Diagnosing & Repairing Residential POE Systems
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.
The Basics
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.
Troubleshooting
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.
Possible Clogging
Proper brine concentration is a function of many factors that include the injector size, motive flow pressure, brine concentration and injector efficiency. Watch out for a salt bridge where the salt sticks to the sides of the brine tank and prevents contact of the salt with the refill water. Check the brine concentration, preferably using a salinometer. We take a 26% full-strength brine solution, typically dilute it to about 10 to 12% with the injector and hopefully move this solution equally throughout the resin bed at an optimum rate. The draw rate can vary widely depending on salt dose and other factors, but in general, you should expect to remove the brine from the brine tank in approximately 10 to 15 minutes. All of this is good, but has little to do with hard water problems. Even an inefficient or poorly configured injection system will still produce soft water. The capacity will not be great, but if you achieve contact between the concentrated brine solution and resin, the ion exchange process will take place. Detailed brine injection efficiency is most important when targeting capacity or hardness leakage issues. For our purposes, we will concentrate on brine contact and concentration.
The injector incorporates one or more components that work to create a vacuum and draw the brine solution from the brine tank. The relatively small opening of the injector almost encourages clogging. Poor brine draw is often caused by simple clogging of the assembly. Cleaning or replacing the injector may be all that is needed. It is important to replace or thoroughly clean not only the injector, but also the related components and surrounding areas to make sure the cause of the clog is extracted. If you still have poor brine draw, check for a flow restriction in the drain line. A partially restricted drain line flow control will prevent proper suction.
A Poor Resin Bed
A more difficult symptom to diagnose is a deteriorated resin bed. You must physically core sample the resin to determine the condition. Inspecting the resin, you may find that the top section of the resin bed is soft or mushy. New resin is firm and flows through your fingers when squeezed. If the resin is not in good condition, back pressure from the broken down resin bed can prevent proper injector operation. This can also cause channeling of the regenerant and/or service flow resulting in poor brine contact. This, of course, causes lousy capacity and poor soft water results. A poor resin bed can leave salt pockets that fail to rinse adequately, resulting in intermittent salty water to service. Do not try to replace only the top portion of the resin that appears to be causing the problem. I can almost guarantee that you will regret this attempt to save a little time and money.
When in the brine and rinse cycle, there should be a strong suction at the brine pick up tube. If you have good suction strength at the injector, but are not drawing from the brine tank, then you need to inspect the brine pick up and float assemblies. Don’t spend too much time on this inspection. These are good parts to replace as a matter of preventative maintenance. Brine draw is dependent on the valve sending water throughout the internal porting properly. Thus you may need to overhaul the controller’s internal parts to fix the problem. Again, these parts are preventative maintenance items and should be replaced if in doubt. The last thing you need is to have to redo something you should have done properly the first time.
Ion exchange is wholly dependent on the brine solution contacting the resin. If the brine is drawn into the mineral tank but does not pass through the resin bed, you will still have hard water. Check this by first confirming you have a strong brine solution in the salt tank. Put the system into the brine and rinse cycle and confirm that the brine is being removed from the brine tank. Go to the drain line and taste the water coming from the drain line. In a properly functioning system, you will expect to first taste relatively fresh water at the drain. This is the displaced water from the mineral tank.
Next, you should taste a strongly bitter solution. This signifies that the hardness minerals are being driven out of the system. Once the bulk of the hardness has been removed from the resin, you should notice a salty taste that occurs when the brine solution no longer has a significant amount of hardness to remove. If within about five minutes you find that the water to the drain line is salty, shut the system down and check the riser pipe connection. You will want to replace any related seals and the distributor assembly. If the connection between the bottom of the controller and the distributor pipe is not properly sealed, the brine water will enter the mineral tank and as always, follow the path of least resistance. This path will bypass the resin bed, leading directly back through the controller and to the drain line.
Resin-to-Service
Resin-to-service is usually discovered when strainers in the home begin to clog, or you may find resin beads in the toilet tank. If your system is losing media to service, check to see if they are whole beads or smaller particles. If the loss is of whole resin beads, you can count on finding a problem with the distributor assembly. It is important to transport loaded point-of-entry (POE) systems in a vertical position. Putting them into a horizontal position tends to place the weight of the media across the length of the distributor pipe. This can bend and pull the pipe out from the correct position in the bottom of the valve. When set back to vertical, the pipe may damage the seal on the bottom of the controller and may not sit back in the proper position at the bottom of the mineral tank. If there is a gravel base, the rock may slide under the screen of the bent distributor tube. When placed upright, the screen will rest higher than originally intended—on the gravel rather than the bottom of the tank. This essentially makes the pipe too long and can make it jam into the bottom of the controller. This can lead to a distributor failure from the constant pressure exerted on the pipe and screen caused by the shorter area available.
Want a migraine? Have a distributor failure that allows the resin to pass into a home. Not only do you have to repair the system, but the real entertainment is trying to get all the resin out of the house. The resin likes to settle in the water heater, but when you open the drain valve, the resin will stir up and only partially drain from the valve. You have to wait for the resin to settle again to the bottom and repeat the process until the resin is extracted. Transport the system in a vertical position or load the media on site to avoid a world of frustration. If you find that the resin beads to service are consistently very small, check for a system that is plumbed in backwards. Don’t be a hard head and insist that it is plumbed correctly. Water flowing up flow to service will lift the resin fines up to and through the slots of the top screen and into the service flow.
Calculating Water Flow
Hard water is often intermittent. You may find soft water after a system regenerates, but hard water before the calculated regeneration takes place. Last time we covered how to make reasoned, realistic capacity calculations. If all your calculations make sense and everything checks out from an operational standpoint, take a look at another possibility. Hopefully we are no longer using time clock softener systems initiated by a set number of days; these are anathema except in a few specific applications. Most modern systems use a flow meter to count the volume of water used in order initiate the regeneration, at least in theory, just before exhaustion of the systems capacity occurs. Most residential systems can count water flows down to about 0.25 gal per minute (gpm). This seems perfectly adequate, as not many water flow demands fall under this parameter. However, a small leak in a toilet float, faucet or any of a number of other water devices can lead to a huge water flow disparity. A continuous leak of just 0.05 gpm will result in a loss of 72 gal per day of softened water. This is like adding an extra person to the family and not counting their water use. Put on your Johnny Dollar detective hat and correct any small leaks. If you don’t take this extra step, the user will look to you for answers as to why the softener does not maintain soft water at the expected capacity.
Practice these troubleshooting steps and watch your return calls diminish, while your customer service satisfaction and profits increase.
By Jerry Horner, CWS-VI, CI