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[APD] Fun with CO2 regulators

Since CO2 regulation has been a topic (AGAIN?) lately. I thought I'd
mention my latest mishap.

Last week, my CO2 regulator bit the dust. I walked by and noticed I was
going to need a fresh CO2 bottle since I was down to about 600 PSI on
the high side, I also noticed that my "low" pressure side was about 1/4
revolution past the red zone on the gauge. Yikes! Fortunately, this is a
really low pressure setup and the end of the red zone is only 15 PSI. It
didn't get high enough to blow the pop off valve, or the gauge. Based on
my limited sample of 3, it seems I am only getting about 5 years out of
each regulator. I hope others are more fortunate.

Sadly, more fun was to come. Once I tried to dial back the pressure on
the low side, I realized that I couldn't get the low side to quit
flowing when the solenoid was open. It dropped to 2 PSI and continued
flowing at that rate with the regulator screw fully loosened. If I let
the solenoid close, the low pressure PSI would climb until the gauge
pegged. It looks like both the diaphragm and the high pressure switch
were leaking. 

The good news is that the combination of a needle valve and pH
controller driven solenoid prevented the regulator failure from driving
the pH down in the tank. At that pressure, it was flowing a LOT of CO2
when the solenoid opened. Even though the pressure increased from my
usual 5 PSI to "something over 15 PSI and under the 50 PSI pop off", the
tank was in no danger (unless the gauges exploded and shattered the

BTW: This has pretty much been my experience with CO2 end of bottle
dumps, as well. The low side pressure climbs, the CO2 flow rate
increases, but the needle valve prevents really absurd CO2 flow rates
and the pH controller cuts off the flow when the pH drops. It is "no big
deal" on my tank, but your mileage may vary on smaller tanks.

The folks M3 overnighted me one of their latest CO2
regulator/solenoid/needle valve combos. It is working very well. My old
Uniweld regulator looks to be rebuildable. At least next time, I'll have
a spare regulator:)

Jon Wilson

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