HELP me fill my SCBA with a Yong Heng

[badger5th]

General principal try to get the air to go "uphill" to the tank as much as possible. Compressor low, pump up into the filter, continue up to the tank. Try to keep purge valves at the low points for each component in the chain. These steps keep water low by gravity and allow better bleeding.

 

[rcs9250]

One thing I don’t see on all the YH’s and copies and anything short of a legitimate scuba compressor is an item called a PMV (Pressure Maintaining Valve). Scuba compressors MUST have one right after the molecular sieve so that the sieve does its job. A PMV is an adjustable device that is set somewhere between 120-160 bar (1740-2320 psi).
The reason for it is that for the sieve to remove moisture, the air needs a “dwell” time in the sieve. The PMV makes that happen. Dry air does not leave the sieve drier until the PMV’s set pressure is exceeded. Why they aren’t used or mentioned when used on the YH’s and similar is a mystery to me. All Alkin’s, Bauer’s, Coltri’s and other scuba compressors come equipped with molecular sieve driers and PMV’s.
I will also add though that a lot of people are running YH’s and similar with out any issues, I think ??
My first compressor was an Omega Air Charger that I added a sieve that I got from Air Tanks For Sale. The photo shows my set up that I fabricated. The gold colored item is the PMV.

 

[Airgunmann]

Use lots of ice and take your time with it filling a big tank from empty can be hard on them

 

[Scotty1]

Don’t forget that the motor windings also heat up with time, and are not shown on your temp gauge. When I ran mine to fill bottles, I had air blowing on the back of the motor as well. Feel the case after 10 minutes, and again at 20 and compare. The built-in fan is not very effective.

 

[mb94952]

How come no water lines, water pump, or more importantly, water?

Allen

Oh this is just a mockup to see if I have the correct lines going, etc. I will have the water when I actually do it. Thanks for asking, though.

 

[jking]

Good point. I do monitor the temp carefully and don't let it get too hot. I use very cold water, too, but I need to upgrade to a 5 gallon bucket like most of you do.

So what is the alternative then to stopping it @jking so I don't have to repressurize the lines ?

I rigged my filter up with a check on the outlet to save all my pressurized air on everything past that in case of a sudden leak on the compressor side. It also allows you to open the fill bottle and then start the compressor anytime.
Then it dawned on me the check could go on the inlet side so if you wanted to turn the compressor off all you need to depressure before a restart would be the short hose coming off the compressor. Using a check like this.

 

[JimD]

I agree completely about the value of a check valve. Another benefit is it doesn't matter when you open the bottle valve. Air cannot flow from the bottle to the YH overpressurizing it as it is attempting to get up to pressure. I still start the pump first and let it build for a few seconds but I don't try and time the valve opening to the point the pump pressure matches the bottle. It makes things a lot easier. I got mine off Amazon (and my male to male too)

I also think having the filters vertical ABOVE the YH is much better if you can arrange it. The air will cool going through the filter and moisture will come out. If you allow it to drain back to the YH it will blow out when you open the vent. I open it approximately every 5 minutes. I have color change beads in my extra filter and I rarely need to change them, they see little moisture - despite the really high humidity here in the summer. No signs of moisture in my tank or guns.

I have an inexpensive computer radiator on my YH bucket with a couple fans on it. I normally can pump my 45 minute SCBA tank from around 3000 to back up around 4000 in about 15 minutes with the temperature of the head not going above 63 C. In the winter it will stay below 60. I may use ice more in the summer, it helps. My bucket is closed and I am running distilled water with water wetter in it. But ice packs or frozen soda bottles can still be added to the coolant if I snap the lid off the bucket. It's really nice not to have to make multiple runs. But even if you need more than one, the head temperature will drop much faster with the radiator.

 

[bigHUN]

Also don`t forget the tank temperature. Refilling from 200 bar to 300 bar will warm up a tank as well. Usually I am taking at least 15 minutes between runs.
Go for a coffee, read the News, duno, but let all cool down nicely.

 

[JimD]

If you put on a check valve on the output of your last filter, like I have, it would be good not to dead head the line coming from that filter to test your compressor. Either disconnect the filter from the YH to the extra filter and dead head there or connect to your bottle but leave it's valve closed. If you dead head the line after the filter, you will have no way to bleed it.