the aux compressor in that year, but someone with a 2002 would need to explain how it is connected to the system. They might also be able to post an air schematic for that year (it might be different from our 2003, especially if you don't have an "air tank" switch in the group of rocker switches to the driver's left).
WOW...thank you for this information....just what I was looking for...would you know where the fuse to stop the compressor from inflating the bladder is located? I do not have an "air" awning but I do have an "air tank" switch to the drivers left and have always wondered what that was for....is it only functional if you have an "air awning" or does it also serve another purpose??
Thanks again for all this information...tremendous.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 10:54:49 am
Dave,
Typing on my phone so short sorry. Look for fuse in power line going to compressor near compressor. Small rectangular iirc. Air tank switch is n/c solenoid that when on opens line between aux compressor and big tanks to air then up without main engine running. You want that off unless you absolutely need to air up quietly since there isn't a whole lot of desiccant on the aux compressor to put dry air in the tanks.
Also, you can tell if that solenoid valve or its check valve is leaking through (i think it has one) if you watch the front and rear tank pressures on the driver info center with the main engine off when the aux compressor runs. If the switch and engine are off and the tank pressures rise, it's leaking through
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 09, 2016, 10:59:11 am
Michelle and Carol/Scott thank you for your replies...I will surely sleep better tonight. One more (or a couple) question if I may, since MOT indicated there was a "clay" like substance in the lines which needed to be removed, and after reading posts from Mr. Beam, Wolfe, and others it seems to me I should have the Haldex filter (desiccant filter) replaced ASAP. The coach is a 2002, and while I do have the service records of the coach I do not see any reference to the Haldex being replaced....ever... (Mr. Wolfe stated the Haldex should be replaced every 3 years). Your opinion? ......any idea on cost (but not really an issue....like a bad tooth...it's got to be done...from looking at pics of others I may be able to do this myself.
Also, since MOT cleaned the tanks I have noticed that previously the tanks would hover right around 90+ pounds never higher, now after the cleaning the pressure on both the front and rear tanks is about 120 pounds (at the upper end of the gauges hard to tell exactly what the pressure truly is), so I'm sure I am much better off...but evidently what I thought was "normal" wasn't...so the question is, what is a normal pressure for the tanks (anything over 90 is good?)? Thanks again, dave
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 11:06:26 am
Dave you mentioned air dryer being replaced when you bought the coach in may. That should have been the Haldex unit and a new or properly reman'd unit should have had a new desiccant filter. It doesn't hurt to replace it but just wanted to mention that.
This is on the main engine not the little desiccant bowl by the aux compressor.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 11:09:57 am
On A & B tank pressures, governor on engine compressor generally tells that to add air when pressures drop to 90 and cut out when they reach 120. They will vary as you drive and the system uses air, but should generally be between those readings when engine is running
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 11:21:48 am
Also check the tank drain valves themselves with soapy water. If they hadn't been exercised in a while and now you are, they can leak a little
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 09, 2016, 11:33:05 am
We just had some work done on our air system. Our mechanic checked for leaks, Then he replaced our Living Room slide bladder, Travel Mode Vales and Solenoids, also found a couple other leaks. After picking up our RV we traveled from FL to Asheville, NC where we stayed for 20 nights. When ready to leave we had 80 psi in front and rear tanks. Our auxiliary compressor comes on every couple hours for 5 to 7 minutes. At our next stop we leveled and put the slides out. We were told st MOT when we bought our RV to leave the engine on until leveled with slides out. Compressor comes on now and then, air is released now and then.
Before this we replaced our travel height valves and linkages (the rubber ends on the linkage were fatigued and would bend) and our air dryer but could not hold air pressure. We have now been advised to replace our dryer annually. Our previous RV was an Itasca on a Freightliner Chassis and we replaced the air dryer every year.
Hope this helps,
Did you ever notice compressor coming on immediately after bringing in the slide? I'm starting to think I have a bladder/solenoid issue which may be leaking. Thank you for your reply...I really appreciate it. dave
On A & B tank pressures, governor on engine compressor generally tells that to add air when pressures drop to 90 and cut out when they reach 120. They will vary as you drive and the system uses air, but should generally be between those readings when engine is running
Great..thank you....so I now seem to be at the upper end of normal. I guess the problem for me is I just have no idea what to expect, or know what is going on, what is normal, what is abnormal...case in point the tank pressure...even though I was at a safe pressure (90 lbs) prior to taking the coach to MOT when I got coach back and I read 120 lbs I'm thinking "is it time to panic, am I going to blow a line, am I better off or worse off", and this now extends to the problem with the compressor running..."am I going to burn up the compressor, is this NOW normal because after the MOT repair it is happening and it wasn't before I took it in....maybe what I thought was normal was in fact a problem...and on and on. I don't know about many of you but for me at times this gets to be a little overwhelming....not being a big baby here but I am talking about a substantial investment....both in time and money.....that I bought to enjoy not to worry and think about day after day. My biggest concern is not knowing about the systems that affect the safety of the coach....air being my biggest concern since I know absolutely nothing about it and it affects the brakes (which I understand will lock if the pressure drops below 60 pounds). I always check tire pressure, oil level, transmission level, before taking off but there is still the element of concern that I may not be aware of something or checking something I need to or should have checked...again from time to time it is a bit daunting....maybe this is normal...maybe this is what the man at the last campground meant when he said, "welcome to rv'ing!" ...... Again thanks so much for taking the time from your day to reply....I DO appreciate it. dave
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 09, 2016, 11:35:26 am
Also check the tank drain valves themselves with soapy water. If they hadn't been exercised in a while and now you are, they can leak a little
Am I correct in that the wet tank is the only place to drain the air...? I am off to check for leaks again as I post this...I did not know the front and rear tanks have a drain valve.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 11:38:35 am
Dave,
The aux compressor coming on immediately after extending or retracting the slide is normal. It's the system replacing the air in the tank that was used to reinflate the bladder. It world run a long time if there was a slide bladder leak.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 11:40:11 am
Front rear and slide tank drains should be petcocks in the front driver side wheel well
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 09, 2016, 12:10:27 pm
new development....at the coach to check wet tank line for leak....I opened valve on the wet tank and more air escapes...but as I stated when I parked the coach last Monday I drained the wet tank to the point no air was coming out. Also, when I closed the door to the coach I heard air release....opened the door to be sure I heard what I heard and it happened again.....did this several times....same thing...air is releasing somewhere...is this the step trying to retract....but it shouldn't cause coach is off....what the heck?
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: RRadio on October 09, 2016, 12:40:39 pm
After over four years of full timing I've only got three remaining air leaks that I'm aware of. I've found and fixed a gazillion of them over the years. Be realistic about your expectations. You're not gonna drive a new coach from TX to AR and find / fix all the air leaks in the entire system! hahaha ...of course I thought exactly that same thing when I bought my coach and probably everyone else on this forum did too.
Turn the compressor off and notice which air gauge goes down quicker. Pull out your pneumatic drawing and see what's on that system. Soap suds test everything you can get to on that system, especially the fittings. Make a list of leaks and fix as many as practical. Pay attention to which side your coach leans toward first as the air pressure drops. If you don't have any leaks in the fittings for the leveling system for the side that drops first you should probably suspect the leveling valve is leaking internally. Unless it drops rapidly I'd live with it. I replaced the two rear leveling valves on my coach and now I can go nearly a week before I turn the electric aux compressor on. If only one leveling valve is leaking try to park in a place where that valve will be all the way up or all the way down. They usually only leak when they're somewhere between all the way up or down. They'll usually leak at one particular height more than any other height. I have the manually adjustable leveling valves but I'm willing to guess the automatic valves are about the same. If one of your airbags is leaking the side of the coach that has the leaking airbag is gonna go down very quickly and you'll hear the air hissing out of the airbag, so basically you'd know if an airbag was bad.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: RRadio on October 09, 2016, 12:43:13 pm
When you walk from one end of the coach to the other it will level itself and release air from one leveling valve while adding air to the opposite leveling valve. This is normal. Turn your aux compressor off and it'll stop doing this after the air pressure goes down to about 60 psi... Don't worry, be happy! :)
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Neal Pillsbury on October 09, 2016, 01:36:59 pm
Front rear and slide tank drains should be petcocks in the front driver side wheel well
Michelle/Dave, Differences in coach models and years may be tripping you up: 2002 front and rear brake air tanks as well as the HWH aux air tank have only tank located drains (as far as I know). Like all other FT's, the 2002 U270, U295, U320's have the wet tank drain fitting in front of the street side duals. I think that the 2003 model year Unicoach, though, was the first year to OEM install remote (rear, front and aux tank) drains in front of the street side steer tire. Many owners have installed tubing extensions, aftermarket, to make the drain petcocks more user friendly, so hard to tell what might be there. HTH, Neal
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 09, 2016, 05:01:33 pm
Michelle/Dave, Differences in coach models and years may be tripping you up: 2002 front and rear brake air tanks as well as the HWH aux air tank have only tank located drains (as far as I know).
I think that the 2003 model year Unicoach, though, was the first year to OEM install remote (rear, front and aux tank) drains in front of the street side steer tire.
Thanks Neal, I didn't realize that was a 2003 model year change. What a pain in the butt not to have the remote drains.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: RRadio on October 09, 2016, 05:15:16 pm
Those drain valves leak pretty often, and the only one you should ever need to use is the one in the bottom of the wet tank. I replaced the leaking drain valves in the bottom of both dry tanks with pipe plugs to get rid of those leaks permanently. The drain valve in the bottom of the wet tank is remote, and it leaks a little, but I decided to leave it because that's the best possible place to have a leak. It basically guarantees I'll never have any moisture in the bottom of the wet tank. My original wet tank rusted out because the previous owner never drained it so I replaced the tank a couple of years ago. I drive my coach often and never get any moisture out of the wet tank drain. The previous owner didn't drive it for at least three years before selling it to me. Even if you never drive your coach you shouldn't get any moisture out of the dry tanks if you drain the wet tank periodically. If you install a moisture separator on your electric aux compressor you shouldn't get any moisture in the system even if you never drive it or drain it... This is just in theory of course, and I wouldn't suggest testing the theory. :)
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: red tractor on October 09, 2016, 05:48:29 pm
Sounds like some one has wired the switch for the step to be powered up at all times, to close the steps when the door is closed. so could have leaking cylinders on the step.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Tim Fiedler on October 09, 2016, 06:00:13 pm
Step well cover air cylinder NOTORIOUS for leaking as well...
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 10, 2016, 12:10:56 am
Michelle/Dave, Differences in coach models and years may be tripping you up: 2002 front and rear brake air tanks as well as the HWH aux air tank have only tank located drains (as far as I know). Like all other FT's, the 2002 U270, U295, U320's have the wet tank drain fitting in front of the street side duals. I think that the 2003 model year Unicoach, though, was the first year to OEM install remote (rear, front and aux tank) drains in front of the street side steer tire. Many owners have installed tubing extensions, aftermarket, to make the drain petcocks more user friendly, so hard to tell what might be there. HTH, Neal
As far as I can tell....and believe me I looked...drivers side in front of the duals is labeled as the wet tank drain valve location....found no other drain valves in the wheel wells....so I just have one.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: dke1955 on October 10, 2016, 12:11:27 am
When you walk from one end of the coach to the other it will level itself and release air from one leveling valve while adding air to the opposite leveling valve. This is normal. Turn your aux compressor off and it'll stop doing this after the air pressure goes down to about 60 psi... Don't worry, be happy! :)
How do you turn aux compressor off?....by pulling fuse as Michelle stated above or is there a switch other than the rocker switch beside driver?
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Carol & Scott on October 10, 2016, 01:01:56 am
Dave -
In reading this thread it appears to me that your are in unchartered waters to you. If I am wrong in this assumption please disregard what follows.
Please slow down and try to focus on one thing at a time. I am not saying this to be critical of you. I think it is safe to say that most every owner on this forum has experienced what you are now experiencing. Me too. The coach in it's entirety is complicated and can be overwhelming. One thing at a time. ;)
You must find your Air Schematic in your white Owners Manual. The drawing will be in the back. If you do not have a White Owners Manual, let us know and one of us can send you a digital copy. I think.
Start by locating your Aux. Comp. on the drawing and then in your basement. If your Aux. Comp. is always running locate the fuse holder and pull the fuse. Single 12volt wire attached to the compressor motor assembly.
You have 2 air compressors. One is attached to the engine and only operates when the engine is running. The other is the Aux. Comp. and provides air to your air bladders and the HWH leveling system when your engine is not running. They both influence each other. Separate systems that control mostly the same stuff.
Starting with your Aux. Comp. running you must track down leaks in your system. With the aid of a bottle of soapy water and your HWH Air schematic you can see and follow the lines to the bladders and the leveling six packs. The air lines are numbered and match the numbers on the schematic.
I have attached a link to the HWH On Line School. These pages are in Adobe PDF format (http://www.hwhcorp.com/ml44100b0_schools.html)
Start to read. It will explain how the air and hydraulic systems work. You will also find links to their Technical Papers/Manuals that are more detailed than the on line school and are written by system type/year.
You must Identify and address one problem at a time.
Please Note: If you attempt to go under the coach to track leaks, which you will, you must use safety blocks. Use the SEARCH button at the top of the page and SEARCH "Safety Blocks". Read the threads and do what is recommended. It is very dangerous to get under your coach without these blocks. Some have been seriously injured by Not following safety procedures.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Michelle on October 10, 2016, 06:22:51 am
As far as I can tell....and believe me I looked...drivers side in front of the duals is labeled as the wet tank drain valve location....found no other drain valves in the wheel wells....so I just have one.
Dave, When you get under the coach, you will see that you have four drain petcocks: the front, rear and aux. air tanks, located above the front axle, use the same style drain petcocks (as used on the the wet tank). Its just that the front three petcocks are screwed directly into the bosses on the tanks while the petcock on the wet tank has been extended, using brake air line tubing, from the wet tank boss fitting down to its location in front of the street side duals.
If you find water or dust expelled from your wet tank drain, you should suspect that you are overdue for engine driven air compressor air dryer service/replacement. If you find water expelled from your aux. tank drain, you should suspect that your aux compressor desiccant needs to be replaced. If you find water or dust expelled from the front or rear air brake tanks, the urgency for alarm needs to go way up as that means the need for air system service is far overdue. In freezing weather, it also means there is a high probability that your brakes will not function properly. Neal
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: tothetrail on April 30, 2017, 12:39:40 pm
Dave, did you ever find a resolution?
I'm experiencing some of the same symptoms, but they seem to only be exacerbated by cold weather, usually below 40 degrees. During the warmth of the day that compressor runs way less frequently, if at all.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: AC7880 on May 01, 2017, 12:54:39 am
I'm experiencing some of the same symptoms, but they seem to only be exacerbated by cold weather, usually below 40 degrees. During the warmth of the day that compressor runs way less frequently, if at all.
Same thing happened to me. Slide bladder leak in my case, worse when cold out. Go outside, and listen and feel all around the slide bladder(s)
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: tothetrail on May 01, 2017, 01:56:00 pm
Same thing happened to me. Slide bladder leak in my case, worse when cold out. Go outside, and listen and feel all around the slide bladder(s)
Will do, thanks!
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: Roger & Susan in Home2 on May 01, 2017, 02:01:43 pm
Jennifer, your year should have a turn valve for each bladder that isolates it from the air system. Once it is inflated, close the valve. If it is the bladder the pump should stop cycling. If it does not then the leak may be somewhere else. I added a pressure gauge and valve for the bladder. I know when it is inflated, I can shut the valve and make sure it holds pressure. I also added a pressure gauge to the HWH tank.
Title: Re: Air compressor comes on frequently and runs for 5+ mins
Post by: tothetrail on May 01, 2017, 02:05:55 pm
Jennifer, your year should have a turn valve for each bladder that isolates it from the air system. Once it is inflated, close the valve. If it is the bladder the pump should stop cycling. If it does not then the leak may be somewhere else. I added a pressure gauge and valve for the bladder. I know when it is inflated, I can shut the valve and make sure it holds pressure. I also added a pressure gauge to the HWH tank.