Looking @ schematic, I see a "wet tank". cannot find on my coach.
Also both my tanks are under front of the coach.
What is the "wet tank" use for?
Chasing why my HWH compressor will not come on, even at less than 35PSI in system.
Bill Chaplin
Billchaplin@sbcglobal.net
"Wet tank" is a tank where hydraulic fluid is stored before it is pumped out into what ever that hydraulic fluid is operating. I am thinking that it is storage for your hwh leveling system. But not 100% sure, considering that I can not see the schematics.
On my 96 U270 the air system has 3 tanks. Air from the compressor on the engine first goes through the dryer and then to a tank in the rear wheel area. There is a drain for this tank just in front of the left rear wheel. This tank is called the wet tank as any moisture left in the air would tend to condense in this tank. It should be drained fairly frequently as recommended by Foretravel in the operators manual. If a lot of moisture/water is present the dryer needs servicing. The air then goes to 2 tanks in the front wheel area used to supply air for the brakes. The location of these tanks may be different on other models.
Jerry Whiteaker
96 U270 36'
Hi Bill,
On our 1997 U 320 I have one wet tank in front of the driver's side rear wheel/tire. Then there are two wet tanks just in front of the front axle. The fronts are a pain to check. I have never noticed any moisture release from any of the three tanks. I would assume the air dryer is doing it's job.
You can run the air lines from the front tanks over to the front wheel well just like the rear to make it easier to check.
Learn something every day. Never heard of a particular air tank in the system being called a wet tank. We drained all of them of moisture.
STOPPING WITH AIR BRAKESDry air flows to the supply tank from the dryer outlet.
Typically there are 3 air tanks or reservoirs.
Supply Air – Primary and Secondary air supply
The air is stored in reservoirs until brakes air is applied.
The supply tank (Wet Tank) is first tank in system and moisture tends to collect in it more than others. Supply tank has pressure relief valve if system becomes over pressurized.
The Relief valve vents excess air to prevent and damage to system.
The Supply tank includes a low pressure indicator which monitors over all system pressure.
If pressure falls below 60 PSI – an alarm will sound and light will come on to notify the driver of a low pressure condition.
Air from the supply tank flows to the primary and secondary tanks. These tanks are protected by check valves to prevent the total loss of air in the event of a failure between the service tank and compressor.
Tank and Compressor.One of the tanks will have a pressure control valve that allows some backflow of air in the event of a failure between the services for the dryer purge cycle.
The tanks have a manual drain valve at the lowest point that expels water that accumulates over time. Some tanks have an automatic drain valve for convenience.
Overview of how Air Brakes Work [ForeForums Foretravel Motorcoach Wiki] (https://wiki.foreforums.com/doku.php?id=technical:brakes:howtheywork)
Just have never heard it refered to as a wet tank, but then the company I worked for only had air ride tractors for a couple years before I retired. And to add confusion to the subject, on a tractor that pulls a dump trailer there is a large hydraulic storage tank behind the cab. It is often refered to as a "wet kit", with the tank being a "wet tank". One has to hook up the "wet line" when he hooks up his trailer. It stores the hydraulic fluid necessary to lift the box on the trailer frame. There use to be lots of coal trucks around here. Guess it is probably local names that get coined to keep thing simple.
Image below shows the tank called "Wet Tank"
My '91 Grand Villa on an Oshkosh chaissis (V917) only has two air tanks, not three, both of them mounted in front of the front axle. I always drain both and never have had a moisture in ether. I do not have a schematic, just a chassis drawing so I do not know if ether of them is considered to be a wet tank.
Thanks to all who responded to my post
Thank You Thank you thank you.
Found drain valve for 'wet tank', (we called that an air/oil seperator on aircraft. )
Drained for 1st time in over 18 months. Losts of water, very little oil.
It is now on my preflight check list !!
Bill,
If you found lots of water in your wet tank, it's time to replace the filters in the Haldex drier. How long has it been since they were changed?
Bill,
If "lots of water" came out of the wet tank, your air drier filter is probably toast. Normally, little if any water should come out. You might want to check to see if your air drier has the replaceable cartridge (dessicant) or whether you have to rebuild the air drier. You first have to determine which model of drier you have, then go online and look at the instruction manual (downloadable for most models).
Don Hay '92 U-280, The Hayfever Express
Howdy Don and Brett, I'm wondering how often you guys change your air dryer?? I have the cartridge type, and just recently had it replaced, but not sure on replacement frequency?
Thanx, Dave Abel
David,
The drier should last at least 2-3 years before having to replace the cardtridge. Just keep checking the wet tank every once in awhile. As long as no water comes out, the drier should still be good. There is a heater in the drier that is supposed to bake out the moisture from the dessicant.
Don Hay '92 U-280, The Hayfever Express
Rebuild/install factory reman dryer at three years OR if there is ANY sign of water or oil in any tank drain.
Brett
It has probaly been years since it was drained. The lady who owned it 1st said she started it once a week for 3 years prior to my purchase. I have put about 600 hours on the engine in humid Texas .
I will drain it weekly now, see how much water/oil I get out of it.
Then will consider replacement.
Thanks for all the feed back.
Bill Chaplin