Diagnosing & Repairing Residential POE Systems
Improve your troubleshooting ability for better repairs
Residential softeners and filters may work wonders when conditioning water, but they will eventually need service. Diagnosing and repairing residential point-of-entry water conditioning systems need not be a profitless, multiple trip ordeal that results in an exasperated service technician and a befuddled customer.
Completing repairs in a timely manner on the first trip will enhance your com-pany’s credibility; leave the customer with a smile; and should provide a good margin for profit. Typically, residents have made a significant initial investment for their treatment system and will be anxious to have it returned to proper operating condition. Let’s look at some ways to make efficient repairs a reality.
Start by arriving on time, or at least let the customer know if you are delayed. Because service repair people have a reputation for being late, it will make a great first impression when you actually arrive near the scheduled time. The service vehicle does not need to be brand new, but it must be neat and organized. A sloppy vehicle leads to an unprofessional appearance, wasted time and unneeded return trips. Because you do not want to pay for steam cleaning an expensive driveway, park on the street if your vehicle leaks fluids or if you may otherwise stain the property.
Be prepared with your own rudimen-tary equipment such as ladders, garden hose, tools and cleaning supplies. Maintain a supply of all the most common repair parts that may be needed. This of course will vary with the types of systems being serviced, but here are a few examples: internal valve parts, motors, gears, transformer, base gravel, resin, carbon, media extractor, distributor, seals, float components and various hardware items. Stocking complete control valve assemblies can be quite advantageous for replacement of the existing controller, or in a pinch to “borrow” a needed part. In any case, being properly prepared is a vital step toward a successful service repair job.
A methodical diagnosis begins with observations and keeping your hands off the equipment. Be sure to document all of your findings because memories quickly fade and the information may be very valuable as you progress through the troubleshooting process.
For softeners, use an accurate test kit to determine the hardness of the untreated water, plus the treated hot and cold water inside the home. If either shows hardness, check the effluent right out of the softener. Before touching the system, note the time of day, meter setting, days or gallons until regeneration, as well as other pertinent information. Make sure there is an uninterrupted electrical supply, paying special attention to any possible switches that might control the outlet in question. Note the salt and brine levels, using a chart if needed to confirm the proper brine volume for a given brine tank size. Performing a thorough overall visual inspection of the equipment and installation will provide an excellent foundation for the subsequent tasks.
The Hard Water Mystery
If you find soft water at the system and in the house, but the customer complains of intermittent or continuous hard water problems, try testing other areas in the home. Many homes have confusing pipe schemes with multiple inlet connections. It is possible that the softener does not feed the entire home. You can turn off the water from the softener and confirm that water does not continue to flow in any locations that should be softened. A system that runs out of softening capacity prior to regeneration will cause intermittent hard water, so check the settings to confirm it is regenerating at the proper frequency. Do not use an arbitrary capacity estimate such as 30,000 grains per cu ft, because this number is based on an unrealistic and wasteful salt setting. You should expect the following approximate capacities per cubic foot of resin based on the noted salt settings.
Look for about 14,000 grains at 4 lb, 20,000 grains at 6 lb and 24,000 grains at 10 lb. The resin charts and manufacturer’s specifications may show higher capacities, but we are not talking about laboratory conditions. Keep in mind that resin loses capacity capability as it ages and a small percentage is lost during each regeneration. A five-year old system may have lost 25% or more of the original capacity capability through fouling and attrition. In most applications, the customer should keep the salt level at or above the water level in the brine tank. Regenerating with a poor brine solution can result in hard water for a week or more.
The hard water problem could be one of perception only. To solve this, instruct the customer how to use a test kit and leave one with them. Let them check the water in real time to determine if it really is hard or soft. There are many other potential causes for hard water, many of which will be addressed as we proceed.
The customer states that the unit has not been using salt and a little investigation shows the softener is producing hard water. Asking what is wrong is like calling an auto mechanic and asking why your car engine is running rough. There are a lot of potential causes, but following a systematic plan will help you quickly narrow down the cause of the problem.
First, we need to understand the basic operation, which will help us to identify potential problems. As hard water passes through the resin bed, positively charged hardness minerals, like calcium, are chemically attracted to the resin beads. The calcium trades places on the resin beads with sodium until the system is significantly loaded with hardness ions. This ion exchange process continues until the resin nears exhaustion, which is indicated by an increase of effluent hardness leakage. It is near this point that the system must be regenerated. System regeneration essentially floods the resin bed with a concentrated brine solution, overwhelming the calcium ions, which are flushed to the drain. The softener is again ready to exchange sodium for calcium and produce soft water. Provided the resin is in proper working order, hard water problems will likely be caused by failure of a concentrated brine solution to flush through the resin, the water failing to contact the regenerated resin or bypassing in the controller assembly. Let’s explore these three primary areas of concern.
The brine solution results from water refilling the brine tank right after the previous regeneration or shortly before the anticipated regeneration. Each gallon of water will dissolve about 2.5 to 3 lb of salt. Thus a 1.5-cu ft softener will generally refill the brine tank with about 3 gal of water. Check the brine tank to confirm the correct water level. Charts are readily available to calculate the amount of saturated brine in a brine tank, which can vary drastically based on size, salt dose and the use of a salt grid. As a general example, an 18-in. diameter brine tank without a grid and with dry salt above the water level will contain approximately 1 in. of water per pound of dissolved brine. In other words, 9 in. of brine works out to be about 9 lb of salt.
If you find significantly less water in the brine tank, look for a refill restriction or incorrect setting. Many systems use a brine tank refill shortly before the regeneration begins, so the brine tank may be without water simply because it was not yet time for it to refill. If you find the brine tank significantly overfilled, look for an incorrect setting causing too much refill or a leaking refill controller. Too much water in the brine tank on its own will not cause hard water, though it can cause intermittent salty water to service following the regeneration.
The most common cause of an inordinately high water level in the brine tank is from the system not drawing the brine out during the previous regeneration cycle. Most systems will simply refill whether or not the water from the brine tank was removed during the previous regeneration. The water will build up in the brine tank, usually until a mechanical float halts the progression near the top. This indicates a failure of the unit to draw the brine from the brine tank. To draw the water from the brine tank, controllers commonly rely on an injector assembly to create a vacuum that will pull the water from the brine tank into the resin bed. The motive flow is directed to a venturi where it accelerates and creates a vacuum. A restriction on either side of the injector assembly or within the venturi itself will result in poor performance. The venturi has a relatively small port shaped like a funnel that can become clogged, causing partial or complete loss of vacuum.
Other common causes of injector failure include interrupted flow to the injector, a restricted drain line and a deteriorated resin bed. Each one of these symptoms must be checked and corrected to allow free flow of the brine to the resin bed.
Next time we will examine further brine failure causes, including anticipated brine draw rates, along with other common softener service issues.