Question Wanted Hog D3 service manuals

[Tom_Ivan]

Hi All

I was wondering if anyone has a digital copy for HOG D3 service manuals that they would be willing to share with me?
I understand that you can do the training and get them but I wouldn't mind access to the manuals anyway.


Thanks

 

[trimmatters]

How did this one pan out?

 

[trimmatters]

Hey team

I ask this question to help a mate troubleshoot

Recently serviced D3 first stage, but it has come back with the IP creeping.

I am familiar with adjusting the IP outright, but not troubleshooting why the IP might be creeping.

Servicing regs here isnt as simple as dropping them to a shop, it involves shipping across the country etc. Just looking to understand the issue better so can ask more pointed questions.

 

[profmason]

Not helping, but yesterday both of my D3s have IP creep after being out of the water 116 days. They are 18months old and have 180 dives. My D1 and D2 are fine. I looked at the deep6 manual and peters book, but am in Mexico so will wait to figure it out. Jade scuba up in Seattle is working to put together a Hog service class in july.

 

[rsingler]

IP creep in a diaphragm reg is more complex than in a piston.
In a piston, there is only ONE source of true IP creep (as opposed to other leaks): a seal failure between the piston knife edge and the seat.

And indeed in a diaphragm, that is the first place most folks look.
1) They just put in a new seat.
When the leak doesn't stop, maybe they look in the reg body and see that a previous technician has scratched the volcano by using a metal tool (arrgh!). For many diaphragms, the reg is now toast. For the HOG D3,
2) you can just replace the volcano orifice.

But DIY dive techs are frugal.
If you inspect the seat face and it's smooth; if you inspection the volcano and it's perfect, what else could be the problem?

A seal between the tank pressure and the IP compartment(s) is typically made by an oring.
Thus, you now have THREE more potential leak points for each o-ring:
a) a nicked/damaged/cracked o-ring, so
-- 3) replace it, or
b) a scratched land for the o-ring on the reg body side, so
-- 4) you reg is once again toast, or
c) a scratched land on the part side, so
-- 5) polish the HP seat shaft or replace the HP seat;
-- 6) polish the land inside the balance chamber (very difficult), or replace the balance chamber;
-- 7) polish the replaceable volcano orifice land or replace the volcano

The solution to IP creep in a diaphragm is sequential, careful inspection of every pressure interface. Or, just become a piston diver.

Thread How to restore a Diaphragm First Stage with IP Creep

 

[trimmatters]

IP creep in a diaphragm reg is more complex than in a piston.
In a piston, there is only ONE source of true IP creep (as opposed to other leaks): a seal failure between the piston knife edge and the seat.

And indeed in a diaphragm, that is the first place most folks look.
1) They just put in a new seat.
When the leak doesn't stop, maybe they look in the reg body and see that a previous technician has scratched the volcano by using a metal tool (arrgh!). For many diaphragms, the reg is now toast. For the HOG D3,
2) you can just replace the volcano orifice.

But DIY dive techs are frugal.
If you inspect the seat face and it's smooth; if you inspection the volcano and it's perfect, what else could be the problem?

A seal between the tank pressure and the IP compartment(s) is typically made by an oring.
Thus, you now have THREE more potential leak points for each o-ring:
a) a nicked/damaged/cracked o-ring, so
-- 3) replace it, or
b) a scratched land for the o-ring on the reg body side, so
-- 4) you reg is once again toast, or
c) a scratched land on the part side, so
-- 5) polish the HP seat shaft or replace the HP seat;
-- 6) polish the land inside the balance chamber (very difficult), or replace the balance chamber;
-- 7) polish the replaceable volcano orifice land or replace the volcano

The solution to IP creep in a diaphragm is sequential, careful inspection of every pressure interface. Or, just become a piston diver.

Thread How to restore a Diaphragm First Stage with IP Creep

outstanding

tyvm

 

[Jim Lapenta]

IP creep in a diaphragm reg is more complex than in a piston.
In a piston, there is only ONE source of true IP creep (as opposed to other leaks): a seal failure between the piston knife edge and the seat.

And indeed in a diaphragm, that is the first place most folks look.
1) They just put in a new seat.
When the leak doesn't stop, maybe they look in the reg body and see that a previous technician has scratched the volcano by using a metal tool (arrgh!). For many diaphragms, the reg is now toast. For the HOG D3,
2) you can just replace the volcano orifice.

But DIY dive techs are frugal.
If you inspect the seat face and it's smooth; if you inspection the volcano and it's perfect, what else could be the problem?

A seal between the tank pressure and the IP compartment(s) is typically made by an oring.
Thus, you now have THREE more potential leak points for each o-ring:
a) a nicked/damaged/cracked o-ring, so
-- 3) replace it, or
b) a scratched land for the o-ring on the reg body side, so
-- 4) you reg is once again toast, or
c) a scratched land on the part side, so
-- 5) polish the HP seat shaft or replace the HP seat;
-- 6) polish the land inside the balance chamber (very difficult), or replace the balance chamber;
-- 7) polish the replaceable volcano orifice land or replace the volcano

The solution to IP creep in a diaphragm is sequential, careful inspection of every pressure interface. Or, just become a piston diver.

Thread How to restore a Diaphragm First Stage with IP Creep

On the older D3s, you could replace the volcano orifice, like the ones produced the first year they were made.
The ones after that had the orifice machined into the body itself.
They went to this after too many people were screwing up the replacement.
Nicking the o-ring, or, in some cases, even forgetting it or reusing the old one. Others would drop the orifice and not realize it was nicked.
The D3 would start to creep after a time if the seat wasn't installed and broken in correctly.
The correct procedure for all HOG regs is to set the initial IP at 130-135 or so at 500 PSI.
Cycle the reg a minimum of 25 times. I always taught closer to 50 was best.
Then attach it to a cylinder or increase the supply pressure (if using an adjustable one) to 1500 PSI and cycle it again another 25-50 times. You will see an IP drop (usually around 5-8 PSI). Don't touch the adjustment screw.
Next attach to or increase supply pressure to 3000 PSI. This may result in a 10PSI drop.
At this point, increase the IP by turning the adjustment screw while inhaling or pushing the purge button, 1/16 to 1/8 of a turn at a time.
Let off the purge or stop inhaling. Never turn the adjustment screw with the reg closed (air not flowing through the second stage). Only turn the screw while inhaling or pushing the purge.
Do this until you get back to 135 PSI at 3000 PSI.
Since most of my students and I dived colder water, we would set the IP between 131 and 133.
After a dive or two, you might see a drop of another 2-3 PSI as the seat develops a groove.
It's ok to bump it up a little back to the 133-135 at 3000 PSI.
I probably serviced a couple hundred D3s before I retired, not including my own. Out of all of those, I think I had one that needed to be redone. It turns out the user tried to back down the IP because it was reading 140 at 500PSI, which is what it's supposed to do.
I also trained over 50 students to service their own regs and a few shop techs as well.
Increasing IP is ok on a newly serviced reg. Backing it down should not be done because the seat has already taken a set and there is a risk of messing with that. Resulting in creep or even seat failure in rare instances.

 

[trimmatters]

Thank you for the write up!

Back on to my own reg dramas here... curious how the comment to not back the IP down plays into using these as first stages for O2 on a CMF style CCR. I picked up a new D2 first stage and blanked it for my CC training and set the IP to a flow which was appropriate at the time.

After changing hte in-line filter and improving technique over the next year, I had to back off the IP. Very small adjustment, less than a bar of pressure I think.

Is there anything I should be thinking about there in future?

Backing it down should not be done because the seat has already taken a set and there is a risk of messing with that.

 

[happy-diver]

Backing it off anyway, and finding a stronger spring for if you decide to go needle valve

 

[rsingler]

I don't share the concern over reducing IP with the adjusting screw. Put it at whatever pressure you like. That's particularly relevant for a CCR O2 first stage.

Think about what happens when you adjust a diaphragm. It's NOT like a Mk25, where screwing in the hex to reduce IP moves the seat. With that reg, if you reduce IP with the valve pressurized and closed, the hex forces the seat against the piston knife edge, and damages or cracks it.

In contrast, a diaphragm's mechanism is completely different. When you screw in the adjuster with the reg pressurized, what happens? The mainspring adds a little more pressure on the pin, overcoming IP and pushing the valve open. You can't hurt the valve seat that way.

When you try to decrease IP by unscrewing the adjuster with the reg pressurized, the valve seat is already closed against the volcano. Backing off the spring an eighth of a turn doesn't do anything to the pin. Yeah, if you unscrewed it multiple turns with it pressurized, the pin might slip out of its pocket in the carrier (if it's a two piece construction unlike the HOG), but nobody's talking about that huge an adjustment before you purge the second stage. In fact, Scubapro has you check the seal of your seat in the Mk17 before you even add the diaphragm and mainspring! In other words, unopposed tank pressure is not going to damage the seat. Shop techs have been "slam setting" the first stage seat for decades, not that I agree with it.

What else is happening when you unscrew the mainspring a little? Well, you now have a few psi less counterpressure on the plate that is pushing on the diaphragm, and the diaphragm is exposed to a slight imbalance in pressures: original IP under the diaphragm; slightly less counterpressure above the diaphragm. That theoretically puts a little stress on the diaphragm, but it's insignificant if you're only unscrewing the adjuster an eighth of a turn. We're talking 3-10 psi. The diaphragm moves perhaps 0.1mm. Insignificant. It won't "tear loose", and in fact undergoes far larger movement in the other direction with dynamic IP swings when you're breathing off a near-empty tank.
The bigger issue is that when you're down-regulating IP this way, you won't see any change on the IP gauge until you purge the second stage, because the valve is closed and the IP can't change. The compartment is still sealed.
That's the real reason to unscrew a little, purge, unscrew a little, purge, etc. It's so you see the results of your work. You're not going to twist the seat and damage it, or hurt the diaphragm with tiny adjustments. Since the seat doesn't rotate when you rotate the adjuster (the diaphragm's in the way) then you won't change the match between the volcano and the seat impression. "Not reducing IP" in a diaphragm is an urban myth resulting from conflation with pistons. It's not a Mk25.
If you disassemble the components and reassemble (with a new orientation of the HP seat on the volcano), you might get a little drift until the seat re-conforms to the microscopic irregularities in the volcano, but it should seal up after a few hundred cyclings. It's possible that it won't, and that you'll need a new seat. But just readjusting IP without disassembly won't hurt the reg.