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EHowe
Master Diver
Posts: 200
Joined: Sun Aug 28, 2011 2:59 pm
First Name: Edward
Location: Chicago

DBE induced freeflow

Tue Jul 28, 2015 3:45 pm

Today when checking my DAAM I found a slight freeflow. I originally rebuilt this reg as an original with duckbill and c-clips. When started this project the cans were dented up pretty good and I strightened as best I could and it's been a great reg altough it looked a little used. This year I added a Cyclone, DBE and band clamp and it's now my goto reg for my doubles. My first check was the IP and found it to be around 145 psi.I backed it off 5-10 psi cycled it a bunch and all seemed good. Reinstalled cans and hoses, put it on a tank -freeflow. When I loosened band clamp freeflow stopped :? . tighened it stared again. I took my stanley knife and trimmed down the little plastic lip at the end of the DBE just before the valve. Problem seems solved. I think these cans are probobly still a little out of wack and the lip of DBE was applying pressue to diaphragm when tightened.

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Bryan
Plank Owner
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Joined: Fri Jun 24, 2005 11:40 am
First Name: Bryan
Location: Wesley Chapel Florida
Contact: Website

Re: DBE induced freeflow

Tue Jul 28, 2015 5:52 pm

Happens quite often with circle label cans. Mostly due to the center of the can being lower than their predecessors were. Also they seem thinner and more prone to distortion. I've never run across a square label can where trimming the DBE was necessary.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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luis
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Joined: Thu Jun 30, 2005 9:28 pm
First Name: Luis
Location: Maine

Re: DBE induced freeflow

Tue Jul 28, 2015 11:00 pm

Just be careful you don’t cut too much of the plastic stop. The plastic stop is needed to prevent the diaphragm from blocking the exhaust valve.

If you already cut too much, you are going to want to replace it. Check that the valve has good clearance when you exhale.

If needed you can adjust the lever a bit lower. If you are using a new super flexible silicone diaphragm, the lever height is not as critical. This is particularly true if you are using an HPR and a new diaphragm without the tabs.

If you have not upgraded to the HPR, I recommend that you do. If this is a regulator you dive often, you will notice a performance improvement and many advantages (not needing to align tabs, easier to adjust, etc.).
Luis

Buceador con escafandra autónoma clásica.

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EHowe
Master Diver
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Joined: Sun Aug 28, 2011 2:59 pm
First Name: Edward
Location: Chicago

Re: DBE induced freeflow

Wed Jul 29, 2015 9:02 am

Thanks for the input guys. It is a square lable can and seems to be working good. I figured there was a reason for that stop so I didn't go crazy on it. Am I correct to assume that the clearance between valve and diaphragm increase at depth? If that's the case it probably would not have been a problem once it was in the water. There probably is an HPR in the future for this reg. I have one in my Phoenix now .

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luis
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Location: Maine

Re: DBE induced freeflow

Wed Jul 29, 2015 9:28 am

EHowe wrote:Thanks for the input guys. It is a square lable can and seems to be working good. I figured there was a reason for that stop so I didn't go crazy on it. Am I correct to assume that the clearance between valve and diaphragm increase at depth? If that's the case it probably would not have been a problem once it was in the water. There probably is an HPR in the future for this reg. I have one in my Phoenix now .
No, it doesn't.

The pressure differential should always be the same. The diaphragm and lever height will always return to the same position after every inhalation. It is a pressure compensated system. The increase in pressure is balanced inside and out.
Luis

Buceador con escafandra autónoma clásica.

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Bronze06
Master Diver
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Joined: Tue Jul 01, 2014 5:33 am
First Name: Russell
Location: Tabuk, Saudi Arabia

Re: DBE induced freeflow

Thu Aug 13, 2015 7:18 am

Luis Rocks!!!! :!: I've rebuilt 20 regs so far and in 75% I use the DBE. I had good cans though on my 1973 RAM and have experienced no problems with the DBE on it. It has to be a round can issue though as Bryan stated, but I didn't run into this problem on the 1973. Great information from the Luis Meister.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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