Trailermann Posted February 2, 2018 Share Posted February 2, 2018 I have been going nuts trying to adjust my bubble count with the Milwaukee MA 957 CO2 regulator. I set the needle valve for a nice even bubble flow, and then later, I have to open it up more for the same flow. This went on several weeks as I tried to adjust the effluent flow, the primary and secondary CO2 pressure gauges, and whatever else I could fiddle with, hoping to get a steady bubble flow. Finally I saw mention of a clogged needle valve and found this instruction: MA957 Clogged Needle Valve Repair Procedure Over time dirty CO2 gas flowing through the regulator will start to deposit dust and dirt in the small gas line located inside the needle valve. When these deposits become large enough the gas flow becomes restricted and eventually will stop. When you add more gas pressure, forcing the gas pass the inline restriction, the flow will start back but as the backpressure subsides the gas flow and bubble count will also diminish and will again eventually stop. This yo-yo effect causes the operator to apply even more pressure from the large black main regulator knob (Macro adjustment) until the backpressure is so high that the solenoid will not close, even when power to the solenoid is turned off. This high backpressure in the solenoid piston chamber will allow gas to continue to flow through the regulator dropping the pH to 5.5 causing a catastrophic effect on all biological life in a tank. Field repair procedure - Turn the tank off and take the regulator off the tank. Take the bubble counter off the regulator needle valve. Open the needle valve all the way open by turning the knob counter-clockwise until it stops. Use a 1/16” drill and go through the top hole of the needle valve and drill through the base of that hole until you feel the drill pass through into the main chamber. Drill time is only about 2 seconds at full drill speed. Turn the regulator over and tap the needle valve on a table to knock out the drill filings. Remount the regulator. Note: If 1/16” drill is not available then go to next size which is a 5/64” drill bit. Eureka, I found the problem. So I drilled out the valve and reassembled. ......Started out fine, but after a short honeymoon, it again slowly shut off the flow of gas. So either I did the procedure wrong, or something else is wrong. OK, next solution -- install the highly touted CarbonDoser. Should solve my problems, right? Not!!! The used unit I bought for $250 did not work. No gas flow. So I put it into a box and sent it into AquariumPlant.com for repair. Back to manual daily two part dosing. Crapola, solving our country's immigration challenge would be easier than this. FYI, I already know the answer to that problem. Quote Link to comment Share on other sites More sharing options...
albertareef Posted February 2, 2018 Share Posted February 2, 2018 Sorry to hear you are having such a struggle with this Paul. This kind of experience is why I have defaulted to strictly pH control over my reactor - no fine control valves for either the CO2 or the effluent lines as they simply clog and/or drift way too often in my experience. Solenoids are simple - on or off - and seem to have far less issues with variability. Hope the repaired carbon doser regulator works out for you - I know a lot of people here have reported success with those. Quote Link to comment Share on other sites More sharing options...
Trailermann Posted February 2, 2018 Author Share Posted February 2, 2018 Thanks for the suggestion. It never occurred to me to bypass the needle valve and bubble counter. Can you suggest a fitting to screw into the solenoid with a push-to-fit or slip-on end for the tubing? Quote Link to comment Share on other sites More sharing options...
albertareef Posted February 2, 2018 Share Posted February 2, 2018 3 minutes ago, Trailermann said: Thanks for the suggestion. It never occurred to me to bypass the needle valve and bubble counter. Can you suggest a fitting to screw into the solenoid with a push-to-fit or slip-on end for the tubing? Hmm. I'm not the best with fittings. My solenoid in incorporated into the regulator prior to the CO2 port so not really any opportunity for separate connections. Maybe a pic would help to see what you are working with? Also - just to help clarify, I don't really bypass the bubble counter so much as run a higher flow rate (1-2 per second) where fluctuations won't really come into play and the valve on the regulator is far less prone to clogging. My effluent is around 80 - 100 mls/min I think (don't have a flow meter on it but might consider that in the future - Bicyclebill uses one that is pretty simple) so, likewise, high enough to avoid issues with needle valves. Hope this helps. Somewhere, @Bicyclebill had a nice write-up of this approach but not sure where it is anymore. I basically stole it from him after getting frustrated with trying to do fine control on both effluent and bubble rate and the challenge of two variables in combination with really finicky hardware. Quote Link to comment Share on other sites More sharing options...
Trailermann Posted February 2, 2018 Author Share Posted February 2, 2018 Let's see if these zipped photos are view able. Quote Link to comment Share on other sites More sharing options...
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