Replacing Exhaling Valve

[rstofer]

As I read the Aqua-Lung Repair Manual for the DA AquaMaster, the Exhaling Valve (item 41) can be replaced without separating the housing. Is this correct?

I started to replace the hoses and discovered that the valve has pretty much disintegrated into a gooey mess. From reading here and there, it seems this is not uncommon. I am planning to use the newer silicone valve from VDH.

Is there any particular distance to insert the valve? The instruction manual doesn't mention any particular installation depth.

Richard

 

[herman]

If it's turned to goo, you really should open the cans and clean it out. Odds are it will be very difficult to properly clean the exhaust horn without removing the can and it will be impossible to clean the internals of the cans. If the duckbill (what most of us call the exhaust valve) is goo, then the mouthpiece check valves are most likely stiff and the diaphram is likely stiff as well. My suggestion is to go ahead and order a duckbill, a diaphram, a set of mouthpiece valves and a band clamp. All are easy to replace and you will be much happier with your reg if you do. To give you an idea of what yours may look like inside, here is one I cleaned a while back. Vintage Double Hose :: View topic - Duckbill removal

How far to insert it is somewhat a matter of preference but I like the center of the opening in the duckbill to me about center of the can.

 

[Nemrod]

You have to take the cans apart and using instruments such as wooden spatulas and solvent, remove the goo. If the valve were just torn you would be able to remove it and replace without disassembly. The new silicone valves from vdh should last much longer.

The new silicone duckbills, I use a small dab of silicone to adhere the duckbill portion to the center of the top can so still, it has to come apart. This prevents the duckbill from being accidentally sucked back into the horn if the hoses get stretched or pulled.

N

 

[rstofer]

OK...

I ordered the parts from VDH. The good news with my regulator is that the mouthpiece valves are silicone. The hoses are neoprene but at least the valves are up to date.

Depending on the arrival of the Phoenix nozzles, the parts I ordered may become spares. I am just waiting for the opportunity to send this regulator to VDH for the upgrades.

Richard

 

[SwimJim]

Yes, you'll have to open the cans and remove the remains of the old one. Here's a video i made sometime back which maybe of some help. Swimjim144/Duckbill Install - Photobucket - Video and Image Hosting

Note; this video was done pre silicone duckbill days. The use of talc is no longer necessary. The approximate location of the duckbill in the video is correct.

jim

 

[Luis H]

Yes, you'll have to open the cans and remove the remains of the old one. Here's a video i made sometime back which maybe of some help. Swimjim144/Duckbill Install - Photobucket - Video and Image Hosting

Note; this video was done pre silicone duckbill days. The use of talc is no longer necessary. The approximate location of the duckbill in the video is correct.

jim

The way I tune my regulators, I need a longer duckbill than the one shown in your video. The widest part of the duckbill (where the opening slit starts) needs to be in the center of the can to reduce the chance of free flow. The free flow would be caused by having the exhaust higher than the center of the diaphragm in some positions, if the exhaust is not in the center.

All three of my Phoenix RAM are tuned to around 0.6 to 0.7 inWC, therefore the distance to the exhaust need to be less than to avoid a free flow.

Added:
For most DA Aqua Master that duckbill position would be OK, it is only for a highly tuned RAM that the exhaust position becomes more critical.

 

[Luis H]

OK...

I ordered the parts from VDH. The good news with my regulator is that the mouthpiece valves are silicone. The hoses are neoprene but at least the valves are up to date.

Depending on the arrival of the Phoenix nozzles, the parts I ordered may become spares. I am just waiting for the opportunity to send this regulator to VDH for the upgrades.

Richard

Even if you have good silicone mouthpiece valve, you may want to consider the new valve wagon wheel cages in order to improve performance. The spokes in the new cages have a cross section that looks like a diamond. This provides a very thin line for the valves to rest on the spokes.

The big disadvantage of the old wagon wheels is that the wet valves tended to stick to the spokes due to the water surface tension. With the limited instrumentation I have, I could measure a cracking effort of about 0.1 to 0.2 inWC just due to the wet valves on the original wagon wheel.

This doesn't sound like much, but at the level of performance we are looking for it adds up quickly. Also this sticking action would probably get worse with use if the valves are not perfectly clean.

Upgrading the mouthpiece valve cages is something you can do at any time. You don't need to do it now if your valves are good.

 

[duckbill]

A serrated plastic knife works great for scraping the old duckbill from the can without damaging the can. You can also use the handle of the plastic knife whenever you need to straighten out a duckbill you install while the cans are assembled (inserted into the duckbill through the horn). I keep one with my kit as it is a versatile tool which won't harm the chrome.

The original duckbills had a shoulder molded into the tubular section where it would be inverted around the outside of the horn during installation. It pretty much indexed it's own depth while you were installing it. Most DAAMS tuned to spec aren't all that picky about the position. Just get it as close to center as you can.

Watch out using solvents by your painted label.

 

[rstofer]

Even if you have good silicone mouthpiece valve, you may want to consider the new valve wagon wheel cages in order to improve performance. The spokes in the new cages have a cross section that looks like a diamond. This provides a very thin line for the valves to rest on the spokes.

I was not totally accurate when I said the mouthpiece had silicone valves. It has both the silicone valves and the new cages. At some point the previous owner had done at least that much of an upgrade. It also looks like the hoses are new. They are of heavier construction than the replacement neoprene hoses from VSS.

I'll know in a couple of days if the diaphragm has been upgraded.

But what I'm really waiting for is the Phoenix upgrade. At the moment, I'm just messing around, killing time. And waiting...

Richard

 

[DA Aquamaster]

A few years ago reproduction hoses were available from a guy in the UK. They were a bit heavier and have original looking mold marks. I have also seen heavier reproduction hoses with no mold marks.

The silicone repro hoses from vintage double hose are however great as they are a bot more flexible and perfect mouthpiece/hose/reg orientation is not required - you can be a few degrees off and it will still be comfortable.