Scubapro r108

[Open Ocean Diver]

Seeking knowledge....

So I bought a parker vacuum pump 2.5 L per minute and set up a fixture to test the cracking effort of my regulators. I use a variable DC power supply to vary the volume of air, works well.

One thing I noticed the volume of air to create a vacuum to crack open the demand valve is twice as much on the scuba pro 108HP versus the 156 and D400.

All set to 108 = .6, 156 = .9, 400 = .5 inches of water.

- question does anyone know why this is? Is it maybe due to the difference in case geometry?

thanks,

Kevin

 

[Caveeagle]

Case volume would certainly make a difference, but would t expect it to be that much. Could it be taking a little more time for one of the exhaust valves to seal? Do they both hold vacuum the same with the gas supply off?

 

[Open Ocean Diver]

Yes the vacuum test subjectively of course seem to be the same. It may not be twice the volume but the voltage needed is double 3 to 6 Volts on my pump. Assuming it is linear. I switched the pump around and both regulators 2.5 L per minute wasn't enough to open the exhaust valve... Ended up Burning my pump out. Manually both exhaust valve open around 2-4 inches of water.

 

[Rusty Shackleford]

How close is the lever arm to touching the diaphragm?

 

[GJC]

Seeking knowledge....

So I bought a parker vacuum pump 2.5 L per minute and set up a fixture to test the cracking effort of my regulators. I use a variable DC power supply to vary the volume of air, works well.

One thing I noticed the volume of air to create a vacuum to crack open the demand valve is twice as much on the scuba pro 108HP versus the 156 and D400.

All set to 108 = .6, 156 = .9, 400 = .5 inches of water.

- question does anyone know why this is? Is it maybe due to the difference in case geometry?

thanks,

Kevin

Your vacuum pump is way too small. A human inhales at around 15 to 30 liters per minute and up to 60 when working hard.

 

[Open Ocean Diver]

How close is the lever arm to touching the diaphragm?

I went through the standard set up procedure, but maybe I should check it. Thanks

 

[Open Ocean Diver]

Your vacuum pump is way too small. A human inhales at around 15 to 30 liters per minute and up to 60 when working hard.

The volume is just enough to crack open the demand valve, works well.

 

[Open Ocean Diver]

So here’s the update fixed my vacuum pump had to replace a suppressor that blew when I set the voltage to high. Measured the case volume by filling the regs with water, comparing the 108 and 109, of course this is all approximate... 109 - 55 mL of water and the 108 - 75ml. After wetting the regulators the volume of air measured (bought a cheap flow metre), 1.5 L/min to reach their perspective cracking effort. Interesting when they were both dry the 108 needed twice as much volume to reach the same vacuum to crack the demand valve. Albeit they both tested fine with the subjective dry vacuum test. Fun experiment.