Shouldn’t an Electronic Water Level Controller be built to last? Shouldn’t the entire controller unit never need to be replaced? Both of these requirements are certainly possible with the right choice of product.
Major Failure Points
All electronic water level controllers have two major failure points – the relay in the controller that drives the solenoid valve and the solenoid-actuated valve itself. These are typically the only moving parts in an electronic water level control system. The field technician or facility maintenance person needs to be able to easily and quickly diagnose which part has failed.
The relay and valve fail for different reasons. The contacts on the relay fail after many years of operating the valve. However, when properly matched to the valve, they can last up to two million strikes before they fail – typically seven to twenty years depending upon the environment.
The solenoid valve has two failure points – the coil and the plunger inside the valve. This part takes the brunt of the work and should be rebuilt every five years as part of a proper maintenance schedule.
Here are the three things to look for in an electronic water level controller so you can trust it to perform at the highest standards and be cost effective over the lifespan of the cooling tower.
1. Integrated Diagnostics for Easy Troubleshooting
A field technician or facility maintenance person should be able to easily diagnose the problem without taking the entire unit apart. To make troubleshooting easy and fast, look for a controller with the diagnostics built into the controls. Look for a controller that uses LED lights that go ON when the relay and solenoid valve are operating and OFF when they are not operating.
The controls should also include an onboard test switch to allow the controller to automatically sequence through the functions as the operator watches the lights come on, hears the relays activate and sees the valves turn on. This type of system makes it fast and easy to successfully diagnose the problem in the field and does not require any other technical knowledge.
2. Modular Parts for Easy Repair in the Field
Once you’ve identified what’s wrong with the controller, now you need to fix it in the field. The entire water level control system should be designed so a field technician can easily remove and replace only the necessary parts—not the entire unit.
The relay that operates the solenoid valve is the main component that fails inside the controller. Look for a controller that provides easy access to the relays and allows those parts to be easily removed and replaced.
The solenoid valve should be easily rebuilt without removing it from the piping system. The manufacturers of these valves have rebuild kits, so be sure you know the manufacturer of the valve and the part number for the valve and rebuild kit. Keep one of each on hand, because you never really know when it’s going to fail.
The other parts of this system can also fail, but not as often. They should also be easily replaceable in the field. These parts include transformers, printed circuit boards and the sensor. Look for a product that is modular in design so you can replace only individual parts that have failed or worn out, not the entire product. It is cost prohibitive to own any water level controller that does not have interchangeable parts that you, as the operator, cannot replace.
3. Safety Certification by a Third Party
Another important aspect of controls like these are the third party validation required by any Building Department Inspector or authority having jurisdiction. A properly “Listed” product means that an independent third party has tested and evaluated the product as a “System” to be safe to use for the application intended. When a product or System is not Listed, there can potentially be dangerous safety issues. These products fall under the UL508 Standard for Industrial Control Systems.
Third party validation is labeled as a “Listed” Product for a “System” by UL, CSA or ETL in the United States and Canada. Some OEM’s of Cooling Towers try to get by with saying the “Cooling Tower System” is Certified or Listed and therefore the electric water level controller is. But recently, CSA rejected this idea and required cooling tower manufacturers to remove the electrical water level controller until they had third party certification with a listing as a “system” or a controller that is “Certified and Listed” by a third party.
Electronic Water Level Controls for Cooling Towers are certified under the UL508 Standard and/or the equivalent Standard for CSA. Listed Products carry a Logo Mark of the Agency which Listed the product directly on the product. The two major Agencies are Underwriters Labratories (UL) and Intertek Testing Services (ETL).
Enjoy the Savings
If you choose the right electronic water level control system, it will be very safe and cost less to operate than even a mechanical float system over the entire lifespan of the cooling tower. As an illustration, if the mechanical float in a cooling tower is replaced every three years, at a cost of approximately $300 each, plus installation, then over 25 years you will have paid a total of $2,400 for eight floats. Compare this to a total of less than $500 for a simple $20 replaceable component part every ten years plus the cost of rebuilding the solenoid valve every five years at a cost of $75 each. As this example illustrates, the right electronic water level control system can save you thousands of dollars versus mechanical floats over the expected life span of the cooling tower.
Third party validation to meet electrical codes
Reasonable Warranty for the product
Easy access to Experienced technical product support
This article is written by Bill Seneff, President of Waterline Controls – a manufacturer of Electronic Water Level Controllers for twenty years. For more information, you can contact Bill Seneff at firstname.lastname@example.org or (888) 905-1892.