Got some questions about onboard air

[Suza]

The idea I have is to mount my 12v compressor either under the bonnet or in the rear quarter panel and then and then have a line running to an air tank mounted underneath next to the chassis rail and the have a t coming off the tank with a line going to the back and another to the front.
I am thinking of using a pressure switch I have from an old 240v compressor, which brings me to a question will a 240v pressure switch still work at 12v

Cheers for your help

[nzlux]

It will work just fine. Inside the switch is a spring loaded contact. When the pressure drops the contact closes and the power flows. The switch is built to handle many more amps than you need.

[snotgoblin]

Sure will. That is exactly the set up on my truck, except using the air con compressor...

I did not set it up, so cannot be too much more help.

[hamboy]

http://www.offroadexpress.co.nz/Forums/viewtopic.php?f=18&t=34450&start=15 Toward the bottom. Onboard air easy peasy lol

[kbjj]

Suza, lots of others have used these pressure switches to do just that job, so could be ok. But... just be aware that, for example, a 230v ac 5amp contact is not rated at 5amps dc.
DC contacts usually have a larger contact gap when open and a stronger 'snap' action. AC self distinguishes any arc drawn (better than dc) as the contacts open due to voltage being at zero twice every cycle (Hz). Not the case with dc.
If in doubt, use pressure switch to switch a relay with correct rating for compressor. Some compressors draw alot of current.
Hope this helps
Jeremy

[petefj40]

I just use this small adjustable pressure switch. (the grey box at the top of the picture) Brought it locally for stuff all.

[rano99]

The idea I have is to mount my 12v compressor either under the bonnet or in the rear quarter panel and then and then have a line running to an air tank mounted underneath next to the chassis rail and the have a t coming off the tank with a line going to the back and another to the front.


Cheers for your help

use large diameter hose or you'll end up with good pressure but restricted flow

[Mattman]

I put together a manifold which has an unloader valve on it, then a number of ports for my fittings such as pressure gauge, safety valve, pressure switch, quick connect coupling etc.

You can get away with a lot less but it's handy to have it all setup permanently like this. Cost was about $100 I think for all the bits and pieces.

I used a high temp hose off the compressor as it gets very hot under load and the plastic hose can slip.