I just serviced a TX-100 first stage this evening that had a very strange failure mechanism that I thought might be of interest to the community here. The reg. was brought in for no particular reason but an annual and is owned by one of the staff at the shop. It was serviced last year. It is equipped only with a yoke fitting, so no HP air.
Before anything was done, the IP was checked and found to drift from about 135 psi to about 150 psi in about 1 minute. It "softly" locked up at 150 psi and didn't drift from there.
So, when time came to remove the "valve lifter" on the diaphragm side of the reg., I noticed what looked like a small o-ring surrounding the lifter pin. Once I got to the HP side and removed the seat, I found the problem, but first a brief description of what normally happens to the seat, for those unaware. The seat material seals against a relatively sharp "knife" edge or crown. During use, this seat material takes a set and develops a small indentation (visible) where it rests on the crown.
Now, the problem. The portion of the seat material inside of this normal set was missing, had blown through the crown and ended up on the valve lifter pin!! There was a hole in the seat material so I could see the metal underneath. (I'll see if I can take a picture of it).
I called Aqualung. They've never seen this before and are alarmed. Unfortunately, this reg apparently has been like this for a while because the bare metal surface of the seat came into contact so much with the crown that the knife edge on the crown was gone. So, the whole first stage is going back.
I don't know if we Apeks users should be concerned about this type of failure or not. It's somewhat reminiscent of old Aqualung seat delamination problems, but in this case, the reg didn't fail catastrophically. I'll update when I/if I get a response from Aqualung.
Before anything was done, the IP was checked and found to drift from about 135 psi to about 150 psi in about 1 minute. It "softly" locked up at 150 psi and didn't drift from there.
So, when time came to remove the "valve lifter" on the diaphragm side of the reg., I noticed what looked like a small o-ring surrounding the lifter pin. Once I got to the HP side and removed the seat, I found the problem, but first a brief description of what normally happens to the seat, for those unaware. The seat material seals against a relatively sharp "knife" edge or crown. During use, this seat material takes a set and develops a small indentation (visible) where it rests on the crown.
Now, the problem. The portion of the seat material inside of this normal set was missing, had blown through the crown and ended up on the valve lifter pin!! There was a hole in the seat material so I could see the metal underneath. (I'll see if I can take a picture of it).
I called Aqualung. They've never seen this before and are alarmed. Unfortunately, this reg apparently has been like this for a while because the bare metal surface of the seat came into contact so much with the crown that the knife edge on the crown was gone. So, the whole first stage is going back.
I don't know if we Apeks users should be concerned about this type of failure or not. It's somewhat reminiscent of old Aqualung seat delamination problems, but in this case, the reg didn't fail catastrophically. I'll update when I/if I get a response from Aqualung.