Running cold: how to effectively diagnose heater problems in older spas

Just as arthritis and other ailments tend to creep up on us as we age, portable spas also can develop a few aches and pains as they grow older. One of the most common service call problems on older spas is heat-related--from complaints of low heat to no heat at all.

When a complaint comes in, it is crucial to have a few background facts, including the spa make and model, its power supply, its location (indoors or outdoors) and the breaker accessibility. The customer may not be familiar with this information, so it wouldn't hurt to keep a written record for all your customers. That way, you'll have the information right at your fingertips. To be sure, familiarity with the equipment certainly will give you an advantage.

The troubleshooting process should begin the minute the customer calls. Often the problem is not with the heater itself: The circulation system, the power source or another component could be at fault. Asking a series of questions over the phone should help you isolate the problem--and can eliminate the time and cost of a trip out to the job site. Here are a few key questions you should be asking:

Is the unit plugged in? Is the power on?

Seemingly silly questions, but you'll be amazed at how often this can occur.

At what temperature is your thermostat set?

If the thermostat is set too low, the water will not heat up substantially. Adjusting the thermostat higher will solve the problem. Check the thermometer in the spa if your temperature margins are only a couple of degrees off. Floating thermometers do go bad.

Have you cleaned the filter lately?

A dirty filter will impede the flow enough so that the pressure switch will open and the heater will be disabled. The quick fix? Remove the filter for a short while to test if the heater comes on. It may be time to clean or replace the filter elements.

Have you changed the water recently? Is the spa full? Is the water moving?

A freshly filled spa can become air-locked. Low water levels can affect water flow. Once the water level is correct, the system needs to be bled to let the air escape. With a full spa, the water may not be moving properly. Ask your customer to switch the pump to high speed to be sure that the water is flowing. Just because the pump is on doesn't mean water is moving. You'll want to determine the flow either visually or by feeling the water. Have customers check with their hands to be sure the water is moving. If there is reduced flow or no flow, the pressure switch will be triggered, causing the heater to be deactivated and resulting in the heat loss. This is a long shot, but you never know. Some spas are more prone to air-lock than others are.

Has the high-limit switch been tripped?

Usually the high-temperature limit switch tripping is an effect of the thermostat or the pressure switch not functioning properly. The switch can be reset by simply pushing the typically red button located on the spa pack's control panel. The high-limit will not reset until the water has cooled down. Mechanical high-limits trip off at roughly 109 degrees Fahrenheit. If the spa is cold and the limit trips, look for water flow issues.

What's the status of the ground fault circuit interrupter?

While helping homeowners sort through GFCI issues and troubleshoot the tripping breaker, be sure they reset the breaker correctly. It should be turned all the way off and then back on. If you press the test button, the GFCI should trip off if it is properly energized. If the breaker trips instantly, there's a fault somewhere. Try turning the heat off and resetting the breaker. If the breaker holds, most likely the fault is in the heat system. Check all related heater components. Most likely it is a bad element. (See GFCI section.)

On-site investigation

After you've exhausted all your telephone troubleshooting, you'll need to schedule an on-site visit. When headed out, you will want to take along your trusty volt/ohm meter, amp meter. Using a meter daily and becoming used to its operation is a must for technicians. Without it, you're just guessing and costing precious time on the service call. A meter is a tech's most important tool.

It pays to keep a few key replacement parts on hand when repairing older mechanical systems. For older spas, there are four primary heater elements: the 5-by-5 square flange Brett style, the 1 1/4 threaded style, the flow-through style and the round flange. If you carry these, along with pressure switches, high-limits contactors and a few common relays, you should be able to repair any old-school mechanical unit in one visit.

Once you're on site, take a few minutes to survey the unit. Do a visual inspection to look for the simple culprits--and to confirm the information that the customer gave you over the phone.

First and foremost, be sure the unit is plugged into a power source. Verify that the water level is correct and that the water is moving properly throughout the system. Next, assess whether the skimmers are properly covered and free from blockage. You should also inspect the suctions to ensure that they are free from blockage.

Always go through the functions of the spa to confirm that low speed is working at the correct sequence. For example: The pump comes on when the time clock is activated or the thermostat is turned up.

When low speed is on and the heater indicator light is on, we know that voltage is going to the heater element. So break out your amp/volt meter and confirm that voltage is at the heater element. If there's voltage at the element, always measure amp draw. This is the quickest method to test to see if the element is working properly. If it's drawing amps, it is heating. If it's not drawing, you have a bad element. (See the amperage section.) Signs of oxidation on the terminals are a sure sign of a bad element. Improper water chemistry is the No. 1 reason for premature element failure.

Check out the spa's electrical line. Is it a 120volt, 20-amp GFI dedicated circuit, or a 240volt, 50-amp GFI dedicated circuit? Most of the older spa units are 120/240 convertible. By switching a wire harness or a toggle switch, the spa will operate on either power supply. The additional 120V leg is there to supply the heater with more power, which allows the water to be heated faster (120V spas heat at approximately 2 degrees per hour, while a 240V spa heats up at roughly 8 to 10 degrees per hour).

Because the heater element uses more electricity than any other component, the wire gauge will be thicker. The wires will run through a contactor or relay able to handle a large amp draw. This amp load is separated because most control relays don't handle high amp draws well. Coils look for sufficient electricity to close the bridge once proper electricity passes through. The coil pulls down and electricity flows to the next bridge or pathway until it reaches its final destination, the heater element.

* Voltage: In our example, let's assume that the spa is 240 volts and has a control system voltage of 120 volts. The pump on the unit is on. Because the spa features convertible voltage, take out your meter, which should have the capability to test continuity, volts and amps. One meter will be able to test all of these methods. Begin methodically tracing voltage through the control system. Starting at either end of the wiring, beginning or end, check if the voltage passes through. I like to start at the end with the heater element and follow the wiring backward to a contactor or switch. In this process, I can determine if volts are traveling to the element and whether they are at the correct voltages. In this case, it will be 240V at the element.

* Amperage: If voltage is present, switch the meter to amp draw to determine if power is being used. Often the indicator light will be on, but the spa will not heat if it's not drawing current/amps. You will find anywhere from 22- to 28 amps, aka kilowatts, on a 5.5kW, 240V system. A 1.5 kW, 120V heater will draw between 10- to 16 amps. If we find amp draw, the element is heating. If the element is getting correct voltage but not drawing amps, we know it's bad. This method is the best way to establish that the element is working properly and will save you many wasted service calls if you test for amp draw before leaving the site.

* Ohms: Another way to test elements is an ohm test. An ohm or continuity test shows if a conduit (that is, wire, switch or contactor) is making contact/closed. By testing ohms/continuity, you can tell if the element has a break in it. You would read an open reading on your meter if it's bad. You would read 9 ohms +/-1 ohm if it's good.

* GFCI: Also associated with a bad element is a GFCI breaker tripping often or immediately. A quick technique to diagnosing a tripping ground fault breaker is to turn the power off, and then disconnect the two wires at the heater element leads, being careful not to snap the studs off. Hang the wires in mid-air and turn the power back on. Then turn on the heater circuit. If the breaker does not trip, you know that the element is bad and should be replaced. This test is not for the tech who is uncomfortable with electricity.

You may want to protect the hot leads you've just removed with electrical tape so that nothing can touch them. If the breaker still trips, disconnect all the components: pumps, blowers, ozone and lights. Once the GFI stops tripping, plug everything back in, one by one. When the breaker trips, pay attention to the wire that made it trip and simply follow that wire to the source and begin troubleshooting the particular component.

Tracing the problem

If the element is not getting correct power, the control circuit should be your next suspect, which is important to keep in mind when working on older mechanical systems. There are many different styles of electro-mechanical spa controls; however, all have the same principles of operation, using coils to switch components on and off. A malfunction in a switch, coil or contactor, located along the heater's electrical path could be causing a problem.

Pay close attention to the pressure switch, the high-limit switch or the thermostat. These protective devices, which come in many different styles, shapes and sizes, are wired to a coil either in sequence or in a series to close the bridge, which allows voltage to flow to the heater. All these switches could be bad at once, or it could just be that one device is your problem child.

When testing the wiring, follow the heater wires back to one contactor to see where power stops, then measure the voltage at the coil. If you have the correct voltage reading at the coil and it won't close, it's bad. At this point, replace the contactor.

If there's no voltage reading, put one side of your tester on the common side of the coil and follow the wire back through the heater control loop to determine which one of the three switches is not letting power through.

* Pressure switch

Test to see if voltage is passing through the pressure switch. If not, ask a few questions. The flow was checked at the beginning of the call; is the filter dirty? Maybe the pressure switch is not closed? Why won't the switch close? Are the valves closed or broken? Pressure switches commonly fail due to corrosive water. If the switch looks rusty with water damage, it's probably time to replace it. If there's proper flow in the system, perhaps the switch is out of adjustment or defective. When resetting the switch, be careful not to adjust it too low--keep it set between 1 to 5 psi.

* High-limit switch

Backtrack farther and evaluate the voltage going to the high-limit switch, which is designed to turn the heater off if the water exceeds a preset limit--typically 109 degrees Fahrenheit. Is voltage passing through the switch? If it isn't, push the reset button. If you feel a click, it was tripped. Why did it trip? Did the spa really get too hot? Or was it that the flow was so reduced that water was not passing by the heater quickly enough? What about: A dirty filter? Closed valves? Bad thermostat? The high-limit switch trips for a reason. You need to figure out why!

* Thermostat

Next, it's a good idea to check and see if the voltage is passing through the thermostat, which should be set between 58- and 104 degrees Fahrenheit. If no power is getting through, then the thermostat is bad. Be sure to check the spa for overheating because the thermostat will stay open and not allow voltage to pass.

ShowTime

Who: Michael Tierney

What: "Understanding Older Spa Systems"

Where: 2003 International Pool & Spa Expo, New Orleans.

When: Friday, Nov. 7, 8-10 a.m.

Attendees will gain a better perspective on the ins and outs of older spa systems, and learn how to trace malfunctions and repair problems in one visit. The seminar also will focus on controls, switches, basic troubleshooting techniques and repair procedures.

COPYRIGHT 2003 Hanley-Wood, Inc.
COPYRIGHT 2003 Gale Group