Help with Sherwood Magnum Reg

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Waterskier1

Contributor
Scuba Instructor
Divemaster
Messages
868
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8
Location
Colorado Springs, CO
# of dives
200 - 499
I took my Sherwood Magnum Regulators to my LDS for servicing before I left for 5 weeks of diving throughout the Caribbean. There was nothing wrong with them, but they hadn’t been serviced in just over 2 years (around 200 dives) and I didn’t want any problems on my dive trip.

I have 4 Sherwood Magnum 1st and 2nd stages. I have two for my doubles, one for a pony bottle, and the last is for a stage or backup. I put two second stages (one my normal primary, and the other my pony bottle) on my primary first stage so that I could get two 2nd stages along with one 1st stage serviced. When I got them back, I checked them in the LDS’s pool, and all seemed fine.

I reconfigured the 2nd stages, putting the pony 2nd back on the pony 1st, and I put my other (second post regulator) 2nd stage on as an “octo” for this trip, since I wouldn’t be diving doubles. This second post regulator was less than 2 years old (as far as use goes – I bought it as New Old Stock).

Well, on my trip, my main 2nd stage became very difficult to breath, especially below 50-ft. I have the inline adjusting tool, and adjusted the cracking point to where is would almost free-flow. Even with this adjustment, the unserviced 2nd stage (from my second post regs) breathed much better. Even while holding in the purge valve on the serviced 2nd stage was still difficult to breath. It was also breathing wet. I lived with this condition since the water was warm, the visibility was great, and I wasn’t doing any challenging diving (nothing over 100-ft, no wrecks, no deco, etc.).

When I returned, I took the regs back to the LDS, where the owner told me they were very old design, and were not performance regs. I agreed they were older design, but the problem was with one 2nd stage since it worked fine before servicing, and the other (not serviced) 2nd stage worked fine under the conditions I dove. I suggested that maybe something other than what was in the service parts kit might be going bad (maybe a diaphragm or seat). He said he would have his repair tech look at it.

Well, I got a call from the repair tech stating that he took it apart, looked at it, and didn’t find anything wrong, and put it back together. I asked if it met the spec’s when tested. He said they don’t have test equipment to test! I asked about a magnehelic and was told he didn’t have one. When I picked up my reg set today, I was charged for another service job. But, by the tech’s own admission, he found nothing. The shop salesman told me it was serviced and adjusted. When I questioned him on the “adjustment” portion, since the tech told me he didn’t have any equipment to objectively measure, I was told all that was necessary was to put it under water.

While I understand that placing a reg underwater, can indicate free-flow potential, I didn’t think it was the accepted method of adjusting cracking pressure and inhalation effort.

I asked why I was charged if the tech didn’t do anything, and was told that the tech charged them (the LDS) so they had to charge me. The manager and owner of this LDS are both out of town, so I couldn’t discuss this with them. Also, I’ll have to drive several hundred miles to find a location where I can dive deep enough safely this time of year, to determine if there is any change.

So, what do you guys think? Is this tech’s procedure acceptable given that he knew that one 2nd stage (which worked fine before his service) was considerably different (inhalation effort and wet breathing) than an identical (except not serviced by him) 2nd stage, both connected to the same 1st stage?

I know that the usual place to look for “at depth” problems is the 1st stage (is it maintaining IP at depth) but since another identical 2nd functioned fine at depth, I ruled out the 1st stage. Also, I still believe that the wet breathing may somehow be connected.

Lastly, to whom would you suggest that I send this reg to for repair? It seems clear that I expect more than a “take it apart, replace some o-rings, look at it, put it together, and charge the customer effort.
 
I used to use a sink full of water to measure and adjust cracking pressure, but I am not a '"professional" and only service my own reg. I feel the method is adequate but even I broke down and spent $20 on a magnehelic gauge. It's hard to imagine a professional shop without one (and an ultrasonic cleaner).

Based on the symptoms you describe, I'd be looking for a seal on the reg body that was failing to seal the water out adequately. This would produce wet breathing and increase WOB as part of the breathing work is pulling in water. First do a vacuum test. I suspect it will leak. Then you might try drying the reg real good inside and then sealing the mouthpiece and submerge it for a while to see if it takes on water. If it does, I'd expect a free repair and a refund of the 2nd charge.

Then find another shop.
 
I don't think the problem is with the 2nd stage.
There was a bunch of Sherwood regs in the early/mid 90's that had problems with the balancing (cupped) washers cracking.
I had one of these regs. I could make it breathe great at the surface but it breathed terrible below about 60'.
 
And people wonder why so many of us do our own work.
There is no excuse at all for a "repair shop" to not have a magnehelic gauge, that is your first clue they have not idea what they are doing. Most likely "putting it underwater" refers to what many of us call the sink test, basically you submerge the second stage with the mouthpiece up and see where it starts to flow. The distance from the diaphram to the water line is equal to the cracking pressure in inches. Absolutely no excuse for a shop using this as an after service test but it is useful at home or on the dive test, just to see if things look reasonable.
From the discription you give, I would look for either a seal leak and/or a misadjusted lever. With a poorly adjusted lever, the extra effort needed to inhale may have caused you to pull water past the exhaust valves.

And either find another repair center or learn to do it yourself.
 
I don't think the problem is with the 2nd stage.
There was a bunch of Sherwood regs in the early/mid 90's that had problems with the balancing (cupped) washers cracking.
I had one of these regs. I could make it breathe great at the surface but it breathed terrible below about 60'.

While that may be a problem with some, I have personally had this same regulator to below 150-ft over 10 times, and didn't notice a significant breathing problem, and no wet breathing.
 
And people wonder why so many of us do our own work.
There is no excuse at all for a "repair shop" to not have a magnehelic gauge, that is your first clue they have not idea what they are doing. Most likely "putting it underwater" refers to what many of us call the sink test, basically you submerge the second stage with the mouthpiece up and see where it starts to flow. The distance from the diaphram to the water line is equal to the cracking pressure in inches. Absolutely no excuse for a shop using this as an after service test but it is useful at home or on the dive test, just to see if things look reasonable.
From the discription you give, I would look for either a seal leak and/or a misadjusted lever. With a poorly adjusted lever, the extra effort needed to inhale may have caused you to pull water past the exhaust valves.

I am aware of this "field test" for cracking pressure. And, I agree it is a good "field test", but should not be the definitive test AFTER a reg is brought back for hard breathing/wet breathing, IMHO.
 
And people wonder why so many of us do our own work.


And either find another repair center or learn to do it yourself.

Frogkick.dk has manuals for all sherwoods.

I have the manuals (from them), and have replaced the items in the service kit on my backup reg. I have several service kits.

Unfortunately (or not?) the other LDS in town, where I'll take my tech classes, doesn't allow people to work on their own regs if they are doing tech diving, and requires a receipt of reg service within 1 year to take their sponsored classes. I say sponsored, because they aren't a tech shop, and don't have the tech instructor, but bring in a TDI instructor from out of town. I plan on taking a couple of these courses, so that's the main reason I took in the regs. I didn't take them to that LDS because on every trip or pool session with that LDS, someone has had reg problems, and they are not an authorized Sherwood service center. Also, I felt they implemented that rule just to get additional business.

I have no problems following the service manuals (not near as difficult as overhauling a 4-barrel carb) but knew I didn't have experience or training if something didn't work right (like hard breathing).

So, now I'm looking for a reputable shop - I've been told there is a shop on the east coast that does nothing but work on regulators, and gives you print-outs of the condition upon receipt and after their work. But, I don't remember the name. So, I'm hoping some of you might suggest a shop that you know does good work, including troubleshooting reg problems, and not just replacing o-rings and dropping it in the water.
 
From the discription you give, I would look for either a seal leak and/or a misadjusted lever. With a poorly adjusted lever, the extra effort needed to inhale may have caused you to pull water past the exhaust valves.

I'm guessing this might be it. From what I've read in the Sherwood manuals, after adjusting the orifice to just stop free flow (hiss past the second stage orifice) you are to check the relationship between the diaphragm and the tip of the lever assembly using the Sherwood lever height gauge and adjusting tool. I admit I don't know regs well enough to know if this makes a difference, but the shop who did mine says they never make this adjustment since it should never change. It's also a "bend to adjust" type of adjustment, and they may not want to take the chance of breaking something or really screwing something up that can't be corrected by simply unscrewing.

I can't find anything in the Sherwood manuals that address "cracking pressure" versus "inhalation resistance" as far as adjustments are concerned. I can find both specs listed, so I assume that both can be made to be in compliance, even if it might be a replacement part versus an adjustment.
 
This may be the shop you are talking about. http://www.airtechscubaservices.com/ In any case, these guys are first rate and one of the largest repair only facilites on the east coast. They are local to me and I know all of the techs, all of which are great guys. If I have to take a reg in, this is where it goes and it is the place where the local shops send their problem regs.
 
https://www.shearwater.com/products/peregrine/

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