Question IP Too High, so what? and why?

[Jim Lapenta]

IP goes up with break in, not down.

Actually as the seat takes a set, IP will drop. This is why I break them in starting at 500 then move to 1500, and finally 2700-3000.
You can see the IP drop after installing it on the HP supply as the seat is breaking in. Depending on how many times you cycle it, it may also drop a few (2-3 PSI) after the 1st dive.
I initially set all IP's at 135 per the manual at 500 PSI on customer regs and expect it to settle in at 133-134 and stay there after attaching to the HP supply. Then it gets adjusted up to 135-136. It's standard on the regs I service and wrote the service manuals to do the final adjustment on the HP supply.
Because I dive colder water usually, I set my own at 133-134 initially and it settles in at 131-132.

 

[lexvil]

This whole thread is a great argument on why it’s good to own your own Regs.

 

[Centrals]

This whole thread is a great argument on why it’s good to own your own Regs.

We all have different ideas!
A smart tec will just set what the manufacturers recommended. No liability.

 

[AfterDark]

Actually as the seat takes a set, IP will drop. This is why I break them in starting at 500 then move to 1500, and finally 2700-3000.
You can see the IP drop after installing it on the HP supply as the seat is breaking in. Depending on how many times you cycle it, it may also drop a few (2-3 PSI) after the 1st dive.
I initially set all IP's at 135 per the manual at 500 PSI on customer regs and expect it to settle in at 133-134 and stay there after attaching to the HP supply. Then it gets adjusted up to 135-136. It's standard on the regs I service and wrote the service manuals to do the final adjustment on the HP supply.
Because I dive colder water usually, I set my own at 133-134 initially and it settles in at 131-132.

Sounds very much like what I do, thanks Jim.

 

[Centrals]

8.5 bars for all my Apeks regs.
8 for my 100% O2.

 

[AfterDark]

You meant UNDER the max

No, I posted over because that's what I do.

 

[AfterDark]

One reason why you need a service manual before servicing a reg. As a general rule anything above 145 is high. There are exceptions like Poseidon where it can go to 170ish... you also need to know at what supply pressure you need to st the 1st stage...

I wanted to know what the OP sees as too high. I have a double hose that I tuned to 150 psi IP and it works great, so too high isn't always too high it just may seem that way.

 

[p_kos]

Actually as the seat takes a set, IP will drop. This is why I break them in starting at 500 then move to 1500, and finally 2700-3000.
You can see the IP drop after installing it on the HP supply as the seat is breaking in. Depending on how many times you cycle it, it may also drop a few (2-3 PSI) after the 1st dive.
I initially set all IP's at 135 per the manual at 500 PSI on customer regs and expect it to settle in at 133-134 and stay there after attaching to the HP supply. Then it gets adjusted up to 135-136. It's standard on the regs I service and wrote the service manuals to do the final adjustment on the HP supply.
Because I dive colder water usually, I set my own at 133-134 initially and it settles in at 131-132.

I should have specified piston vs diaphragm. I mostly dive pistons so that’s my bias. On a piston reg it goes up as the seat wears. The groove puts the piston further away from the seat and the spring has to be compressed more for the piston to reach the seat resulting in higher IP. Piston 1st stages are “downstream” valves and diaphragm 1st stages are “upstream” valves so they behave differently. I know you’re a diaphragm guy, and since we’re here, my Deep6 Signature 1st stage has an IP increase of 10 psi going from 3000 psi tank to 500 psi tank (135 up to 145 psi IP), not very balanced, what’s up with that?

 

[halocline]

I should have specified piston vs diaphragm. I mostly dive pistons so that’s my bias. On a piston reg it goes up as the seat wears. The groove puts the piston further away from the seat and the spring has to be compressed more for the piston to reach the seat resulting in higher IP. Piston 1st stages are “downstream” valves and diaphragm 1st stages are “upstream” valves so they behave differently. I know you’re a diaphragm guy, and since we’re here, my Deep6 Signature 1st stage has an IP increase of 10 psi going from 3000 psi tank to 500 psi tank (135 up to 145 psi IP), not very balanced, what’s up with that?

I don't think you and Jim are talking about the same thing. Both piston and diaphragm regs would behave the same with regards to IP and seat wear. The upstream/downstream bias determines the way tank pressure affects IP, but not the way seat wear affects IP. In both cases, if there is a deepening groove in the soft seat, the spring will need to be compressed a bit more to form the seal, which means IP must go up.

Perhaps Jim is talking about the common thing that happens with a brand new seat, which is that until there is a 'set' in the seat that forms an excellent seal with the hard orifice (or piston), the seating force (which is IP) is a little higher. Then, when the seat breaks in a bit and there's a good mating between seat and orifice, it takes less force to form a leak-proof seal. So you might pressurize a freshly serviced 1st stage and initially see that IP creeps a bit or is a little higher, but after a few dozen cycles and maybe several minutes pressurized, it stabilizes a bit lower.

To be honest, I'm not sure exactly what people on this thread are referring to with regards to seat wear causing an increase in IP. Personally, after working on regulators for about 20 years, I have rarely seen IP simply rise as the seat wears. What I experience is that IP starts to creep a little, becoming less stable as the seat wears. As the seal between seat and orifice (or piston) degrades. IP does go up, but in my experience it's usually more like a mushy lock up with some creep, and then finally settling at a slightly higher number, but not consistently. Maybe other people have different experiences.

 

[p_kos]

I should have specified piston vs diaphragm. On a piston reg it goes up as the seat wears. The groove puts the piston further away from the seat and the spring has to be compressed more for the piston to reach the seat resulting in higher IP.

I don't think you and Jim are talking about the same thing. Both piston and diaphragm regs would behave the same with regards to IP and seat wear. The upstream/downstream bias determines the way tank pressure affects IP, but not the way seat wear affects IP. In both cases, if there is a deepening groove in the soft seat, the spring will need to be compressed a bit more to form the seal, which means IP must go up.

Perhaps Jim is talking about the common thing that happens with a brand new seat, which is that until there is a 'set' in the seat that forms an excellent seal with the hard orifice (or piston), the seating force (which is IP) is a little higher. Then, when the seat breaks in a bit and there's a good mating between seat and orifice, it takes less force to form a leak-proof seal. So you might pressurize a freshly serviced 1st stage and initially see that IP creeps a bit or is a little higher, but after a few dozen cycles and maybe several minutes pressurized, it stabilizes a bit lower.

To be honest, I'm not sure exactly what people on this thread are referring to with regards to seat wear causing an increase in IP. Personally, after working on regulators for about 20 years, I have rarely seen IP simply rise as the seat wears. What I experience is that IP starts to creep a little, becoming less stable as the seat wears. As the seal between seat and orifice (or piston) degrades. IP does go up, but in my experience it's usually more like a mushy lock up with some creep, and then finally settling at a slightly higher number, but not consistently. Maybe other people have different experiences.

That makes sense. I still have lots to learn.