| Author | Message | ||
| LOU MURDICA (Loucon)
Rating: N/A |
No caps now I’m hooking up a small 12 volt air compressor that they use on lifted pickups. I’m have an air leveling system on my mc-9 and when it’s parked for more than a week the air leaks out of my rear bags. The though I have is that I can pump the back up without starting the motor all the time. I plan to put a ball valve between the pump and the system so I don’t get feed back while driving. Can you see anything wrong with doing this? | ||
| Geoff (Geoff)
Rating: N/A |
No. You might burn out the 12v pump, though. | ||
| LOU MURDICA (Loucon)
Rating: N/A |
Why do you think that I will burn out the pump? All it will do is pump the system up, then it won't be used for aleast a week. These pump run all day on these lifted trucks with air bag systems. | ||
| Marc Bourget Rating: N/A |
Typically, only needing one "pump up" a week is a system that's in pretty good shape. Usually you see owners going to accessory pumps when the leak down is a matter of hours. Easier to install an energy wasting system than do proper preventative maintenence. Although, I must admit, my father's age related hearing loss prevented him from hearing a rather loud leak in his Prevost. Once it was pointed out to him, he fixed it promptly. He just couldn't hear the leak. There's a difference from the 12V units used for emergency flat tires and the OEM caliber pumps used on the delivery trucks that maintain driveshaft angle via air bag systems. Geoff was probably being a bit conservative in view of those among us who wouldn't notice the distinction between pump construction and leak rates. | ||
| Geoff (Geoff)
Rating: N/A |
The pumps used with auxillary air bag systems do not run all day, they are used to occassionally add air to the air bags, which do not require much volume, or additional air for that matter unless the system leaks. If you hook it up to the bus air system it will have to air up the either entire system or just the accessory air tank (depending on how your system is hooked up). My comment that you *might* burn out the 12v pump was based on knowledge of the limited system that pump was designed for. A better and cheaper pump would be a small 120v air compressor, it might be noisier but would run less. --Geoff '82 RTS AZ | ||
| Chuck Newman (Chuck_newman)
Rating: N/A |
I will be keeping the air up for leveling, door operation, fast getaway, etc. all the time. I was looking at 24vdc compressors to do so. Not cheap either. I am leaning toward DC as some have told me they have had problems with inverters withstanding the start load of even small 120vac compressors. And we will be boon docking much of the time. My question is are we saying a DC compressor is inherently liable to fail more often than a small 120vac compressor? Thanks. | ||
| Geoff (Geoff)
Rating: N/A |
There are good inverters, and there are other inverters. I recently heard a story from a fellow bus nut that was having problems with his 120v refrigerator not working-- he finally figured out his inverter could not handle the start up load. Sound familiar? I have a Trace SW2512MC and it has no problems starting anything, including a 15,000 BTU air conditioner. I have a little 1.5HP, single tank 120v air compressor for my bus. However, it is a toss-up as to which makes more noise, the air compressor or the bus engine! Shop wisely and test for noise before purchase... --Geoff | ||
| Chuck Newman (Chuck_newman)
Rating: N/A |
Geoff, Thanks for the input. For me noise won't be much of an issue as I will have the compressor inside a pressure ventalated sound box, so it won't be an attention grabber at parks or anywhere else. What is your recommendation: If I plumb into the aux tank via a check valve, is the small tank combo units still necessary? Or can I get by with just the compressor? I'm trying to keep the sound box as small as possible. Thanks. | ||
| Arnold J Molloy (Ayjay)
Rating: N/A |
Hi: I have a 120 PSI, 120VAC "Grainger" compressor w/check valve plumbed into my air compressor line, It's located in the compartment with my generator. It was initially installed to obtain a short (quiet) startup (feeds the suspension, brakes, etc.) while in a campground to allow me to get an early start without waking up half the camp airing up, with the 8V71. I've T'eed off an air chuck for tires a/o any other air needs. If boondocking my Zantrex 2524 handles all the AC needed. AyJay | ||
| John MC9 Rating: N/A |
From everything I've ever read, air leaks in a bus are usually attributed to leaky wipers, leaky leveling valves, leaky air beams, and leaky air bags. Maybe leaky air accelerator assemblies, included... Why not spend the time (it equals cash anyway), and track down the leaks, and fix 'em? I drove MC9's part-time for Bonanza Bus (Massachusetts) years back. I'd start my run by just starting the engine at the barn, doing a walk-around, and rolling off in a minute or two. It doesn't have to leak. | ||
| FAST FRED Rating: N/A |
To save the pump , you might consider using an Hour Meter to keep track of the duty cycle. Also use a fuse that is REAL close to the pumps needs. IF it overheats , hopefully it will pop the fuse. FAST FRED | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
I was planning on putting a little quiet 110v air compressor that I have here on the system. I bought it so my ex-girlfriend could airbrush. It's pretty much worthless for anything else. It has no advertised horsepower, and it's on a 3 gallon tank. If I put it inside the body somewhere, you wouldn't even notice that it was there. I'll save the 5hp compressor for better things.  | ||
| BillNJ Rating: N/A |
I just searched Google and most airbrush compressors are 28 to 40 psi. One that went as high as 120 psi was $600. You probable need more than 28 to 40 psi | ||
| JW Smythe (Jwsmythe)
Rating: |
The one I have is a 100psi compressor. I bought it with the idea that I could possibly run some of my air tools on it, and it was small enough to throw in the trunk of my car, rather than my 20 gallon compressor that takes up the whole back seat. Needless to say, my tools work for a very short time, and then I have to wait for it to fill up again. Ok, I dragged it in from the garage. The label says: "Husky" brand 3 gallons 0.7 SCFM @90PSI 120Volt 100 Max PSI The label on the bottom says: FP204700 120V, 50Hz, 2.2A 3 gallon tank Maximum Rated 100PSI Bar Code: FP2047 0 45564 60725 8 It has a regulator built in, so she could have turned it down to the pressure she needed, assuming she had ever bought an air brush. She never bothered to buy an airbrush, so she never got to airbrush with it. I dug around a little more. Aparently it has a 2hp motor on it. It doesn't say that anywhere on the labels. The important parts are, it's small, light, gets over 80psi, and it's here. I wouldn't go out and buy it to stick in the bus. Since it's here, just taking up garage space, it seems ideal. | ||
| BillNJ Rating: N/A |
Looks like you have a winner. | ||
| pipes Rating: N/A |
JW is this correct..........""120V,> 50Hz, 2.2A"" | ||
| Jack Conrad (Jackconrad)
Rating: N/A |
.7 SCFM @ 90 PSI is very low volume. Using air tools will require many breaks for the compressor to catch up. Check the required SCFM on some of your air powered tools. Hope this helps, Jack. | ||
| Pete/RTS Daytona (Pete_rtsdaytona)
Rating: N/A |
Hmmmm .7cu ft / minute I'm guessing - average bus air tank 15" round x 24" long -> cu ft = r"/12 x r"/12 x length"/12 x pie -> 7.5/12 x 7.5/12 x 24/12 x 3.14 = approx 2.5 cu ft 90 psi equals approx 6 athmos (6 times as much air volumme at 90 psi than at normal athmoshere aka = 90 psi = approx 6 bar 2.5 cuft at 6 bar = 2.5 x 6 = 15cu ft at 90psi your pump .7 scfm would require about 21 minutes PER TANK to fill to 90 (PER TANK) This is a rough approximation doubt if that pump was design for 100% duty cycle for 21 mins per tank Pete RTS/Daytona You can take the instructor out of the classroom but you can't take the classroom out of the instructor - IBM Instructor/Engineer/Programmer 30 years | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Pete, I was just going to put it in to maintain pressure, not really to fill it up from empty. The way I'm looking at this one is that either I'll sell it at a yardsale for $10, or run it in the bus for a while and maybe in a year or so it'll eventually fail. I agree with the duty cycle. I bought a 5hp 20 gallon compressor at Home Depot to work on my bus in March. I bought it at a Home Depot on Dale Mabry in Carrolwood (Tampa). It was on the way, to Brooksville from where the bus is. The box was open, but the boxes are heavy and easy to rip the flaps open just moving them around, so I assumed it had been opened moving it. I got it out to my bus, plugged it in, saw it was building up pressure, so we threw the box away. The only failures I'd seen from them were the compressor failing to build up pressure. Sure, it would build up pressure, but at 100psi the switch that would shut it off at 120psi started leaking. It could only ever get 100psi, so it would keep running forever. We ran it for about 2 hours like that, and it started smelling VERY hot. I guess there was no thermal shutdown on it, or that was broken too. I ran it hard, shutting it off every hour to let it cool down. When we were done working for the weekend, I brought it back to Home Depot, and traded it for a new one. This time, I made sure the box was sealed before I started moving it. The first two boxes on the floor were open, so I kept digging for a sealed one. | ||
| David Hartley (Drdave)
Rating: N/A |
3 to 5 cu.ft/min is more on what it takes to overcome losses from leaks, valves, windshield wiper motors, skinner valves, hoses, air seat leaks and general stuff. You would be astounded if you ever found out where all that air goes.. If anyone claims "no leaks" I say " Liar Liar !!! Keep the air pressure down to 100 psi or less to keep the air compressor governor from going into dump mode... | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
JW Smythe, our coach actually lifts up its front end right at 91 psi indicated, so we looked for one that would go at least 100 psi. We found an IR unit that was tankless and swtchless that had a variable pressure regulator on it. It was rated 1/2 hp, which can produce something like 2 cfm at 90 psi. With this plumbed in to our main tank, it will pump up the coach in about 10 minutes and it is no trouble to run it on the inverter. We got it for around $65 plus shipping from eBay, and it looks new. It's just about the best balance between current draw and speed that we could find. We don't need it often, but we're glad we have it. I noticed that you mentioned a 5 hp compressor that you bought from Home Depot to work on the bus. If that unit plugs into 120 AC, I believe that you will find that there is not supposed to be any more than 2 hp availble from the plug in an ordinary outlet. Two hp should be able to give you about 8 cfm at 90 psi. If you check the ratings, I expect that you will find that the truth was stetched a bit. Good luck on your setup. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Tom, Ya, I know advertised specs rarely match real world specs, but I don't have more more to work with. I know that in the house I'm in now, I can run my 3hp 15gal compressor for about 10 minutes before it pops the breaker. I have no clue how much other stuff is on the circuit. Things in various rooms go off when it pops, and since I need the compressor when it happens, I go out and flip the breaker. I hate this house. Nothings marked, and there's no rhyme or reason to the power circuits. | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
JW, it sounds like time for a new database! Good luck. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska |
