Ford Powerstroke Diesel Forum banner

on-board air

4K views 10 replies 8 participants last post by  07OUTLAW 
#1 ·
I've been reading up on all the posts about on-board air and air horns. I'm getting ready to order mine, probably a 2.5 gal tank with the VIAIR 350C, but a question first. The electrical diagram VIAIR has shows the pressure switch driving a 40 amp relay for the air pump. If the pressure switch can handle 30 amps (The way I read the spec anyway) and the pump only draws 17 and the upfitter switch is fused for 30 amps (aux 1), Why do I need the relay?

BTW, my usage will be primarily for tires and air wrenches to change any flats I get on the road, with an occasional use of the air horn. I plan to mount the air horn behind the license plate and the tank and compressor on the passenger frame rail.
 
#2 ·
I have the exact same setup as your thinking and I'm not positive as to why, but I mounted it to my up fitter switch w/ 30 amps...

Convenience more likely!

What size tires do you plan to air up? A 350c is only capable of up to 33" tires... Or it will take a LONG time to get anything done. Plus a 350c is only a 33% duty cycle compared to a 450c which is 100% duty cycle... I found that out after I bought the 350:doh:

But I will say that for air horns a 350c w/ a 2.5 gl tank is PLENTY :evillol:

 
#4 ·
It has absolutely Nothing to do with voltage drop. A pressure switch is considered a control device and usually not rated for high current values....and by high current, I'm talking about the 17 amps that the compressor draws. Something else that has to be considered in this equation is the fact that when a motor starts, there is an inrush of current that is usually several times higher than the full load current......something that the pressure switch definitely cannot take over a period of time........thus the relay. A relay like the one pictured in the Viair electrical drawing, has a purpose....to take a small amount of current from the pressure switch and operate a coil, which in turn closes a set of contacts that are heavy enough to operate the compressor motor. Hope that clears it up for ya.
 
#9 ·
Tool box mounted air system for horns and tire inflating

can I have some opinions on mounting compressor and tank in bak box tool box under back flip tonneau cover. For those not familiar with bak box its suspended from tonneau cover rail and doesn't sit on bed floor. I think it would be good mounted in toolbox but don't want to lose bed space of floor mounted box. Not quite sure if bak box its steady enough.I haven't actually seen one in person.Any help would be appreciated.
 
#10 ·
i have a 350c on my truck for airing my tires up between the trail and the street. it takes way too long to go from 15 to 25 psi.

it won't power air tools very well either

and the pressure switch my compressor came with was an inline 200psi switch which isn't designed to the the on/off switch for the compressor.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top