Hi guys, last week I did maintenance on my mk5, at the end the IP was 9.2, when inhaling it drops to 8.4 and recovers almost immediately, no creeps, solid, but surprise, when I check the IP with 30b it drops to 7.9 b, there is a 1.3b difference from a full tank to an empty tank, which is too much, I dived with it and my 156 and everything was normal, I don't notice a difference. I like to leave the I.P in the low range for these regulators, according to the manual an I.P that is too low with the tank almost empty is a devil spring. Would you put some shims on it or would I leave it as it is? I am almost sure that if I raise those 0.7b at low pressure that I am missing, with 200b I will be over 10b of I.P and I don't like that. I think it can stay that way until I get a new spring and try. What do you think? Greetings
Mk5 possible devil spring?
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I think I wouldn’t worry about it but I also think I would be tempted to add one shim.
Hello Lexvil, I agree with you, I am also tempted to put a wedge, but on the other hand, a single wedge would only take it to 8.2, which is negligible and I risk having to change the seat (I mark everything so that it maintains the alignment but you already know that it is difficult to find its initial position with the groove of the seat) Kind regards
I would dive it a while and recheck.
After servicing, piston first stages must "break in" a while before coming back to top performances.
Are you using the newer conical seats or the original white flat seat?
The conical seats come in a set of three different heights, allowing to change the IP simply swapping the seat, without dismounting the whole 1st stage...
After servicing, piston first stages must "break in" a while before coming back to top performances.
Are you using the newer conical seats or the original white flat seat?
The conical seats come in a set of three different heights, allowing to change the IP simply swapping the seat, without dismounting the whole 1st stage...
Hello Angelo, I am using the original plan. In principle I plan to continue diving it until it settles down, but the mk5 is such a good regulator that even in the low range of the tank (being as I said at 7.9 IP) and of course combined with a 156BA, I didn't notice any difference. Lots of air flows even in this big regulator. I intend to get a spring to have as a spare. Regards, Angelo
If your Mk 5 has a LP port on the top, change to that port for your primary regulator. That removes a 90 degree turn in the air flow, and improves the performance (which is why Scubapro put it in).
SeaRat
SeaRat
Hello Juan, yes I knew, but as I said I don't notice a performance problem since I have balanced a second and the mk5 flows a lot of air even at 8 b I.P, it's just curious to know the behavior of the springs after 40 years of use
Greetings
Greetings
axxel57
Contributor
I guess you are diving on your own with no responsibility for others like buddies, students or customers.
If so I think it is acceptable to dive with such a low IP, because also in an unprobable situation when you should be at low tank still quite deep, the 1300 liters per minute that the MK5 still flows at low tank should be enough to get you save to the surface with a still accaptable cracking effort (CE).
If you are not diving alone, you should keep in mind that in case you have to provide a distressed buddy, student or customer in the end of a dive with your air, the dynamic IP could get pretty low, so especially if your Octo should be not balanced, the CE of your and your buddys 2nds will probably increase and will be not really helpful in an emergency situation.
Me personally, I would see that I get the IP a bit higher for that reason.
You can shim the spring or you lube the piston o-rings with Dow 111 or both.
Or you can change the spring.
If it should be difficult to find one in Spain, you can P.M. me, I have have plenty of MK5s and MK5 parts, I could send you one.
BTW, is that 2nd on the pic supposed to be your 156 BA?
If so I think it is acceptable to dive with such a low IP, because also in an unprobable situation when you should be at low tank still quite deep, the 1300 liters per minute that the MK5 still flows at low tank should be enough to get you save to the surface with a still accaptable cracking effort (CE).
If you are not diving alone, you should keep in mind that in case you have to provide a distressed buddy, student or customer in the end of a dive with your air, the dynamic IP could get pretty low, so especially if your Octo should be not balanced, the CE of your and your buddys 2nds will probably increase and will be not really helpful in an emergency situation.
Me personally, I would see that I get the IP a bit higher for that reason.
You can shim the spring or you lube the piston o-rings with Dow 111 or both.
Or you can change the spring.
If it should be difficult to find one in Spain, you can P.M. me, I have have plenty of MK5s and MK5 parts, I could send you one.
BTW, is that 2nd on the pic supposed to be your 156 BA?
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