Pressure Relief Value O'ring replacement?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

SentinelAce

ScubaBoard Sponsor
ScubaBoard Sponsor
Messages
228
Reaction score
50
Location
Ohio
# of dives
500 - 999
Does anyone have a tip on how to replace this oring? I don't want to mess it up because it gives approximate setting for the relief valve. I'm not sure where the O'ring is located but it's leaking from the top.

capture.png
 

iain/hsm

Contributor
Messages
827
Reaction score
451
Location
uk
It does that (leaks) when the pressure in that black tower aproaches the presure setting on the relief valve.
That is what it is designed to do. Once the set pressure is exceeded the HP seat on the relief valve then lifts and dumps the excess pressure out until the pressure is lowered and the PRV re seats itself back on it seat.

Over time it may leak at under the set pressure but that black filter tower in the picture is less than 10 years old and the set pressure looks awfully low judging by the amount of spare thread poking out above the set nut.
My guess is its new and has never been set up properly.

The 0-ring your asking about is an aircraft spec Dupont Viton material A size 006 and is 90 shore hardness
 

SentinelAce

ScubaBoard Sponsor
ScubaBoard Sponsor
Messages
228
Reaction score
50
Location
Ohio
# of dives
500 - 999
It does that (leaks) when the pressure in that black tower aproaches the presure setting on the relief valve.
That is what it is designed to do. Once the set pressure is exceeded the HP seat on the relief valve then lifts and dumps the excess pressure out until the pressure is lowered and the PRV re seats itself back on it seat.

Over time it may leak at under the set pressure but that black filter tower in the picture is less than 10 years old and the set pressure looks awfully low judging by the amount of spare thread poking out above the set nut.
My guess is its new and has never been set up properly.

The 0-ring your asking about is an aircraft spec Dupont Viton material A size 006 and is 90 shore hardness

Jim Sheldon says if it pops off so many times, the O-ring has to be replaced. How do you adjust this? I have it set to 3600 PSI but now it's beginning to leak out around 3200 or less without popping off. It just leaks out the top
 

iain/hsm

Contributor
Messages
827
Reaction score
451
Location
uk
Jim Sheldon says if it pops off so many times, the O-ring has to be replaced. How do you adjust this? I have it set to 3600 PSI but now it's beginning to leak out around 3200 or less without popping off. It just leaks out the top

I would agree with him but for the possibility (from your photo) that this is pretty much a brand new relief valve.

Another option is when you were adjusting the thing you cranked down that adjustment screw with a 5/16 allen key while under pressure and scored up a brand new ring causing the leaks in the first place. Trick is to adjust with no pressure inside, then presurize and check, then drain again before re adjusting if your increasing up the set pressure.
This keeps the seat and seal in place and stops you gouging out chunks of o-ring rubber or scoring the sort seat as you jack the adjustment thread round and around while still under 3600 psi of pressure load.
 

SentinelAce

ScubaBoard Sponsor
ScubaBoard Sponsor
Messages
228
Reaction score
50
Location
Ohio
# of dives
500 - 999
I would agree with him but for the possibility (from your photo) that this is pretty much a brand new relief valve.

Another option is when you were adjusting the thing you cranked down that adjustment screw with a 5/16 allen key while under pressure and scored up a brand new ring causing the leaks in the first place. Trick is to adjust with no pressure inside, then presurize and check, then drain again before re adjusting if your increasing up the set pressure.
This keeps the seat and seal in place and stops you gouging out chunks of o-ring rubber or scoring the sort seat as you jack the adjustment thread round and around while still under 3600 psi of pressure load.

This unit came like this a couple years ago. I have never attempted to remove it. So it's not scored up at all. Is there a guide or video on how to replace it?
 

iain/hsm

Contributor
Messages
827
Reaction score
451
Location
uk
You asked for a video dont blame me LOL

Although the spares kit is a $16 item, you may only need the 0-ring
but for what its worth I would first simply back off the locking nut (ring) and
tighten down the adjusting barrel thread about half a turn.
Granted it will increase the set lift pressure but for a test it will let you verify
if its a genuine leak or just badly set too low.

Data sheet and drawing enclosed below.

https://valvesandregulators.aquaenvironment.com/Asset/0933_130802_OM_504.pdf
 

SentinelAce

ScubaBoard Sponsor
ScubaBoard Sponsor
Messages
228
Reaction score
50
Location
Ohio
# of dives
500 - 999
You asked for a video dont blame me LOL

Although the spares kit is a $16 item, you may only need the 0-ring
but for what its worth I would first simply back off the locking nut (ring) and
tighten down the adjusting barrel thread about half a turn.
Granted it will increase the set lift pressure but for a test it will let you verify
if its a genuine leak or just badly set too low.

Data sheet and drawing enclosed below.

https://valvesandregulators.aquaenvironment.com/Asset/0933_130802_OM_504.pdf

and I tighten that with an allen wrench then tight the locking nut?
 

Jimchris

Support your local dive center
ScubaBoard Supporter
Messages
144
Reaction score
57
Location
Washington State
# of dives
1000 - 2499
I've replaced the o-ring with 90 durometer polyurethane when they started to leak in the past.
 
https://www.shearwater.com/products/swift/

Top Bottom