Enraptured of the Deep
Contributor
I am having trouble with a regulator with low IP. I just rebuilt a new-to-me Scubapro Mk10 that appears not to have been serviced since the turn of the century -- the "next service sticker says, "Sep. 00."
The seller had noted that he couldn't get a pre-servicing IP on it, so I did not test IP myself before servicing. When I took it apart, there was one shim in it. I added a second 0.010" VDH shim (one at each end of the spring) and put it all back together.
After a couple of hundred purge cycles, I got a steady IP of 125 at 3000 psi. The problem came when I checked the IP at 300 psi. It was down around 110. I opened it up, replaced the two 0.010" shims with THREE 0.015" shims (one at the base of the piston and two at the top), but that brought the IP to only 119 at 300 psi.
By the way, I did mark the HP seat cover and regulator body to ensure that the HP seat was in the same position before and after reassembly. Also, just to be sure that nothing else in the system was leaking air, I took off all hoses except for the HP hose with the SPG and the LP hose with the IP gauge (with over-pressure valve).
The Mk10 technical guide says low IP at 3000 and 300 psi is a sign of a weak spring and says one should not put more than three shims in a Mk10.
Is there any chance I have the shims arrayed incorrectly? I have seen a number of posts on this forum suggesting it is best to have at least one shim at each end of the spring (if more than one shim is needed), but the Scubapro technical literature shows all three shims in a Mk10 at the end of the spring near the knife edge.
Is my only option is to replace the piston spring? If so, where can I obtain one???
The seller had noted that he couldn't get a pre-servicing IP on it, so I did not test IP myself before servicing. When I took it apart, there was one shim in it. I added a second 0.010" VDH shim (one at each end of the spring) and put it all back together.
After a couple of hundred purge cycles, I got a steady IP of 125 at 3000 psi. The problem came when I checked the IP at 300 psi. It was down around 110. I opened it up, replaced the two 0.010" shims with THREE 0.015" shims (one at the base of the piston and two at the top), but that brought the IP to only 119 at 300 psi.
By the way, I did mark the HP seat cover and regulator body to ensure that the HP seat was in the same position before and after reassembly. Also, just to be sure that nothing else in the system was leaking air, I took off all hoses except for the HP hose with the SPG and the LP hose with the IP gauge (with over-pressure valve).
The Mk10 technical guide says low IP at 3000 and 300 psi is a sign of a weak spring and says one should not put more than three shims in a Mk10.
Is there any chance I have the shims arrayed incorrectly? I have seen a number of posts on this forum suggesting it is best to have at least one shim at each end of the spring (if more than one shim is needed), but the Scubapro technical literature shows all three shims in a Mk10 at the end of the spring near the knife edge.
Is my only option is to replace the piston spring? If so, where can I obtain one???