Massive SP D350 freeflow in dive mode

[ericpitar]

Hello,

I've just pool-tested a recently serviced D350. When the dive switch is up, there's no problem. It breathes fine as far as I can tell. Pressing the purge also activates the purge as normal.

On the other hand, switching the dive switch all the way "down" causes *complete* freeflow both in and out of the water. Excuse my ignorance but is this switch designed to be only *partially* slid down when in dive mode? I can only slide the switch about 1/4 of the way down before it starts to freeflow. Sliding all the way causes complete freeflow.

Other observations. When the dive switch is slid down fully, I can see that the diaphragm assembly is retracted well towards the back to the point where the exhaust valve is visible when peeking through the sides. I also notice that at that point, the diaphragm appears to be "unreachable" when pressing the purge. I've included photos below to show the exhaust valve and diaphragm position with the dive switch up and down.

I'd appreciate the feedback.

Thanks in advance.

E

 

[Luis H]

I am looking forward to DA AquaMaster opinion on this one, but I will give you my best guess…I have limited experience with the D350 and D400 series.

It sounds to me that the little spring wire is bend out of position and perhaps in the front side of the lever.

You should be able to fully move the switch up or down without affecting the neutral position of the lever. The lever should only come in contact with the spring when you are inhaling or pushing the purge button.

The fact that you are moving the lever and diaphragm when you move the switch tells me that the spring wire attached to the switch is in the wrong position.

 

[DA Aquamaster]

The dive/pre-dive switch just moves a small spring steel arm forward in the pre-dive positon. In that position it adds a bit more spring pressure that must be over come to move the lever. In the dive position the arm moves aft and no longer contacts the lever.

My suspicion is that the spring has managed to get itself in front of the lever rather than behind it. If that were the case, placing the switch in the dive position would retract the arm and in effect pull the lever back with it.

If this occurred on a just serviced D350, I'd suspect tech error (having the switch and arm in the pre-dive position and then installing the lever behind the arm). This would also mean the tech did not test the switch for proper function.

Alternately, the lever may have been installed backwards meaning the arm and lever face different directions. That would make it much more likely for the reg to pass a bench check but then end up with the end of the arm in front of the vertical portion of the lever due to being bumped dropped or otherwise disturbed. In that case it could pass a bench check and then malfunction later. This is also understandable as SP changed the direction of the lever on the D series so it can be very confusing regarding which way a lever should face.

 

[DA Aquamaster]

Luis guess is really good.

Consistency in responses is always nice to see.

 

[Luis H]

Wow…that was quick.

 

[ericpitar]

Thank you.

1)With those possibilities in mind, any guess if storing the reg in either dive switch position would cause any damage? I don't think I can get this corrected right away so I'd appreciate some feedback.

2)How likely could either of the 2 possible causes cause permanent damage to any of the components?

3)One other observation I forgot to mention that may provide more clues is that when breathing above the water in predive mode (i.e. switch in "up" position), I could hear clicking in the casing...very similar to the sound quality when shaking the reg. (if my memory's correct, the clicking occurs in the beginnings of the inhale and exhale cycles.)

Thanks again!

 

[Isaac-1]

If the assist arm really is in front of the lever (you see considerable motion in the diaphram when moving the switch), then I would worry about keeping the switch in the pre-dive position for fear of the assist arm puncturing the diaphram. Alternatively I would be worried about leaving it in the dive postion because it will constantly be pressing lever and therefore compressing the spring. Storing half way down (or less, just enough to take pressure off the diaphram) may be best until you can get it serviced by someone that knows that they are doing.

Ike

p.s. the clicking you hear is another sign of someone not paying attention to detail when servicing a D series regulator, it is often cause by a backwards lever (set screw set so loose it shakes, but will breathe ok) or the assist arm not making contact with the lever, can also be caused by backwards lever, or bent assist arm

 

[Isaac-1]

Not meaning to hijack this thread, but on the I assume all the people that would otherwsie read it are probably reading this one theory here goes. My $58 Mk 10/ D300 off ebay just came in, both are 9-10 cosmeticly on the outside, probably need to be rebuilt though, I have only pulled the cover/diaphram off the D300 as I am at work with no tools, it shows the usual bits of corrosion on the chrome plated parts, nothing too bad, except maybe the set screw. When I get home it will be going in the ultrasonic cleaner and with some luck will be up and going shortly thereafter. My guess is this regualtor has very few dives on it, just has been in storage a LONG TIME. It certainly looks much better than my other D300, of course it has over 1,000 dives on it, and has taken its share of abuse.

Ike

 

[DA Aquamaster]

I agree the clicking lever is an issue. It could be backwards (mentioned above as a possible contributing cause of the spring issue) or it could just be really loose - which may have been an artifact of having to get the reg to not freeflow with the spring arm in front of the lever.

I would not sweat the spring compression issue - as long as it is within its working range, staying compressed for months or even years would not have a noticeable effect. The difference between compressed and uncompressed ina D350 is less than 1/8" anyway.

Likewise, if the spring arm has not poked a hole in the diaphragm by now, it probably won't.

 

[ericpitar]

Thanks all. Just an added note that yes, there is considerable movement in the diaphragm. The photos I posted show how it looks when the switch is in the full up and full down positions. The movement of the diaphragm appears proportional to the movement of the switch.