Poseidon 3790 1st stage IP creep

[Pipi Fakidomiti]

Hello all
I have never had the courage (or need) to start a topic really, and I am a new member although I have been reading the site a lot for the past years.
I just wanted to set a question out to anybody that might be able to help me if they are so kind.
I am sure somebody may have asked the same thing in the past but I couldn't find anything related really.
I serviced a poseidon 3790 1st stage today and I did everything according to the manual. Problem is that when I am connecting an IP pressure gauge and my jet stream I am getting very bad creep from the 1st stage that does not stop until the pressure relief valve opens up.
I have set the IP correctly and I overhauled the reg again replacing the viton oring again on the valve seat (in case it was defective) but it is still creeping heavily at the same rate.
I am a bit stuck really, I am not new to reg servicing as being a tech diver I mostly service my regs myself and I always have very good results really. I have serviced everything from Scubapro to Apeks and from Dacor to Sherwood without any probs so I am a bit lost really...
I know the jet stream is an upstream 2nd stage but the problem definitely stems from the 1st stage as the second stage would not affect my primary IP?
There is no freeflow from the 2nd stage at all until the pressure builds up very high(over 15 bar). My purges are absolutely fine as well.
When I had a similar problem with a scubapro mk25 I had to replace the piston as there was a hairline nick on the stem, this worked fine. I can not see anything wrong with the seat however on the poseidon .
Any help would be appreciated really.
I used original poseidon service kits and I have done everything according to the manual so I dont know what might be wrong.
Thanks very much in advance for your answers (if there are any of course).
Kindest regards
Dimitris

 

[tbone1004]

you may have a scratch on the hp seat, can happen randomly and I've had a couple that are junk. Thankfully they are inexpensive to purchase separately. Try it with a different second stage as well as the jetstreams can be a bit weird when trying to set a first stage

 

[Pipi Fakidomiti]

Thank you very much for your answer my friend.
I think you are absolutely right, I compared the old and new seat and the new one has a bigger slit on the side ( u probably know what I mean). So I changed the seat and used the old one ( I know it is not best but very often in the army we used to do that if it was not damaged) obviously with a new viton oring and now the 1st stage locks beautifully at 8.5 bar with the jetstream 2nd stages.
Why do you say it is tricky with the jet stream? Because it is upstream or due to the ridiculous purge?
As well where can I source the HP seats not being a poseidon tech? Probably Germany?
Thanks again for your kind answer though, you have been very helpful indeed.
Kindest regards
Dimitris