What could cause this problem with SP MK25?

[HNITSUJ]

I have a Scubapro MK25/S600 and MK25 R390 for my doubles. I have been having issues with the MK25/s600 intermitently having trouble delivering air. It seems my MK25/R390 delivers air better. It seemed some of the time they work fine and then sometimes under a demand, they cannot deliver. I know it is not normal as they are known to be very good (one of the better) breathers out there. I have them both in for their yearly service but was just curious as to what may cause this.

 

[Hoyden]

How recently were they serviced? Were they flow bench tested as part of the service? If so, do you have access to the flow bench numbers?

Jackie

 

[HNITSUJ]

Last year they were serviced and they are in again now. I don't have the numbers. They worked fine at first but then halfway through the season it started up. Orig. I thought it was me. But When comparing my two sets, the lesser reg breathed easier.

 

[redacted]

It's not hard to make my R190 (R380's fat father) breath easier than my G500 (old S600) by adjusting the G500 to not perform as well as it should. I suspect your S600 is also a bit more suceptable to dirt compromising performance. If the problem comes up again, we can probably put it thru some shade tree reg tech troubleshooting procedures that might help diagnose the cause.

 

[HNITSUJ]

thanks

 

[Hank49]

Can you be more specific in your statement that "it doesn't deliver"? Is it just a bit stiff? Or you're actually air starved? Just curious because I've recently converted from an MK20 to a 25. I had a new G250 on the 25 but it felt a little stiff unless I really sucked hard on it compared to the Atomic B1 that I had on the 20. I've since put the old Atomic onto the MK25.

 

[HNITSUJ]

Can you be more specific in your statement that "it doesn't deliver"? Is it just a bit stiff? Or you're actually air starved? Just curious because I've recently converted from an MK20 to a 25. I had a new G250 on the 25 but it felt a little stiff unless I really sucked hard on it compared to the Atomic B1 that I had on the 20. I've since put the old Atomic onto the MK25.

It intermittently does not deliver. Sometimes it feels fine then (usually at the worse times) will breathe hard and can't draw enough air. My other mk25 is also (as you said) a converted mk20 and that one breathes fine. Of course one of the times it really acted up was in a cave. I am not sure if I am helping you with your question. The way I see my situation, I have two identical 1st stages and two different seconds. I either have an issue with a mk25 or the s600. I would suspect if you are having issues with the g250/mk25 combo, there is something wrong because I have the cheapo R390 and it breathes fantastic. Makes me wonder why I spent the money on the S600.

 

[redacted]

For a start on troubleshooting, I'd check IP as well as IP drop when you breath and when you purge. If they were both about the same, I'd see the S600 as the primary suspect. If not, I'd be scratching my head real hard over what could cause that with the 1st stage as I prepared for a good cleaning and inspection. If the 2nd is the primary suspect, I'd check for leaks under both positive and negative pressure and then check cracking pressure and adjust as needed. Whether the adjustment did the trick or not, I'd probably go ahead and disassemble, clean and inspect. The problem being intermittent suggest to me that there may be some dirt interfering with the poppet operation or some damage to the diaphram or lever.

 

[Hank49]

It intermittently does not deliver. Sometimes it feels fine then (usually at the worse times) will breathe hard and can't draw enough air. My other mk25 is also (as you said) a converted mk20 and that one breathes fine. Of course one of the times it really acted up was in a cave. I am not sure if I am helping you with your question. The way I see my situation, I have two identical 1st stages and two different seconds. I either have an issue with a mk25 or the s600. I would suspect if you are having issues with the g250/mk25 combo, there is something wrong because I have the cheapo R390 and it breathes fantastic. Makes me wonder why I spent the money on the S600.

I think AWAP is right. If the R390 breathes OK off the same first stage all the time and you have intermittant problems with the s600, it sounds almost like something is broken and malfuntioning. If it was always stiff that's one thing but this seems to like...jam. I've never had a 600 so I've never torn one down but I'd take it back. It sounds like something is actually broken.
Thanks. I was worried that your 25 was malfuntioning. Both my 20 and 25 work fine with all my second stages. R190s, G250, B1 Atomic and a couple cheapo US diver and Seaquest octos.

 

[HNITSUJ]

I think AWAP is right. If the R390 breathes OK off the same first stage all the time and you have intermittant problems with the s600, it sounds almost like something is broken and malfuntioning. If it was always stiff that's one thing but this seems to like...jam. I've never had a 600 so I've never torn one down but I'd take it back. It sounds like something is actually broken.
Thanks. I was worried that your 25 was malfuntioning. Both my 20 and 25 work fine with all my second stages. R190s, G250, B1 Atomic and a couple cheapo US diver and Seaquest octos.

well, hold on one second. I have (2) MK25 for my doubles. I have never switched the regs around to see if the first or second stage was the problem. So in short, I have not isolated to the second stage. I really have no clue as to which is problematic