Diaphragm HP side issues

[_Ralph]

Hi all,

I own a bunch of HOG D1 regs and have done about 20 services on them (total) over the years.

I typically get about 1-2 years of use (100 dives) out of them, before they start showing the same issue, leaking out the body on the HP side.

Never had an IP issue (one did rise about 3psi and lock up after 10 seconds), but they all bubble out.

Since it’s that weird time of year for me where things are starting to ice over (too thick to safely dive, too thin to walk out and cut a hole), starting to do some more service work in the down time.


Curious if there might be something I’m not doing as correct when cleaning or assembling them at service?

Hints/ideas?

Thanks!!

_R

 

[buddhasummer]

Have you closely inspected the HP crown (orifice) under a loupe? Ditto the seat?

 

[Luis H]

I am not following exactly what you mean by this: “leaking out the body on the HP side”.

Is it leaking around the edge of the HP diaphragm?

It should be fairly easy to determine the gas path if the bubbles are consistently coming from the same location.

If it is leaking around the diaphragm edge, that could be that the diaphragm is taking a set after some time. If this is the case, the next time it happens just try tightening the clamping down nut on the diaphragm (and readjust the IP). See if that stops the leak before you start tearing anything apart.



As a disclaimer, I am not familiar with this particular diaphragm regulator, but I am guessing that it is probably just like most other diaphragm first stages.

 

[rsingler]

Never had an IP issue (one did rise about 3psi and lock up after 10 seconds), but they all bubble out.

When you have a leak from a diaphragm reg that does NOT affect IP, you need to look at the other sealing surfaces.
IP creep is a function of a leak at the orifice/HP seat interface, OR a leak at the tiny stem oring for the poppet (in red below), with HP air leaking thru the balancing mechanism to the low pressure side.

The bubbling I think you are describing comes from a flaw in the interface in one of the two orings below:

HP bubbling from the edges of the poppet holder (a high pressure side assembly) has to be escaping past orings #1 and/or #2 above. Consider either an oring problem, or a scratch in the land at #2.

If by bubbling, you mean bubbles escaping around the environmental diaphragm, then the leak is at the diaphragm seal, because the environmental diaphragm is only hand tight.

If you mean bubbling around behind the hand wheel for DIN, or the base of the yoke, the problem is likely a scratch in the land where the yoke or DIN bolt meets the body, on the body side of the regulator or in the land where the bolt oring sits.

 

[Luis H]

If the leak is from under the IP side of the HP diaphragm (it should actually be called an IP diaphragm), the leaking air will normally travel past the threads (through the threads) and out the side of the body, at the joint between the main body and the large threaded piece that clamps the diaphragm.


@rsingler, From looking at that diagram, if O-ring #2 is leaking, it will also manifest itself as an IP creep. Unless there is something not shown correctly in that diagram, O-ring #2 is sealing between the HP (dark blue) and Low pressure (lighter blue).

 

[rsingler]

From looking at that diagram, if O-ring #2 is leaking, it will also manifest itself as an IP creep. Unless there is something not shown correctly in that diagram, O-ring #2 is sealing between the HP (dark blue) and Low pressure (lighter blue).

Luis, you are right. I see now that this diagram is similar to, but not the same as the HOG reg. The HOG poppet has a central channel, and there's a back door balancing channel similar to this diagram with a solid poppet stem. So bubbling from the HP retainer assembly without IP creep would mean a leak at only o-ring #1.

 

[_Ralph]

If the leak is from under the IP side of the HP diaphragm (it should actually be called an IP diaphragm), the leaking air will normally travel past the threads (through the threads) and out the side of the body, at the joint between the main body and the large threaded piece that clamps the diaphragm.

I believe this is where it usually leaks, either the main body threads (that houses the HP side) or the environmental cap..

_R

 

[Couv]

This thread reminds me of why, when rebuilding a diaphragm first stage, it is a good idea to complete the assembly of the high pressure side and do a simple leak test before continuing with the IP/low pressure side.

@_Ralph Disassemble the l/p/IP components, i.e. remove items 11 through 18 and 32 through 34. Pressurize the reg with the open side up. Put a few drops of water in the hp pin hole and check for bubbling. If bubbling occurs, there is something amiss in the hp side-the seat, balance chamber, balance chamber seal, etc. Any discrepancy must be corrected before proceeding. If no bubbling, install the pin and pad-give it a little press to blow the water out. Now brush soapy water over the rest of the pressurized body and inspect for leaks. Correct as necessary.

 

[_Ralph]

This thread reminds me of why, when rebuilding a diaphragm first stage, it is a good idea to complete the assembly of the high pressure side and do a simple leak test before continuing with the IP/low pressure side.

@_Ralph Disassemble the l/p/IP components, i.e. remove items 11 through 18 and 32 through 34. Pressurize the reg with the open side up. Put a few drops of water in the hp pin hole and check for bubbling. If bubbling occurs, there is something amiss in the hp side-the seat, balance chamber, balance chamber seal, etc. Any discrepancy must be corrected before proceeding. If no bubbling, install the pin and pad-give it a little press to blow the water out. Now brush soapy water over the rest of the pressurized body and inspect for leaks. Correct as necessary.

View attachment 555802

Good advice, although the leak doesn't develop until after a year of use, and per the service instructions, it says to build the diaphragm side first...
Unless you mean when it starts bubbling after a year, disassemble that part and check for the leak. I usually mangle diaphragm washer in the process of removing it.

_R

 

[Couv]

per the service instructions, it says to build the diaphragm side first...

Most service manuals do in fact say that; however if you follow those instructions you are missing an opportunity to check the integrity of the HP components previously mentioned. You can also install the push pin and pad and cycle the hp valve a few times. Why wait until you have the the diaphragm and low pressure components in place to find out you have a hp issue?

Unless you mean when it starts bubbling after a year, disassemble that part and check for the leak. I usually mangle diaphragm washer in the process of removing it.

Well I mean during normal service, but no reason not to back up to this stage when troubleshooting a problem.

Do you currently have a first stage that is exhibiting a leak?