Can you Unbalance a Scubapro MK25?

[divingtactics]

I have a rebreather application that would suit the MK25 but the regulator can't be a balanced design due to the solenoid design and higher battery use at higher IP's. Does anyone know if there is a part I can modify or remove to unbalance one of these.

There are other unbalanced designs out there and other brands, but I have heaps of these lying around and like the hose routing for this application.

If all else fails, I'll just buy some TEK3 Apeks and remove the Hydrophobic Membrane and Transmitter.

 

[redacted]

The design is inherently balanced.

 

[divingtactics]

Ok, thanks AWAP. Tek 3's it is then.

 

[halocline]

High or low IP has nothing to do with balanced, if that's relevant here. In fact, the MK25 would be an ideal 1st stage to run at a low IP because it has such a high flow rate. You could easily adjust it to 120PSI or lower, I suspect. I'm not sure if that's helpful to you or not.

An unbalanced 1st stage will have a much wider range of IP through the supply pressure, starting high and ending low....that's assuming you get an unbalanced piston first stage, which I believe is the only type available these days.

 

[Kunundrum]

I think you are confusing Balanced with depth compensated.

I think what you mean to ask is can you remove the depth compensation off a MK20/25 and the answer is yes you can, you have to plug (and seal) the ambient chamber of the regulator. this stop the water pressure from pushing down on the piston and driving up I.P. at depth.

I am in the process of doing the same thing to a MK20UL to drop a little weight off my Sport Kiss (Vs the DS4 on there now).

IF you do go with TEK3 a blanking plate is best to remove depth compensation off a sealed diaphragm regulator.

Added:

Also keep in mind that whatever I.P. you set the regulator to will influence the maximum depth where the regulator will operate IE: 120psi = 8.1AT = 238' meaning that the 1st stage will stop flowing gas past 238' depth.

 

[axxel57]

Divetactics, I'm not a Rebreather Specialist, but I guess you got something wrong.
Whatever you want to do with a TEK3, you can do also with a MK25 and safe the money for this investment if you've got already the MK25. The TEK3 is a (over)balanced Diaphram Type 1st stage. the MK25 a Piston Type. I would'nt know what could make a difference in the function of the rebreather.
As Halocline wrote is the IP of ballanced or nonballanced types of 1st stages generally about the same, in unballanced types just not as stable over the dive when normal scuba tanks are getting more empty.
Why a stable IP throughout the dive could be a problem in rebreather applications when you can adjust the IP up to a certain extend I don't understand, but if so, you can use the MK25 the same way as the TEK3. Good luck.

 

[elan]

Kunundrum summed it up. The OP uses balancing in place of depth compensating. Kunundum, how are you planning to plug the holes on yor MK20 ? Even if you simply plug the holes somehow you still need to install an o-ring between the cap and the body as that connection is not sealed. I guess MK10 will work better for this application if you manage to close the holes with ay a rubber band and a metal ring as it has an oring between the body and the cap.

 

[DepthCharge]

Don't take offense but should you be messing with a RB? Solenoids work by pressure differential, not absolute pressure. Depending on the solenoid, would dictate the pressure you need to set your reg at. Some are <100psi and some are greater. No need to have a non-depth compensated reg.
Later,
John

 

[Kunundrum]

I have an old brass MK20 cap that I have plugged the holes with a high strength epoxy, and use of an O-ring on the cap to seal of the chamber. (one from an MK19 fits quite nicely), I'm just finishing up some cleanup on the cap now and will test it on cylinder at depth on a dive next weekend, and see if it works and the I.P. stays constant.

 

[elan]

I have an old brass MK20 cap that I have plugged the holes with a high strength epoxy, and use of an O-ring on the cap to seal of the chamber. (one from an MK19 fits quite nicely), I'm just finishing up some cleanup on the cap now and will test it on cylinder at depth on a dive next weekend, and see if it works and the I.P. stays constant.

Got you, please let us know how it works!