Mares Abyss 42 Pressures

[ferris213]

Hi,

I posted this in the Mares forum but haven't got a response, so I thought I might try here for a bit more exposure...

Could someone please tell me the recommended IP for the Mares 42 first stage? As well as the recommended cracking pressures for an Abyss second stage (primary) and Rover second stage (occy)?

Ideally I would like to know the factory specifications, but any help would be greatly appreciated.

Thanks.

 

[LeadTurn_SD]

Hi ferris213,

I do not have the factory spec for the MR-42. I do have it for my MR-22's and MR-12's, and do believe the IP spec will be identical.

142 - 148 psi should be the correct IP range for your first stage, this is the factory spec for most of the Mares diaphragm regs.

The IP can be set a bit lower and still provide plenty of air (135 psi for example); but most of my Mares 1st stages (I have six) seem to "want" to lockup at about 140-145 psi. Anything from 130 - 148 should be "ok" as long as it is a solid "lockup". There should be no creep.

You will tune your 2nd stages to whatever IP you are running your 1st stage at.

I tune my Mares Abyss 2nds to about 1.1 - 1.2"... this is a little "hotter" than they often come from the factory, and will make them prone to freeflow if they are handled carelessly on the surface or underwater (which is true for any high performance 2nd stage that is properly tuned), but they should be perfectly stable at this cracking pressure.

I do not have a Rover 2nd stage, but would probably tune it about the same as my Rebel 2nd stages (used as octo's).... a very slight de-tune (compared to the Abyss), about 1.4 - 1.5 " cracking pressure. Again, they will be slightly "fussy" on the surface (prone to freeflow if mishandled), but stable underwater, and will breath well. I don't like to de-tune my backup 2nd's (octo's) more than this.

Greg Barlow is a great resource for all things Mares, and if he sees this thread will probably have more specific or better advice.

Best wishes.

 

[ferris213]

Awesome, thanks so much.

I got mine serviced, but wasn't too happy with how they breathed. Took them to a different shop and found out the Occy was set to 1.8" and the Primary was set to 2.2"!!! 1st stage was set to 138-140psi

Thanks again.

 

[Shcubasteve]

...142 - 148 psi should be the correct IP range for your first stage, this is the factory spec for most of the Mares diaphragm regs...

You are correct, 142-148psi @2900 from the service manual- that is unless you have a cold water kit- 133-139 would be the correct setting.

For a Mares' primary, 1-1.3" of water should open the demand valve- 1.2-1.4" for an Octo. OP, if your not working with a mares Lab authorized repair facility, they might not have correctly set the orifice (seat connector) to its preliminary setting.

 

[Greg Barlow]

Hi ferris213,

I do not have the factory spec for the MR-42. I do have it for my MR-22's and MR-12's, and do believe the IP spec will be identical.

142 - 148 psi should be the correct IP range for your first stage, this is the factory spec for most of the Mares diaphragm regs.

The IP can be set a bit lower and still provide plenty of air (135 psi for example); but most of my Mares 1st stages (I have six) seem to "want" to lockup at about 140-145 psi. Anything from 130 - 148 should be "ok" as long as it is a solid "lockup". There should be no creep.

You will tune your 2nd stages to whatever IP you are running your 1st stage at.

I tune my Mares Abyss 2nds to about 1.1 - 1.2"... this is a little "hotter" than they often come from the factory, and will make them prone to freeflow if they are handled carelessly on the surface or underwater (which is true for any high performance 2nd stage that is properly tuned), but they should be perfectly stable at this cracking pressure.

I do not have a Rover 2nd stage, but would probably tune it about the same as my Rebel 2nd stages (used as octo's).... a very slight de-tune (compared to the Abyss), about 1.4 - 1.5 " cracking pressure. Again, they will be slightly "fussy" on the surface (prone to freeflow if mishandled), but stable underwater, and will breath well. I don't like to de-tune my backup 2nd's (octo's) more than this.

Greg Barlow is a great resource for all things Mares, and if he sees this thread will probably have more specific or better advice.

Best wishes.

Lead Turn

Lead Turn has some great advice, and I concur with his recommendations. I have gotten to the point where I set the IP to an even 140psi on all the Mares diaprhagm models. It makes it simple for me to monitor the stability of the IP while I am at dive sites. I really don't think that increasing the IP to the higher end of the range makes an appreciable difference.

My recommnedations on tuning the various second stages is to set the primary to 1.2", and the back-up to 1.4". On my own personal regs, I set the primary to 1.0" on the Proton models, and 1.2" on the larger bodied units. The case geometry fault of the Proton permits the slightly lower cracking effort. I maintain the 1.4" on the back-up, as I wear mine around my neck, and want to make certain that they don't leak no matter the orientation of the mouthpiece.

Greg Barlow

 

[ferris213]

Thanks everyone.

I had my regs tuned by a different shop and they have been set to the pressures you have recommended. (octos might be a little bit higher at 1.6")

I just need to dive them now....