What is the lifespan of a solenoid?

***jradomski*** · 17th April 2007, 12:15

Quote: (Originally Posted by DeepBlueInnovation)

The prism solenoid is interesting in the way that the gas flow path is reversed, so that if it fails, it fails shut. To be more precise, the 02 flows into the chamber through two large orifices and pressurises the chamber in the solenoid. There is a small central orifice that is sealed by a central spring loaded seat that is drawn down when the current is activated, allowing a small measure of gas to pass through the orifice. So, if the electronics were to fail and the solenoid cease to work, it would fail in the closed position.

The prism has a seperate manual 02 addition line that can be used to maintain the P02. The only situation I can see where gas venting would be an issue is if an 02 line were to blow, and as they are made of stainless steel, this is unlikely.

As I stated earlier, I took separate bailout and undertook a dive in a controlled manner with the specific intent of identifying a problem. It was not a deep dive and it was not in the open ocean. I constantly validated my P02 and the function of my electronics.

So, with a HUD, a secondary that enables me to manually (electronics switched off) validate each cell's reading and adequate bailout, I am yet to be convinced that the process i undertook is any more dangerous than any other dive on a rebreather.

The PRISM solenoid is basically a copy of a snaptite solenoid.. The failure we are talking about can EASILY fail open.. this is not due to electronics failure but rather a mechanical failure..

ALL the Rebreather solenoids I am aware of pull open against the source pressure, so the higher the pressure (or no current flow) the solenoid is forced shut..

But what you are describing is RUST.. since the solenoid chamber has to be made of a ferous metal, so don't fool yourself.. After sitting the likely failure is to fail shut and not be able to open, but if its operating intermittingly all bets are off..
the rust particles can jam the chamber and rust flakes can prevent the orifice from sealing..

So in this case, diving manual may not be a normal option.. even if it did work, unless you totally cleaned up and lubed the solenoid, it working proves nothing and may have caused a problem on the next dive..

**DeepBlueInnovation** · 17th April 2007, 13:59

Ok, thanks for those who have replied. Here is the situation as it stands. I have stripped down, cleaned, lubed, re-assembled and performed some limited testing on the head only and so far so good. The inside of the solenoid chamber was visually clean before the process was commenced. There was a fair amount of rust on the metal chamber that houses the solenoid in the head, however this does not come in direct contact with the 02.

So, tomorrow night I will re-assemble the unit and take it for a dunk. If you haven't heard from me by Sunday - then Rick you were right

Cheers,

Ben.

**DeepBlueInnovation** · 17th April 2007, 14:08

A couple of other points to clarify, the listed problems with my unit have not occurred through neglect on my part, but rather from the previous owner being an avid cave diver, coupled with the fact that it has been sitting unused in a shed for the last couple of years. I have been cleaning, tuning and repairing the unit so that it is safe and fun to dive, not without some assistance from those who are more experienced and knowledgeable than I.

***jradomski*** · 17th April 2007, 15:11

Quote: (Originally Posted by DeepBlueInnovation)

A couple of other points to clarify, the listed problems with my unit have not occurred through neglect on my part, but rather from the previous owner being an avid cave diver, coupled with the fact that it has been sitting unused in a shed for the last couple of years. I have been cleaning, tuning and repairing the unit so that it is safe and fun to dive, not without some assistance from those who are more experienced and knowledgeable than I.

unless you know you have very dry oxygen there is not much you can do.. rust will build up over time.. If any water gets into the loop then it will just happen very quickly..

**Dave Sutton** · 17th April 2007, 17:33

Quote: (Originally Posted by silent running)

Ben, this is a very good explanation of another great Prism safety feature-all solenoids should fail closed.

Errr.... except that it's no different than any other solenoid... all of the Snaptites work the exact same way. Another "Great Safety Feature" (shared by most rigs)....

. It's not good, bad, or unique. It's just the way solenoids work.

When they corrode all solenoids can fail open.... it's just a mechanical jam. None are better than any others in this regard.

"Aviators 02" is the dry 02 choice... use it and even the cheapest solenoid will last 100 years. The difference between it and medical 02 is the guarantee of dryness (due to stratoshperic temperatures freezing the systems in aviation use). Much medical 02 is the same stuff, but Aviators 02 is *guaranteed* to be dry. Available at any gas supply place. I'm surprised that more divers don't use it: It's not measureably more expensive.

Dave

dive2dive2000 · 17th April 2007, 23:52

Hi Ben,

It might also be your depth sensor. It is hard to do a proper diagnostic through an Internet post (too many variables and what ifs). Have you spoken (by phone not email) to Sharon or Peter? I am sure they can give you a whole bunch of diagnostic protocols so you can isolate your problem. Hopefully it is the solenoid and you can replace it yourself. It sucks having to mail something to the topside

of the world for a repair. Hope it is fixed by the time you are reading this post. Just curious, do you notice a very faint blinking when your hud is green?

BTW If you do not that is a problem.

silent running · 20th April 2007, 02:46

Quote: (Originally Posted by jradomski)

The PRISM solenoid is basically a copy of a snaptite solenoid.. The failure we are talking about can EASILY fail open.. this is not due to electronics failure but rather a mechanical failure..

ALL the Rebreather solenoids I am aware of pull open against the source pressure, so the higher the pressure (or no current flow) the solenoid is forced shut..

Hi Joe, the Prism solenoid is actually the Snaptite solenoid. SMI bought the tooling from Snaptite when they discontinued the model so they could manufacture it themselves.

From what I can tell, corrosion is the first symptom of wet O2 and it's more likely to screw up solenoid operation than rust. And doesn't rust need a higher amount of moisture to form than corrosion? In the cases I've heard of with Prism solenoids failing while in normal, consistant use they've clogged up and failed closed, including mine-corrosion. Considering the very tight restrictor that's in line btw the reg and solenoid in the Prism, I think that any particle that would be big enougth to actually block it open, could only come from inside the housing itself, from flaking rust, which takes a while to form.

And then you've got the gas pressure and the force of the spring, so it seems unlikely that it would fail open without lots of water ingress or neglect. Maybe I'm missing something?

mverick · 20th April 2007, 05:43

Quote: (Originally Posted by silent running)

From what I can tell, corrosion is the first symptom of wet O2 and it's more likely to screw up solenoid operation than rust. And doesn't rust need a higher amount of moisture to form than corrosion? In the cases I've heard of with Prism solenoids failing while in normal, consistant use they've clogged up and failed closed, including mine-corrosion. Considering the very tight restrictor that's in line btw the reg and solenoid in the Prism, I think that any particle that would be big enougth to actually block it open, could only come from inside the housing itself, from flaking rust, which takes a while to form.

And then you've got the gas pressure and the force of the spring, so it seems unlikely that it would fail open without lots of water ingress or neglect. Maybe I'm missing something?

Think flash rust in a tank. Happens very quick. I don't understand your corrosion happens before rust thing. Rust is the corrosion. If you get a lot of very small rust particles they can bind together and become a little hard rock. If there is moisture it's easy to do.

All Rebreather's have this. Not just a Prism by the way.

Solenoids fail open and closed. It's just how it works. Usually if it's corrosion they fail open. Not usually all the way open but they weep. Something mechanicly blocks it from closing If it's electronic where they loose the power they fail closed.

**DeepBlueInnovation** · 20th April 2007, 06:02

Quote: (Originally Posted by Dave Sutton)

Errr.... except that it's no different than any other solenoid... all of the Snaptites work the exact same way. Another "Great Safety Feature" (shared by most rigs)....

. It's not good, bad, or unique. It's just the way solenoids work.

Hi Dave, my observations were based on the markings on the solenoid indicating the intended gas flow path was opposite of the way it is set up on my unit, so I will have to double check to make sure I haven't got it arse about - wouldn't be the first time

. Can't comment on other units operation as the Prism is the only one I am intimately familiar with*.

Cheers,

Ben.

*Not in the biblical sense as Chris used to be before his Prism divorce and ongoing affair with the Meg

**DeepBlueInnovation** · 20th April 2007, 06:16

General update: put the solenoid back together and lounge dived for a while with setpoint being maintained as expected. Took the unit down to the River for a late night test, only down to 11m for 10 minutes as that was all I had time for and I would have expected it to fail before this point previously, with setpoint once again maintained as expected. However I did receive a cell warning on one cell during ascent so any further testing will have to wait until the three cells I recently ordered arrive.

I was pleasantly surprised to receive a phone call from Sharon at SMI offering to help, and after talking through the issue she is going to organise a replacement coil.

Cheers for all the input thus far,

Ben.

17th April 2007, 12:15	#11 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,798	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by DeepBlueInnovation) The prism solenoid is interesting in the way that the gas flow path is reversed, so that if it fails, it fails shut. To be more precise, the 02 flows into the chamber through two large orifices and pressurises the chamber in the solenoid. There is a small central orifice that is sealed by a central spring loaded seat that is drawn down when the current is activated, allowing a small measure of gas to pass through the orifice. So, if the electronics were to fail and the solenoid cease to work, it would fail in the closed position. The prism has a seperate manual 02 addition line that can be used to maintain the P02. The only situation I can see where gas venting would be an issue is if an 02 line were to blow, and as they are made of stainless steel, this is unlikely. As I stated earlier, I took separate bailout and undertook a dive in a controlled manner with the specific intent of identifying a problem. It was not a deep dive and it was not in the open ocean. I constantly validated my P02 and the function of my electronics. So, with a HUD, a secondary that enables me to manually (electronics switched off) validate each cell's reading and adequate bailout, I am yet to be convinced that the process i undertook is any more dangerous than any other dive on a rebreather. The PRISM solenoid is basically a copy of a snaptite solenoid.. The failure we are talking about can EASILY fail open.. this is not due to electronics failure but rather a mechanical failure.. ALL the Rebreather solenoids I am aware of pull open against the source pressure, so the higher the pressure (or no current flow) the solenoid is forced shut.. But what you are describing is RUST.. since the solenoid chamber has to be made of a ferous metal, so don't fool yourself.. After sitting the likely failure is to fail shut and not be able to open, but if its operating intermittingly all bets are off.. the rust particles can jam the chamber and rust flakes can prevent the orifice from sealing.. So in this case, diving manual may not be a normal option.. even if it did work, unless you totally cleaned up and lubed the solenoid, it working proves nothing and may have caused a problem on the next dive.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
(Online)

17th April 2007, 13:59	#12 (permalink)
DeepBlueInnovation Prism #007 Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Sep 2005 Location: Perth, Western Australia Posts: 295	Re: What is the lifespan of a solenoid? Ok, thanks for those who have replied. Here is the situation as it stands. I have stripped down, cleaned, lubed, re-assembled and performed some limited testing on the head only and so far so good. The inside of the solenoid chamber was visually clean before the process was commenced. There was a fair amount of rust on the metal chamber that houses the solenoid in the head, however this does not come in direct contact with the 02. So, tomorrow night I will re-assemble the unit and take it for a dunk. If you haven't heard from me by Sunday - then Rick you were right Cheers, Ben.
(Online)

17th April 2007, 14:08	#13 (permalink)
DeepBlueInnovation Prism #007 Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Sep 2005 Location: Perth, Western Australia Posts: 295	Re: What is the lifespan of a solenoid? A couple of other points to clarify, the listed problems with my unit have not occurred through neglect on my part, but rather from the previous owner being an avid cave diver, coupled with the fact that it has been sitting unused in a shed for the last couple of years. I have been cleaning, tuning and repairing the unit so that it is safe and fun to dive, not without some assistance from those who are more experienced and knowledgeable than I.
(Online)

17th April 2007, 15:11	#14 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,798	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by DeepBlueInnovation) A couple of other points to clarify, the listed problems with my unit have not occurred through neglect on my part, but rather from the previous owner being an avid cave diver, coupled with the fact that it has been sitting unused in a shed for the last couple of years. I have been cleaning, tuning and repairing the unit so that it is safe and fun to dive, not without some assistance from those who are more experienced and knowledgeable than I. unless you know you have very dry oxygen there is not much you can do.. rust will build up over time.. If any water gets into the loop then it will just happen very quickly.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
(Online)

17th April 2007, 17:33	#15 (permalink)
Dave Sutton Living on Animal Farm Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,463	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by silent running) Ben, this is a very good explanation of another great Prism safety feature-all solenoids should fail closed. Errr.... except that it's no different than any other solenoid... all of the Snaptites work the exact same way. Another "Great Safety Feature" (shared by most rigs).... . It's not good, bad, or unique. It's just the way solenoids work. When they corrode all solenoids can fail open.... it's just a mechanical jam. None are better than any others in this regard. "Aviators 02" is the dry 02 choice... use it and even the cheapest solenoid will last 100 years. The difference between it and medical 02 is the guarantee of dryness (due to stratoshperic temperatures freezing the systems in aviation use). Much medical 02 is the same stuff, but Aviators 02 is guaranteed to be dry. Available at any gas supply place. I'm surprised that more divers don't use it: It's not measureably more expensive. Dave __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled. Last edited by Dave Sutton : 17th April 2007 at 17:42.
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17th April 2007, 23:52	#16 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 776	Re: What is the lifespan of a solenoid? Hi Ben, It might also be your depth sensor. It is hard to do a proper diagnostic through an Internet post (too many variables and what ifs). Have you spoken (by phone not email) to Sharon or Peter? I am sure they can give you a whole bunch of diagnostic protocols so you can isolate your problem. Hopefully it is the solenoid and you can replace it yourself. It sucks having to mail something to the topside of the world for a repair. Hope it is fixed by the time you are reading this post. Just curious, do you notice a very faint blinking when your hud is green? BTW If you do not that is a problem. __________________ Safe Diving, Martin "but what's the fun of getting what you need, instead of what you want?"
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20th April 2007, 02:46	#17 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,748	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by jradomski) The PRISM solenoid is basically a copy of a snaptite solenoid.. The failure we are talking about can EASILY fail open.. this is not due to electronics failure but rather a mechanical failure.. ALL the Rebreather solenoids I am aware of pull open against the source pressure, so the higher the pressure (or no current flow) the solenoid is forced shut.. Hi Joe, the Prism solenoid is actually the Snaptite solenoid. SMI bought the tooling from Snaptite when they discontinued the model so they could manufacture it themselves. From what I can tell, corrosion is the first symptom of wet O2 and it's more likely to screw up solenoid operation than rust. And doesn't rust need a higher amount of moisture to form than corrosion? In the cases I've heard of with Prism solenoids failing while in normal, consistant use they've clogged up and failed closed, including mine-corrosion. Considering the very tight restrictor that's in line btw the reg and solenoid in the Prism, I think that any particle that would be big enougth to actually block it open, could only come from inside the housing itself, from flaking rust, which takes a while to form. And then you've got the gas pressure and the force of the spring, so it seems unlikely that it would fail open without lots of water ingress or neglect. Maybe I'm missing something?
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20th April 2007, 05:43	#18 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 492	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by silent running) From what I can tell, corrosion is the first symptom of wet O2 and it's more likely to screw up solenoid operation than rust. And doesn't rust need a higher amount of moisture to form than corrosion? In the cases I've heard of with Prism solenoids failing while in normal, consistant use they've clogged up and failed closed, including mine-corrosion. Considering the very tight restrictor that's in line btw the reg and solenoid in the Prism, I think that any particle that would be big enougth to actually block it open, could only come from inside the housing itself, from flaking rust, which takes a while to form. And then you've got the gas pressure and the force of the spring, so it seems unlikely that it would fail open without lots of water ingress or neglect. Maybe I'm missing something? Think flash rust in a tank. Happens very quick. I don't understand your corrosion happens before rust thing. Rust is the corrosion. If you get a lot of very small rust particles they can bind together and become a little hard rock. If there is moisture it's easy to do. All Rebreather's have this. Not just a Prism by the way. Solenoids fail open and closed. It's just how it works. Usually if it's corrosion they fail open. Not usually all the way open but they weep. Something mechanicly blocks it from closing If it's electronic where they loose the power they fail closed.
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20th April 2007, 06:02	#19 (permalink)
DeepBlueInnovation Prism #007 Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Sep 2005 Location: Perth, Western Australia Posts: 295	Re: What is the lifespan of a solenoid? Quote: (Originally Posted by Dave Sutton) Errr.... except that it's no different than any other solenoid... all of the Snaptites work the exact same way. Another "Great Safety Feature" (shared by most rigs).... . It's not good, bad, or unique. It's just the way solenoids work. Hi Dave, my observations were based on the markings on the solenoid indicating the intended gas flow path was opposite of the way it is set up on my unit, so I will have to double check to make sure I haven't got it arse about - wouldn't be the first time . Can't comment on other units operation as the Prism is the only one I am intimately familiar with. Cheers, Ben. Not in the biblical sense as Chris used to be before his Prism divorce and ongoing affair with the Meg
(Online)

20th April 2007, 06:16	#20 (permalink)
DeepBlueInnovation Prism #007 Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Sep 2005 Location: Perth, Western Australia Posts: 295	Re: What is the lifespan of a solenoid? General update: put the solenoid back together and lounge dived for a while with setpoint being maintained as expected. Took the unit down to the River for a late night test, only down to 11m for 10 minutes as that was all I had time for and I would have expected it to fail before this point previously, with setpoint once again maintained as expected. However I did receive a cell warning on one cell during ascent so any further testing will have to wait until the three cells I recently ordered arrive. I was pleasantly surprised to receive a phone call from Sharon at SMI offering to help, and after talking through the issue she is going to organise a replacement coil. Cheers for all the input thus far, Ben.
(Online)

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