Service manual for mares 28 xr and HR

[lowwall]

Do you still adjust the IP with the part to the lower left of the part with the 4 holes? How do you set the CWD body and cap to keep from messing up your IP setting?

 

[BjornS]

Do you still adjust the IP with the part to the lower left of the part with the 4 holes? How do you set the CWD body and cap to keep from messing up your IP setting?

The ajustment nut is threded in the cwd/piston body. See red markings on picture. When everything except cap of cwd kit is asembeld, regulator is conected to a full scuba tank and ip is adjusted with 10mm allenkey. When ip is stable on 10 bar the second or top part of the dual piston (see picture with green marking) is inserted from top side of the firststage (still presurized) and then the cap. Ip is not messed up if regulator is presurized under this part of asembley and cap is just snug not excessivley thigthend.

 

[lowwall]

The ajustment nut is threded in the cwd/piston body. See red markings on picture. When everything except cap of cwd kit is asembeld, regulator is conected to a full scuba tank and ip is adjusted with 10mm allenkey. When ip is stable on 10 bar the second or top part of the dual piston (see picture with green marking) is inserted from top side of the firststage (still presurized) and then the cap. Ip is not messed up if regulator is presurized under this part of asembley and cap is just snug not excessivley thigthend.

Thanks. I think I can see how it all works now.

Except did they really remove the pin that normally goes through everything from the button poppet to the HP chamber?

 

[BjornS]

Thanks. I think I can see how it all works now.

Except did they really remove the pin that normally goes through everything from the button poppet to the HP chamber?

No, the pin don’t show on picture. Same pin as on the mr52

 

[Alurpal]

I use the 28xr as my single tank back mount first stage. I’ve reviewed the differences between diaphragm and piston regulators and thought I understood but can someone explain to me how this “diaphragm” regulator functions without a diaphragm? Or am I fundamentally misunderstanding something?

 

[lowwall]

The two jobs of the main diaphragm in a diaphragm reg is to seal off anything from getting into the air chambers in the reg and to transmit the pressure from the main spring (aka diaphragm spring) and ambient water pressure to the pin that opens the valve.

It looks like Mares has - for the regs using this coldwater kit - replaced the rubber diaphragm with a metal disk with an o-ring. The disk with o-ring performs the sealing function and directly transmits the main spring force. The stem on the disk and the other piston serve to keep everything aligned and to transmit the ambient water pressure to the disk with o-ring.

(I recommend turning down the sound before clicking.)

These two piston-shaped parts have nothing to do with the piston in a piston regulator. In a piston regulator, the piston doesn't just transmit pressure to the valve, it is the valve. It is also the pathway for gas to flow from the HP to intermediate pressure sections of the reg.

 

[uw-systems]

Nice picture. It is very interesting that the new dry kit (Twin Balanced Piston) does away with the primary diaphragm.

Here's a couple of other images for comparison:

82X (no coldwater kit)

22 Extreme (old dry cold water kit)

Do you have the Mares Service Manual / Parts Guides (Vol2-2020ed) or newer this screen shot is from?
I have a 28X + Adj 2nds (99% & the same as the 28XR) and it looks like the 1st major 1st stage change in 20+ years. Although the same concepts... Just a inverted piston subing for diaphram. Not the old school high flow piston with the seat seals on the piston stem. The IP seems to be higher (148 psi) and other changes to the 2nd stage mechanics. The 82X is more of a sealed diaphragm design but almost the same stack as a 28XR, sans the psudo piston.

PM/DM if you can. Cheers.

 

[lowwall]

Do you have the Mares Service Manual / Parts Guides (Vol2-2020ed) or newer this screen shot is from?

No I don't have anything that recent. Someone posted this image on another thread and I grabbed it.

I wish I did. After a couple of decades of variations on basically the same 3 first stages (12, 22, and 2) and 3 seconds (Abyss, Proton, Rover/Prestige), Mares appears to have made some actual advances to their lineup.

 

[Noam Katsir]

Hi
Did anyone have any progress with getting a 2022 service manual?

 

[Zef]

Hi
Did anyone have any progress with getting a 2022 service manual?

לא, סליחה. כרגע יש לנו רק דיאגרמות

-Z