Seems like air leaks are a popular topic these days. I have been pursuing air leaks on my 2015 IH45 for nearly 2 years. Although its a bit like "whack-a-mole," I have been able to make good progress--mostly by spaying lots of soapy water to find and replace air lines and connectors. Reference the attached pic--I found my final big leak [maybe?]. The check valve that isolates the aux. pump from the Active Air tank failed--totally rusted inside. Seems the desiccant bulb on the aux. pump doesn't do a very good job of removing moisture. Issue was likely made worse by previous system leaks that caused the pump to run a bit more than usual.
The very first air leak I found on my coach was the top fitting on that check valve. Since I still seem to have some leaks, I guess I need to go and remove that check valve and verify it is working or I guess better yet just replace it.
PS--the tricky part with this check-valve leak is that the air leaked back internally thru the aux. pump so there were no external signs of the leak--and it was a pretty sizeable leak too.
On the subject of check valves, I'm confused about the variety of types and costs of the various check valves that are available. Can anyone shed some light on what should be taken into consideration when selecting the proper check valve and what would justify the huge price differences? See examples attached.
It's a small load of desiccant for the overall job, particularly in humid conditions. How often are you replacing/re-drying and re-using it?
The short answer is never in the two years I have own the rig--engine drier yes; this drier nope. Fully appreciate the need to service the engine drier but haven't messed with the pump drier--didn't really think about it/nobody mentioned it. This does beg the question, though, as to whether the aux. pump desiccant system in the 2003 era FT is different from the one in the 2015IH? The one on the 2015 looks more like a small filter in the bulb and appears totally inadequate to the task of drying the aux. pump air volume.
PS--Geomann--I asked the same question on pricing after my research. Though, both Wabco and Haldex are recognized air brake suppliers. Fleetpride also found a Bendix cross-ref number for me--but no price. The first valve on your post looks a bit like the OEM in mine rig, except mine is female to female; the second is an apparent match; the third looks like brass--good for moisture; and the fourth looks like any number of valves on Amazon and Ebay???
A 2003 has about a 4 ounce (IIRC) capacity. There are indicator crystals that change color as the desiccant is spent, at least with the usual load. It's readily available in bulk; just keep it dry. FOT used to charge $51/dose so I learned to "bag my own". You can find blue indicating, which has cobalt, or green indicating which does not.
We typically changed it out every couple of months, as needed. It can often be revived by baking/microwaving to dry it out so I kept a paint can of spent desiccant for "bulk drying".
Link to my "instructable" Desiccant option for the HWH system (https://www.foreforums.com/index.php?topic=12784.0)
Michelle--very interesting, my desiccant, if it is desiccant, looks more like a pre-formed cone--not too different from what you might see in a small fuel filter sediment bulb. My system also has a fancy electric solenoid dump valve that exhausts out the bottom of the bulb, every time the aux. pump shuts off? I will get a pic and attach it..
I thought I had a good picture of the filter but this is the best I have. Problem is you can not see the filter. Just so happens that FOT has the Air trap solenoid valve on sale. Maybe not since it says May Sales.
On the check valve I have sent Brad @ FOT if they stock. I guess I might find out tomorrow or maybe next week if he has taken a long holiday. I have not seen any except the $100.00 one that is not brass
See here if your system is similar to our former 2003 HWH Filters and Bowls (https://www.irvblog.com/foretravel%20projects/HWH-Filters/)
See also this on the NO solenoid "blow off" valve, which I believe is identical to the electric solenoid dump valve you mention. It has the same function; a 2003-ish has separate bowls for desiccant and condensate.
HWH Solenoid Valve Rebuild (https://www.irvblog.com/foretravel%20projects/HWH-Solenoid-Valve-Rebuild/)
Just purchased one from FOT (about$145).
It comes from HWH.
jack
If the issue is the valve seat, get parts (specifically the plunger) from encantotom and rebuilt the solenoid valve to have as a spare.
Michelle--just as I was starting to suspect after your last post--my 2015 system only has the clear bulb and "blow-off" solenoid, similar to what you have on the left. I dont have anything like the desiccant cartridge on the right. Almost seems like FOT abandoned the desiccant function in favor of the owner ensuring they periodically drain the Active Air tank. Problems here are: 1- the steel check-valve seen in your atchmt doesn't like the moisture; and 2- my aux pump feeds three functions: a-the active air tank; b-the aux tank; and a direct feed to the Active Air leveling system in the event the AA tank has emptied and the two DOT tanks are isolated by their protective valves [eg. at 60 PSI or below]. Think parked in a CG for several days, your stored air is depleted, and the AA is triggered to re-level the coach via the air bags.
Scout (I refuse to call you "old" ;) )
Some have retrofitted a larger payload desiccant vessel in their older coaches - it's basically an air dryer for a shop compressor. If you frequent humid/moist areas like the Gulf coast or PNW, it would probably be possible to plumb in something like that on your coach.
I do not know if we are hijacking this thread, but I have the same questions. I have to feel that a check valve is a check valve. I ordered two from Find it parts that appeared to be the same threads and size as my "original" check valves and a pop off valve for my wet tank. After I replaced the aux pump tank aka Slide bladder tank, I still had some substantial leaks. All I could find was the pop off valve on the wet tank leaking and it was draining the the two "front and rear" brake tanks. So both check valves appear to be open both ways. As I have removed sensors and valves I find that they have blockage and corrosion at the inlets. I feel my air system is pretty clean and dry NOW, but I am replacing parts damaged or blocked by twenty years of use or abuse. Now that I have direct and constant reading pressure gauges for both front and rear tanks, I can watch real time what is happening with my air. I also remoted the drain valve for the new Slide Out Seal Air Tank to make it easier to check air quality and drain moisture on a periodic basis. Also my original check valves had a part number on a label attached to each valve. This number was Meritor WABCO 9341990030 which Find it Parts shows a Haldex KN23000 as a direct replacement which is what I ordered at $28.84 each, Today they also show a Newstar 8444 as a direct replacement at $10.18 which I did not see earlier when I ordered the Haldex part. I am sure either on will be fine though. I do not know if I have answered your question, but I will let you know how the parts I ordered work out in a few days when I go back to the coach and install them.
Herb, the valves to isolate each slide bladder were leaker on my 01. They got replaced when I put vacuum pumps in to suck the bladders down.
Fot has check valve RN13526BR which is $63.53 + tax+shipping
Napa can match the check valves for about 40$.
You can find rebuild kits for most of the old ones.
Mine are female / male. Some replacements may need a nipple to fit.
Just an FYI - when I replaced the check valves on my U320 the new ones came with a "hum" as air was passing through them. Sounded like a harmonic imbalance. Not too loud or annoying, just a new sound. To this day you still hear them every time the coach starts airing up. Just an FYI if you start hearing a noise you aren't familiar with. They work fine and I've heard others report the same.
This has been a very enlightening post for me--it also reminds me that while older and newer Foretravels have a lot in common, there have also been some changes over the years. Think the engine compressor drier does a good job [if properly maintained] of controlling moisture, but without desiccant, the aux air pump can be a major source of moisture in the air system. Other than installing an after-market desiccant system, the alternative is to regularly drain off the tanks. There are also implications for replacement check-valves too--perhaps those made of brass [Haldex?] are a better choice.
PS--interesting comment about the "noise" some check-valves make--mine sound-off for a few seconds as the compressed air reaches about 60PSI. 60PSI is when the protective valves [isolation] open on the DOT tanks and begin filling the other tanks. Be interesting to understand what causes the noise?
I suspect it is similar to what makes the noise in a musical wind instrument that employs a reed.
Most check valves consist of a thin spring loaded flat metal plate that sits on a round seat. Air can only flow through the valve in one direction. As air flows through the valve, it lifts the thin plate up off the seat. At some specific rate of flow, the plate must start to vibrate rapidly on the seat, thus generating the weird noise.
Hey Chuck--ref the noise, that sounds right--I had the check-valve apart to clean up the rust, pending a replacement. The innards are exactly as you described.
Finally got around pulling my inline check valve above the compressor out and checked it. You could blow in either side and the same amount of air came out. I have now ordered a new one from FOT. I tried to open it up last night but was unsuccessful in doing. I was trying with a crescent wrench and valve in vice and it was not giving. Even tried hitting end of wrench with hammer. Today going to take a socket with my almighty impact wrench and see what happens.
I also got a picture of what our filter /air dryer looks like. I am not sure how I would go about being able to get to it since it is crammed between the inverter and air compressor. I had a hard time just getting a picture of it.
TurboJack, I also tried to disassemble the check valve to look into the possibility of rebuilding it and there's no way I could get it apart. I can't even tell for sure that it's two pieces although it must be. Please update if you're able to get it apart. In your picture, that's the water separator with automatic drain solenoid on the bottom. Our older coaches have that as the first stage of water separation and then we have a dessicant bowl filled with beads that change from blue to pink when they've been exhausted. Do you not have a dessicant filter at all on your system?
No, that is all that we have.
Me neither on my 2015 IH--mine is the same as Turbojack's --no desiccant. The FOT air system schematics list the assembly as a "water trap" with a "filter" inside. There is a blow-off solenoid at the bottom of the glass bulb that exhausts each time the pump runs and then shuts off. PS--I was able to open the chk valve and rehabilitate it--it's in two halves and has an O-ring to seal it. Inside is simple--a mental disk covered with a rubber material closes against a molded plate on one side, and a very weak spring on the other side. Again, my valve was full of rust with no movement of the disk.
You can see the "filter" in this write-up (and you can see how the bowl cracks due to thermal cycling and the "filter" corrodes over time). I'm reasonably certain the water separator bowl on our former 2003 is the same as your and turbojack's IHs have. We've seen a 2008 Nimbus with a catastrophic failure of that bowl.
HWH Filters and Bowls (https://www.irvblog.com/foretravel%20projects/HWH-Filters/)
The list of what I "don't know what I don't know" continues to go. The good news is that I have conquered most of my air leaks and for the time being, I am living in the "land of good enough!" Finding and fixing the check-valve was a major improvement for maintaining air pressure. What I don't know is where the air was going to that leaked back thru the chk valve. The "water trap," the 12v pump pressure switch, and another air line all tee into the manifold on the pump. There doesn't appear to be another check valve in sight. So, a leak-down in any of the aforementioned attachments to the manifold would, you think, cause the pump to start, eg, like when using the pneumatic doors, unless the HWH system ultimately controls power to the pressure switch and pump relay?
I had a air leak on the main slide bladder last year just before our trip to Alaska, Could not get in for repair at FOT, MOT or NMS so off to HWH on our way to Alaska.
HWH replaced the main slide bladder and serviced the Aux air system, one of the things the service manager mentioned was they stopped using the desiccant dryers and just added a second moister trap due to all the issue's caused by the desiccant dryers carrying trash into the valves and solenoids. One of the other things they found while servicing the Aux air system is the brass cross that is on the discharge of the aux. compressor has a built in check valve and was leaking the system off slowly causing the compressor to run. I was glad I had them leak check the system while having the bladder replaced. I would have never found that check valve built into the brass cross it was totally hidden.
So you are saying in this area circled in blue there is a check valve in there?
Geodmann, ref my post above, was able to separate the two halves--they are sealed with an o-ring but suspect yours is rusted shut. Simple insides--a small disk with a rubber covering on one side, weak return spring on the other. Rubber side of disk closes against a plate with a slightly raised ring for a sealing surface. Was able to clean up the rust and return the valve to function but will eventually replace it--perhaps with the Haldex brass version--might help with the moisture/corrosion issue from the aux air pump.
PS--Seem to have my air leaks under control, right now, but there are several of these check-valves thru out the air system. Again, if maintained, the engine drier probably does a good job of controlling moisture--but have to wonder what condition the other valves are in. My experience--the external leaks are easier to find and fix; the internal ones, not so much.
The above bolded comment jogged my memory. There was a service bulletin back in 2003 for this, but it was on "complaint basis", no owner notification:
Thanks, Michelle, you are great.
Who would have thought that what looked like a regular 1" +/- nipple had a check valve in it. I don't' think I have ever seen anything like that.
When I was looking at the air compressor setup I was always wondering where the check valve was that was keeping the blow-off solenoid from releasing all of the air from the tanks when it released the air/water from the bowl. I don't think mine is leaking there at the moment but it is possible it could be a small leak.
Just a reminder from a previous post while on the air subject, Milton air products still has a sale going, many regulators and fittings 80% off.
Quality stuff.
The plot thickens, at least for me. I had no idea about the additional check valve in air pump tee. Nor do I really understand what triggers the generic air pressure switch [gray box] attached to the tee. Know that my leak downs reduced significantly when I rehabbed the aforementioned in-line check valve in this post. Assume there is a check valve for the Aux tank too? Right now, my Aux pump doesnt run very much, rarely. My final test is to be in a place long enough with the auto level on, so the DOT tanks eventually deflate below 60PSI and isolate. I know aux. pump may run if I inflate/deflate bladders to move a slide, or eventually, if we use the pneumatic doors. I "assume" that below 60PSI in the DOT tanks, the aux. pump will supply air if the auto-level needs to inflate a bag?
The short answer Yes.
Mike
Getting ready to install kit in my six packs and replace the check valves as well, since I am under there! I found this online from Van Horn Truck, Haldex KN23000 check valve for $10.99 ea. This is a brass check valve and at a really good price. Hope this helps some out there! 1/2 male, 1/2 female.
I replaced the bad check valve that is in the line from the compressor to the AA air tank. After I replaced the check valve I ran the HWH compressor, it took little over 6 minutes to cut off. After it shut off I turned the power off to the compressor. Today I go out and check the pressure valve on the bath door and it read zero. I then went and ran the compressor again and this time it only took 3 minutes to shut off. I figured that was because the AA tank did not have any or a small leak and the compressor did not have to fill that tank from empty. I then started hunting down the leak and I found it in a fitting feeding the bed air door.
While I was looking for the part number of the fitting I was needing I looked at the air semantics. I did find the on the drawing that Michelle informed us about above.
I have come to three conclusions.
1. Coaches with Active Air have two air tanks. One is for the air bags and the other is for the slide bladders, step cover, and both pocket doors in the bedroom. The pressure switch on the HWH air compressor only is reading the pressure in the bladder tank. If the AA tank runs down and the check valve works, the pressure switch will not see it. That is why when you try to level the coach with the engine off, the compressor will run since the pressure switch has no idea how much air is in the AA tank.
2. I have read multi time about comments about the blow off solenoid is leaking, or the bowl for the filter is bad/leaking. I think the only way you should be able to figure those out is while the compressor is running. With the check valve between the filter and the pressure switch once the compressor shuts off there should be no pressure in the filter bowl, that is unless the check valve between the filter and pressure switch is bad and leaking.
3. Michelle needs to apply for a job as tech support for Foretravel.
Thanks Michelle for answering there question's and posting the updated configuration performed in 2003, My coach still has the original configuration as in the before picture and I will perform the update. I like the double check valve set up. This is the first time I've had a chance to check on my last post.
This is a great info thread.
When I took ownership of my IH45 back in April it had a number of air leaks and the compressor would run every 10-15 minutes for a bout 90 seconds. After chasing many I had the coach in MOT for other service in June. While there I had them chase some of the air leaks down too. They found a few more plus the pressure switch had issues.
After I left in June my compressor probably ran once or twice every couple of hours at most. Now into August and camped/stationary for the last month, I notice it running more frequently again, like every 30-40 min or so. Chasing leaks I didnt find any in the main bay when the compressor had shut off but I did notice the solenoid under the plastic bowl felt loose. I could actually move it up and down which didnt see right. In addition I noticed every day the bowl seemed to be collecting a lot more moisture then previous times.
I took it all apart, tried to reseat/reseal the fittings at bottom where the solenoid connect and reassembled. For about a day it seemed to help a lot with much less running. Then I notice an odd behavior...over night in the very early hours of the morning the compressor would run every 10 min for 40 seconds. I pulled the fuse and left for half a day. Rechecked all the fitting work on around the solenoid (never was able to really see an air leak with soap water/kids bubbles). When reinstalled the fuse strangely the compressor went back to a once an hour 40 second run for rest of the day.
Again over night it went to the 10 min cycling behavior. Pulled fuse/left it off half a day/re-installed and back to the once an hour running.
Reading this whole thread multiple times and looking at my suspect parts, I went ahead an ordered new bowl, solenoid assembly, and the check valve for good measure.
Anyone ever see that behavior with cycling and then it would go away after a period of being off/disconnected? I was wondering if possibly the solenoid may have had something to do with it under the bowl and all the extra moisture I am seeing the trap/bowl.
Thanks
A couple of questions -
how much is the temperature dropping from daytime to overnight?
How humid is it where you are?
Does the IH have a desiccant bowl as well or just the condensate bowl?
When the compressor kicks on at the 10 minute cycling behavior, do you see any out-of-level indicator lights on the control pad?
Have you checked the air tank drains for signs of moisture?
At a 10 minute interval, that doesn't sound like the coach waking up to relevel (that's usually every 30 minutes), but rather something dropping below a lower air pressure limit, possibly due to cooling temperature contraction of the air or moisture somewhere in the system.
temp on south texas has been mostly 100-108 during the days...although we have been just 97-99 last two and dropping to mid 70s at night. Humidity is lower today than it has been ...around 30% and it is going above 50% at night so perhaps that would account for more of the moisture.
Just a condensation bowl unless I am missing something.
Havent checked the other drains yet. Will do that next.
I havent checked the leveling/control panel but will. Honestly we dont notice the coach level changing at all. I did run the coach after sitting here +2 weeks just to air tanks and see if any diff with 12v compressor. The air levels after 2 weeks in the tanks (A/B) on Silverleaf were single digits. So I know there is a slow leak somewhere in level/bladders likely.
The loose connection for the solenoid at the bottom of the bowl still bothers me. I can physically wiggle it and move it up and down which doesnt seem right.
That solenoid is NO (normally open). I agree it shouldn't move - the fitting into the bowl should have an o-ring and a C-clip - but if that were a significant issue, the aux compressor wouldn't be able to build pressure and would just keep running. The solenoid on the bowl only closes when the aux compressor is running. Once it achieves desired system pressure or level, the compressor shuts off and the solenoid opens to relieve the compressor and blow out the condensate. That's the psssshhhhhewww air release you hear when the compressor shuts off.
(I don't think there's a timer on the aux compressor - there isn't in the older coaches. That said, I'm not sure if there's a thermal protection device on the aux compressor - if there is, maybe things are getting hot and tripping something?)
Good info. I dont believe there is a "timer" per-say but when I was at MOT last and working through air leaks tech did say the pressure switch had a problem and needed to be adjusted as I recall. It almost always only runs 40 sec now. Perhaps a bit longer when I have had it unplugged for a day or so but then right back to 40 sec on/off/release.
I dont think its overheating or tripping. At this point seems like a minor leak or so that drives the 60-90 min run, and then humidity levels going +75% overnight from under 40% during the day that maybe causing the added runs/restarts every 10-15 min. Sometimes as I recall when it gets in that mode the runs are shorter than 40 seconds too but still over 20 sec
Parts should be here next day or so for bowl/solenoid and check valve. Going to replace those and see where I stand next.
Thanks again for response. Very helpful
Keep posting the symptoms/observations - the collective will get to the bottom of this. It could be as simple as a new pressure switch.