Using 2 12V air compressors with 1 tank

[JWMcCrary]

Curious if it will work without causing any issues for the ARB compressor. I have run this compressor since 2007 without fail, works great just slow filling tires. I added a 2 gallon tank to it couple years ago which helps for the first tire, after that it's about the same as it was. I was thinking of adding 100% duty cycle Viair to the tank, which would have both compressors connected, meaning the Viair would be pushing against the ARB compressor. Will that hurt anything at 150 psi? I have a shut off valve on the line between the ARB and the tank that I close when wheeling since it doesn't need the tank and no need in trying to keep it full. I have looked all over my ARB for a model number but can't find one, plan was to call ARB and ask if it could handle 150 psi. The only thing I remember from the instructions were to not run it continuously for more than 45 minutes. I drive it a lot more now than I used to, would be nice to air up faster, and also not have to worry about isolating one compressor from the other.

 

[JAFO]

I'm no expert, but I stayed in a Holiday Inn Express once.
I piped two 220Volt shop compressors into the same line. I run one, or the other, or both, depending on my load (sandblasting, etc). Never have had an issue with them both running at the same time. They both have their own control valve. One is a 30 gallon tank, the other a 60 gallon. Lots of capacity.

 

[SHX669]

I would think you'd need a " check valve "and or relief in there somewhere . Not good trying to start a compressor "against head pressure"

 

[Apogee]

I was plumbing up an ARB this past weekend and IIRC, it called for a minimum of 85 PSI and maximum of 105 PSI air supply, so that would mean that you'd need to add a regulator between your tank and ARB solenoid valve if you intend to run your reservoir tank at 150 PSI.

 

[Digger556]

Leave the ARB on its own shutoff switch, that way it will turn off at 100-105psi. Put a check valve between the ARB and the tank.

Now the ARB will assist up to its max pressure, at which point it will shut off and the VIAIR will have to finish the last 50psi on its own. The check valve will isolate the ARB from the higher tank pressure until it drops below 100psi.

If the VIAIR doesn't let the tank drop below 100psi, than the ARB won't cycle, but I have a feeling that if you are filling tires, the VIAIR won't keep up and tank pressure will drop considerably.

 

[gnpenning]

What's the black ABS pipe for?

Dry storage for documents???

 

[JWMcCrary]

What's the black ABS pipe for?

Catch can for Coldduck. At hwy speed it pushes gear oil out. I made this to catch it so it drain back in.

 

[lonesouth]

I would run a check valve right after the ARB to protect the ARB from the pressures the viar can generate, and then another check valve right after the air tank to prevent the ARB from filling it. This would keep pressure only in the line from the ARB, reducing volume the ARB will fill, and allow the viar to have the tank for when you need the volume. Reduces the need to manually open or close a valve.

if you want to go further to protect the ARB from overrunning the duty cycle, add in a relay and switch so that only one pump can be powered at a time.

 

[ntsqd]

How about just letting the viar handle the airing-up chores and leave the ARB to running the diff? The older ARB compressors weren't good for a lot of CFM anyway, doubt that you'd notice much or any difference.

 

[Steve83]

I agree with ntsqd - running compressors with different cutoff pressures is like running a 6V alternator parallel to a 12V. It could be done, but it wouldn't pay off.

If you get several cheapo compressors with the same max PSI, you can run a bank of 1, 2, or 20 into 1 system. That's how I built the OBA on my '83, but I'm only running 1 compressor so far. It's wired & plumbed for 4.

 

[ntsqd]

Alternately remove the ARB compressor entirely and add a regulator to an outlet from the tank to step down the pressure for the locker system.

This is how I plan to plumb the 4rnnr. Puma compressor and tank, with a regulator to control the locker system pressure within spec. Have all of the pieces, just need to figure out the mount brackets. And this is how I plan to plumb the Bronc-up's ARB's. The 4rnnr is the prototype, what I learn from it I'll apply to the Bronc-up.

 

[JWMcCrary]

Leave the ARB on its own shutoff switch, that way it will turn off at 100-105psi. Put a check valve between the ARB and the tank.

Now the ARB will assist up to its max pressure, at which point it will shut off and the VIAIR will have to finish the last 50psi on its own. The check valve will isolate the ARB from the higher tank pressure until it drops below 100psi.

If the VIAIR doesn't let the tank drop below 100psi, than the ARB won't cycle, but I have a feeling that if you are filling tires, the VIAIR won't keep up and tank pressure will drop considerably.

This is what I'm going to do and the simplest. Will update on how it works out.

 

[ntsqd]

I don't think that is the simplest as I think leaving the systems separate would be the simplest, but I am curious to hear how it works out.

 

[JWMcCrary]

I don't think that is the simplest as I think leaving the systems separate would be the simplest, but I am curious to hear how it works out.

It's the simplest to accomplish what I am wanting to do. To hook them up separately I would not have posted asking for opinions.
Right now the ARB has a hose disconnect on a T that is inline with a shutoff valve going to the tank mounted where the aux fuel tank used to be. The way it is now, before I change anything, I can air tires using just the ARB or with the tank depending on whether or not the valve is open. Based on what Digger556 suggested I can put a check valve between the ARB and the T, and then plumb the Viair directly into the tank. Both compressors should be able to assist without any damage to the ARB, provided the check valve does it's job. I have 450C Viair compressor, bought a check valve this morning, just a matter of when I get a chance to work on it.

 

[gddyap]

Use unloading check valves between each pump and the tank. They'll pump up the tank and when they shut off, the valves relieve the head pressure. The pumps aren't fighting the pressure in the tank when they start up again. Easier on the pumps.

 

[JWMcCrary]

UPDATE: Was definitely worth the effort to hook up. Starting with full pressure it will drop enough for the ARB to kick in but within a few seconds from that point a tire is up, cut the time to fill a 37 from 6 up to 22 by well over half. Didn't time it but couldn't be more than a minute between tires for the pressure to be back up and both compressors off.

I already had the tank connected to the ARB, only thing I did there was add a check valve between the compressor and the air hose quick connect. I plumbed the new Viair staright to a previously plugged off port on the tank. The viair is capable of 150 psi but right have a 120 psi shutoff regulator on it that I already had on hand.