Prime Water LimitedTelephone: 44 (0)1206 512234 . E-mail: |
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Kowa On-Line Nitrate Monitor
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Symptom |
Possible Cause and cure |
| Occasionally WARN 12 or WARN 14 shown on the display. | Sample flow rate too high causing gas bubbles to come out of solution. Reduce the flow rate using the flow control valve on the front panel. |
| "ERR 6" displayed when scrolling through the parameters. | Incorrect calibration caused by leaky flow control valve. Replace th flow control valve and recalibrate. A temporary solution is to turn the flow off elsewhere and then recalibrate. |
| Readings lower than expected. | Inlet solenoid valve leaking causing the instrument to auto-zero on a blend of de-ionised water and sample water. (This only applies to older instruments with brass bodied inlet solenoid valves.) All readings are then reduced by the amount of nitrate in the blend. Replace the inlet solenoid valve (or just the brass body) and activate a manual rinse. |
| Re-calibration isn't accurate (1). |
The connections to the dilute acid and de-ionised water bottles have been swapped, resulting in the instrument autozeroing on dilute acid. Replace the tubes in the correct containers, give the instrument a manual rinse and recalibrate it. |
| Re-calibration isn't accurate (2). | The standard solutions have been contaminated. Replace the solutions and recalibrate. |
| "ERR 2" displayed (1). | Loose sediment is being washed through the measurement cell blocking the light path completely. Flush the sediment out of the instrument and cancel the ERR. |
| "ERR 2" displayed (2). | The flash tube has failed. This is extremely rare. In a quiet environment the lamp can be heard ticking as it flashes. Call out the engineer for an exchange optical assembly to be fitted. |
A monitor was showing exceptionally high readings for one hour per day. It was located on the outlet of a reservoir which was supplied from two different water sources, one with high nitrates the other with low nitrates. It transpired that the pump for the high nitrate source was being switched on an hour before the low nitrate pump, resulting in a stream of high nitrate water flowing straight across the reservoir to the outlet. Only when the low nitrate pump came on was the high nitrate stream mixed with the rest of the water in the reservoir. The monitor was measuring accurately and brought the pump problem to light.
A customer complained that his instrument would display ERR 2 , indicating a lamp failure, at irregular intervals. When he cancelled the ERROR it would continue to run properly for a while before again showing the ERR 2 message. The problem was traced to the very high iron content of the water which was being monitored. The inlet tube had become encrusted with rust deposit and occasionally a piece of rust would come adrift and temporarily block the light in the measuring cell.
The electronics associated with the high voltage flash unit of an instrument had broken down. On examination, the circuit board had mould growing on it and this had upset the operation of the circuit. The cause of the mould was the large mains water pipe located above the instrument. On a humid summer's day, the instrument was perpetually being rained on with condensation from the pipe.
If you have a problem with a Kowa nitrate monitor which is not listed above, please phone or email us and we shall be happy to help and to add it to the list.