We are back with more corrective actions. In our post on Cooling Tower Corrective Actions,
Jeff Freitag noted that the role of the plant operator has evolved to include a wider variety of responsibilities. This is true in facilities big and small. Labor power is stretched thinner than ever and too often the new guy is now tasked with testing the water systems. The in-house training could be baptism by fire or “this is what Bob did for the last 30 years.”
It is important to ask your water treater to assist with training and provide testing measures, standards and control charts similar to those shown below. Even with all the tools in place, nothing beats experience!
How to handle out-of-range test results?
When you grab samples and do your testing it is not uncommon to get a result that is out of range. How do you decide what action to take to correct this value? The more time you spend with a system the easier it is to respond to unexpected results.
Let’s take a look at some typical results and how to address these issues.
Experience is the Best Teacher
When working with any kind of mechanical system, nothing beats hands on experience for learning how to manage and maintain things properly. Your water treater can make this easier by helping to simplify the process. Watertech provides log sheets, control charts and a comprehensive manual with each system to take some of the guess work out of maintenance.
Real World Examples
A manufacturing plant's boiler conductivity dropped steadily over the week and was consistently 50% lower than the set point. The boiler conductivity on the controller was reading close to the hand held meter on site. What was happening? The answer to this one was water treatment basics that were confirmed by using remote technology. In general, it’s safe to assume that low conductivity is due to excess water leaving your boiler and high conductivity is related to not enough water leaving your boiler.
After graphing the boiler conductivity and temperature from the controller you can see the conductivity drop while the probe temp remains the same. Since boilers sample intermittently the water temperature will increase with blowdown and decease the longer it sits in the pipe. The steady temp is a good indication there is a constant leak of hot boiler water going past the probe and through the blowdown valve.
In many cases, a quick walk around the boiler to conduct a hand check on the surface and blow-down piping can also indicate where a leak is coming from. It can be tough to get a visual on blowdown piping leaking since most are plumbed direct to a flash tank and right to drain.
Cause: As you can see in the picture the Blow Down Valve is stuck at a 45 Degree angle allowing water by. Fixing the valve will stop the flow and allow the conductivity to come back into range again. As you can see on the graph above, the repair was made on Feb 21st with an immediate drop in probe temp and a gradual increase in conductivity.
A customer started seeing conductivity levels in the DA that were 6 times higher than normal. When this happens, there could be many contributing factors, so a deep understanding of how your plant operates is critical. The first thing to check would be all the make-up sources to the DA, in this case the sources were RO and condensate. There were no issues with RO as the conductivity was low. The condensate however had elevated levels of conductivity. Looking back on the condensate conductivity logs over the last 2 weeks confirmed suspicions.
This is a large facility, so it was necessary to start checking the conductivity at heat exchangers and any possible cross connections. The condensate water was soft and didn’t have any indication of product contamination, so it seemed that the leak was on a soft water side of a heat exchanger. After 3 hours a bad jacket was found on a water heater. While it took time to find the source of the elevated levels of DA conductivity the payoff is tremendous since the high conductivity led to lower cycles of concentration and extra make-up water, gas, and chemical.
Another source to check for contamination would be boiler carryover. Carryover is when boiler water leaves with the steam. Typical causes of carryover are contamination, increased steam loads and elevated levels of alkalinity – none of these were the case in this situation.
Whether you are new to managing the water systems at your facility or have been doing it for many years, the best advice is to look at your corrective action plan and KEEP IT SIMPLE! Our experiences have shown that most changes occur from mechanical issues or probes needing a calibration. Start with small changes and re-test. All these fun facts and more can be learned from your water treatment professional or by attending our Watertech University training sessions. If you have additional questions please reach out to us at 414-425-3339 or firstname.lastname@example.org
||Jason Waack | Territory Manager, Watertech of America, Inc.
Jason has over 15 years experience in the water treatment industry. He has been a Territory Manager with Watertech for 5 years, managing accounts in the central part of Wisconsin.