# Problem with SMS 122 pH meter



## mjhardt (Nov 12, 2009)

I am a marine biologist working out of a remote field station on the North Coast of Jamaica on some experiments that are using Milwaukee SMS122 pH Meters and the MA957 CO2 regulators to control pH in our tanks. We got 4 brand new units of the SMS 144 and the MA 957 and two of the SMS122 units are not working (the two good ones work with all regulators, so we know the regulator is not the problem). The alarm light goes on when the pH goes above the set point, but the solenoid is not turned on so no CO2 kicks in. This is a MAJOR problems and we cannot get another supply here quickly... does anyone know of a quick fix to this issue or what may be going on? Any help would be really welcomed.
Thanks so much,

Marah


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## orlando (Feb 14, 2007)

Sounds like a bad solenoid? If you can, try taking the solenoid apart and reassemble


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## mjhardt (Nov 12, 2009)

Hi there,

It is not the solenoid, which is part of the co2 regulator (C). We know this because the regulator works with a different SMS122 pH meter. I think it is either in the relay from the pH meter to the big black box that the solenoid connects into, or it is in the black box itself. There doesn't seem to be any way to disassemble this part...


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## freshyleif (Jan 9, 2008)

When I first got my PH controller it did that after the first water change but I unplugged it and then re calibrated it and the problem went away. If that does not work than I would agree that the black box is probably where the problem is but would check the plug in connection for the solenoid maybe it is loose or not making a proper connect.


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## ianryeng (Dec 22, 2008)

Do you have any way to check the solenoids? I can't find any specific information on them on Milwaukee's site but based on the description of the controller you are using I would be lead to believe that they are 12VDC coils. If this is true you should be able to connect them directly to a DC supply (a 9v battery may be enough even) to at least establish the the solenoid works, the solenoid should have a rating on it as to its power source. 

To check that the controller works you could use a multimeter to verify that the controller is supplying voltage (or any change of state for that matter) when it enters an alarm state.

I sincerely hope you find a solution to your problem. From my experience nothing is ever as easy as it should be.


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