Add Dump Valve for Air Suspension

[fo4imtippin]

Hello all,


I believe i have a slight leak in my Height Control Valve. Currently the one on there is not dump eligible. I haven't pulled it off yet, but it looks a lot like this one.
https://daytonairsuspension.com/products/leveling-or-height-control-valve-vs227


When i do replace it, i would like the ability to dump the air out of the bags to help level my bus a little if needed. What do i need to do to change over to a valve that lets me do that? I would be okay if there is a button on the dash to control an air solenoid or some sort of ball valve outside that i can activate the dump.



My Parts Diagram



It looks like my part diagrams have the same one with "dump" feature looking like it has 2 more ports. I do have a tank just for the air suspension but not sure if it has its own check valves or PPV on it yet.



https://www.stengelbros.net/334-1716-Replaced-by-334-1648A_p_9881.html

 

[fo4imtippin]

I think im answering my own question, but will still gladly take tips.
After reading the manual, looks like i could just add a Tee to the line going from the tank to the valve and then insert a 12v pneumatic solenoid before going to the dump port. I was thinking that i would do normally open so that if a fuse blew or something my bus would be less likely to kneel while driving.



It looks like a lot of kneeling buses route the parking brake air supply to this port to make them kneel when the parking brakes are applied.


https://www.hendrickson-intl.com/ge...y-Height-Control-Valve-Installation_Rev-G.pdf


Im also thinking of adding an air gauge after the height control valve as i want to know what my weight distribution is at a given time.

 

[Booyah45828]

Dump valve goes between hcv and bags.

https://www.overdriveonline.com/business/article/14873884/how-to-install-driver-operated-dump-valve

Here's a quick how-to guide with a little parts guide. You can install a manual 3 way valve instead of an electric one. I like the manual ones because you can leave them either inflated or dumped. Electric ones are typically NO or NC like you allude to, requiring power to do the opposite.

https://semitrailers.net/shop/manually-operated-air-bag-control-valve-sealco-17610/

 

[s2mikon]

I did mine a few year ago and used air switches to control dump valves. If you want I will look in my book and find the part numbers. It is nice to have air dump.

 

[cadillackid]

if you just put a solenoid valve on a Tee between the springs and HCV, wouldnt you end up dumping the whole air system down to the protection pressure?

 

[s2mikon]

Chris, you are correct. That is why you use a air system dump valve. It closes one port and opens another port, the exhaust. These are air operated. I'm going out to my bus and look at my book and get the part numbers and share them.

 

[cadillackid]

ahh! that makes sense! similar to a park brake dump valve.. then you could either have a manual valve in the cab for the relay circuit or a solenoid and switch that would control the air to the relay..

 

[s2mikon]

Here are the the part numbers I used: Control switch: Velvac 032228, Dump valve: Velvac 032195. I did this front and rear. I have 4 switches and 4 dump valves. If I park along the curb I can dump the left side and it sits close to level. If I use a fueling station with only 1 hose I lower the opposite side and it fills faster due to the shape of the tank. I dump the front to assist DW to get in and out. It also makes it easier to adjust leveling blocks too. It was less than 200 dollars when I did it. Now it is probably 500 dollars now due to inflation.

 

[#1FordFan]

I did this with (3) 1/4 inch valves.
I eliminated the height valve.
One valve to isolate the rear bags from tanks
One to feed the bags and set height
One valve to dump air from bags.