Air Supply for Accessories

paddywagon · 05-05-2021, 07:52 PM

Hi all,

I am in the process of relocating one of my air tanks to make room for a water tank. I am almost wrapped up but I would like to add in plumbing for my new oh-so-wonderful air seat and an air horn. Which of the two tanks should supply these accessories?

I also understand that I will need a protection valve between the tank and accessories. Can someone point me towards a part number or such for one of these valves?

Thanks!

Simplicity · 05-05-2021, 08:11 PM

Generally, there are three tanks, either separate or combined into one with walls separating them.

The Primary tank is for your rear brakes, since this is where the majority of your breaking power comes from.

The Secondary is for you front breaks.

The third is your reserve/emergency tank.

I've never looked to see where my seat is connected, but I'm "guessing" it's the reserve? I say this because I don't think they want to routinely take air from the brake tanks.

If no one gives a more solid answer, let me know and I'll go trace mine.

Per the plumbing part of it, I don't know, but I'm interested because I have an air horn I want to add too.

rossvtaylor · 05-05-2021, 08:14 PM

Hi PW. First a question...do you have airbag suspension in your bus, or springs only? If you have airbags, you'll already have a protected tank. If not, you can add a tank and one of these valves between the air brake system and the aux tank you add.

https://www.amazon.com/World-America...0263569&sr=8-3

I usually get mine from anythingtruck.com but for some reason their site wasn't loading for me. The have a bunch of them. Search "pressure protection valve" to find those.

EDIT after reading your post again: If you only have two tanks, that's probably rear and front brakes (primary and secondary systems). You would tap into the line feeding one of those, using DOT approved fittings and line, then add a Pressure Protection Valve which feeds the aux tank you'll add. From the aux tank, you can put in lines for your seat and your horn and you should add one with a quick connect for air tools or tire inflation.

With this, the system pressure will build to about 60 psi (depending upon the valve you select) then will fill the aux tank too. If you lose pressure in the aux tank or a line off that, your brake system won't drop below 60 psi.

rossvtaylor · 05-05-2021, 08:20 PM

Steve makes a good point about the single split tank. So, the key to know if you have an aux tank now would be if you have airbags or any non-brake air systems.

paddywagon · 05-06-2021, 10:43 AM

Great info. Thanks!

My bus does not have any auxiliary air systems (suspension, etc.), just air for the brakes. However, one of my two tanks definitely has multiple chambers in it. I'll document how all the plumbing is routed and try to figure out what's what.

I'll drop by NAPA today and pick up a pressure protection valve. Is there a particular pressure setting that I should look for? I saw ones online between 60psi and 90psi. To do this right, I have the feeling that I know the answer to this question: is it necessary to add an auxiliary tank, even if it was just for, say, the seat?

Simplicity · 05-06-2021, 01:05 PM

Quote:

Originally Posted by paddywagon

Great info. Thanks!

My bus does not have any auxiliary air systems (suspension, etc.), just air for the brakes. However, one of my two tanks definitely has multiple chambers in it. I'll document how all the plumbing is routed and try to figure out what's what.

I'll drop by NAPA today and pick up a pressure protection valve. Is there a particular pressure setting that I should look for? I saw ones online between 60psi and 90psi. To do this right, I have the feeling that I know the answer to this question: is it necessary to add an auxiliary tank, even if it was just for, say, the seat?

I searched google and this is what it said:

Pressure protection valves are used to isolate auxiliary air systems from the brake system. This is done to preserve air for braking in the event that the auxiliary system develops a major leak.

I'd say this would be a "yes" to if you should add an auxiliary tank. But, you may already have one. The pictures of your tank(s) will help.

s2mikon · 05-06-2021, 01:47 PM

I would get it for 90# That will leave more air for brakes. The horn needs 90+ to scare dumb drivers and if you spend to much time in the seat you may need 90+ to hold you up

And the tank will make the horn work better too. You need the tank.

rossvtaylor · 05-06-2021, 02:18 PM

As Steve said...yes, you need another tank. It doesn't have to be big, but you should have one which gets filled from the primary system. 60 psi is pretty standard, and will still leave you with brakes until you get down to 30 psi or so...when your spring brakes will come on, whether you want them to or not...but there's no problem going with the 90 as s@mikon said. Either way, your aux will fill up to 120 psi and when your engine's running you should never run out of horn or seat air.

aswallie · 05-11-2021, 01:10 PM

I'm a bit late to the party but I might be able to offer an additional suggestion to the mix, I suggest an air manifold. My bluebird all american has air everything and this is how they have the accessories set up. The main feeds the manifold and from that each line gets primary pressure as well as the reserve tank. I recently plumed in a shut off between the main and the manifold and an aux compressor into the reserve tank so I'll have accessory air while the engine is off. I have the exact same valve as linked above from Napa and I plan on putting that in partake m parallel with my shutoff so my accessories still get air while the engine is on, which that currently do not.

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