Common Pool Heater Error Codes Explained + How to Fix

A pool heater makes swimming possible in the cooler months of the year. So you can use one to start swimming sooner or extend it. But here’s the kicker! Like all machines, pool heaters can fail or malfunction, and during that time, using the pool can be daunting.

If you run a commercial pool, this will translate to lost revenue. And if you have a domestic swimming pool, it would mean no fun for you, which can be devastating.

The best way to solve pool heater errors is to know where the problem is coming from. The good news is, you don’t have to stress over it when you have pool heater error codes.

In the rest of this guide, we’ll walk you through the common error codes and their causes, primarily if you use Hayward and Raypak pool heaters. So, let’s get to it!

Common Error Code Causes

An error code is a feedback you get when a process fails. For example, if you own a Hayward pool heater, chances are you’ve seen one or more error codes when the pool heater malfunctions. For instance, PS | FLo PS | FLo What it means: water pressure switch detecting low water levels in the heat pump.

How to fix it: Check that pool pump is receiving enough water. Ensure that your pool pump is sending water to the heat pump. For variable speed pool pumps, try putting the pump speed up a notch Check for any clogs or backups causing poor water circulation.

The same is true if what you use is in your pool is the Raypak pool heater.

Hayward Error Codes

Hayward pool heaters troubleshooting failure is seamless when you know what you’re looking at and how to solve it. Below are the different Hayward error codes and their causes. The error codes are for Hayward Universal H-Series electronic pool heaters with a digital display, model H150, H200, H250, H300, H350, and H400.

Hayward Heater LO Code

The Hayward pool heater LO error code is a result of several issues. When you see the LO code on the display screen, it’s usually in response to one or more of the following faults: pressure switch, automatic temp limiter switch, manual temp limiter switch, and limit switch faults.

Pressure Switch Fault

There are multiple ways to diagnose the pressure switch fault. Start by verifying that the pump is running. If it’s not, please turn it on. If this doesn’t work, proceed to check switch wiring and connections. In particular, look for kink or rodent damages. You’ll also want to check terminals for breakage or corrosion.

You can also diagnose the pressure switch fault by measuring switch continuity. Start by removing the wires, then measure the OHMS with the pool pump on. If it’s closed, the switch is okay. If it’s open, reconnect the wires and proceed.

Another way to diagnose the pressure switch fault is by checking the water flow. First, ensure the filter and pool pump baskets are clean and no blockage in the impeller. If you have a dirty filter and pool pump baskets, you’ll need to clean them. Also, unblock the impeller if there’s a blockage.

Adjusting the pressure switch can also work when diagnosing the pressure switch fault. So, turn the adjustment screw 1 on clockwise to see if the LO error code disappears. Lastly, the fault could be a result of a defective pressure switch. In this case, replacing it is the best solution.

Automatic or Manual Temp Limiter Switch Fault

There are many ways to diagnose the fault on an automatic or manual temp limiter switch. You can start by checking the switch wiring and connections. Inspect wires for kinks or rodent damages. You should also inspect the terminals for breakage or damages.

Measuring switch continuity can also help. So, remove the wires and measure OHMS with the pump on. If it’s closed, the switch is okay. But if it’s open, reconnect the wires and proceed.

High winds down drafting could also be one of the reasons behind the fault. Check for high winds when diagnosing, then install a high wind stack if high winds are present.

You may also want to check for restricted or blocked exhaust. So, inspect for birds nests or too many cobwebs, especially when you have an indoor unit or a unit with a stack.

Sooted or damaged heat exchangers can also cause the fault. Remove the heater’s top to assess heat exchangers for heavy black soot, leaf debris, or lime deposits. Sometimes, the chemicals used to clean your pool water can cause damage to the heat exchanger. It could just be a loose connection that you need to tighten or colder winter temperatures, but you may also need to replace the heat exchanger.

A defective temperature limiter switch can also cause the fault. You can reset the manual temp limiter switch to solve the problem. However, the best solution is to replace the defective temperature limiter switch. Then, do the same for an automatic temp limiter switch.

Limit switch Fault

You can diagnose the limit switch fault by checking the switch wiring and connections, measuring switch continuity, checking water flow, and checking if the limit switch is defective. When checking the water flow, ensure the flow rate is greater than 25 GPM. Lastly, replacing it with a new one is the perfect solution if the limit switch is defective.

BO Code

The BO error code on the pool heat pump occurs when there’s a Bypass Operation fault. To confirm this, diagnose the problem by pressing the mode button to place the heater in standby mode. Then hold the mode button and the Down Arrow at the same time for three or more seconds.

IF Code

The IF error code occurs when there’s an ignition failure fault. Here are the many ways to diagnose the error. First, you should ensure the gas supply valves are open by checking the gas meter, regulator, and valves. 

Alternatively, you can check the gas volume supply and gas line size. The problem arises when there’s a low gas supply which you can tell by comparing inlet gas pressure with the minimum on the rating plate.

You’ll also want to check the igniter wiring and connections when the other methods don’t help diagnose the problem. Inspect the gas valve wiring for kinks or rodent damages. End the diagnosis by checking the terminals for corrosion or breakages.

Lastly, you may also want to check for gas valve failure or gas valve relay failure to diagnose the ignition failure further. Do this by measuring the voltage across the gas valve during ignition.

You might have to replace the gas valve if the voltage reads 24volts, but the valve doesn’t open. However, if the voltage doesn’t read 24v, you may have to replace the relay.

SF Code

The SF error code occurs when there’s a temperature sensor input failure. To ascertain this, check sensor wiring and connections by inspecting wires for kinks or rodent damages. Also, examine the terminals for any breakage or corrosion.

Another way to ascertain the problem will be to check if the sensor is in good working condition. Replace the temperature sensor when you notice it’s defective.

HS Code

The HS error occurs when there’s an overheating problem. The water temperature in the pool exceeds 104°C during this period. First, check to verify the remote thermostat is in good working condition. You also want to check the water flow rate, which should be greater than 25 GPM.

HF Code

The HF pool heater error occurs because of a flame sense fault. Ascertain the flame sensor is in perfect working condition and replace the igniter if the error persists.

Raypak Error Codes

Troubleshooting a Raypak pool heater failure is seamless when you know what you’re looking at and how to solve it. Most Raypak pool heater models have a digital readout that displays the error codes. Below are the different Raypak error codes and their causes.

BD1 Code

The BD1 error occurs when there’s a control board failure problem. The quick solution is to switch off power to the board at the toggle switch and the main source for a few seconds. Then, turn it back on and observe if the error persists. It’s advisable to replace the board if the BD1 error code persists.

EEP Code

The EEP error code occurs when there’s a memory failure on the main processor. The quick solution is to switch off the power at the toggle switch and the main source. Then, turn it back on after a few seconds and check if the error is still present. If the error doesn’t go away, replacing the board is the best solution.

FAN Code

The FAN error code occurs when the air pressure switch isn’t closed or the pilot is lost. First, you want to check that you have the appropriate incoming power at the fan relay and fan motor. Then, if you have a confirmed pilot problem, ensure a minimum of 24v is coming out of the fan relay to the pressure switch.

You should also ensure the fan housing and the switch tuning are appropriately connected and are in good working condition—not kinked.

FFL Code

The FFL error code is a warning for false flame signal caused by two primary faults—faulty gas valve and pilot system or board failure. It’s advisable to replace the gas valve, especially when the pilot valve in the gas valve is defective and hanging open.

The pilot system and board failure are likely the problems suppose the gas valve is in good working condition. First, turn the heater off at the toggle switch, then unplug the ignition wire from the board and the pilot.

You also want to remove the green ground wire from the burning tray. Then, clean all the wires and reconnect them back. Lastly, turn the power on the toggle switch. Replace the board if there’s no spark at ignition.

GVC Code

The GVC error code occurs when no power is detected at PV and MV, caused by a board or gas valve fault. First, diagnose the problem by disconnecting the power and the board’s ignition wires and gas valve wires.

Turn the power back on. You should see a spark at the module. Replace the board if there’s no spark.  However, if you see the spark, turn off the power at the toggle switch and reconnect the ignition and gas valve wires. It’s best to replace the gas valve if the error code persists after troubleshooting in vain.

GVO Code

The GVO error occurs when power is found at the PV or MV at the wrong time. It’s caused by a board or gas valve fault and low power to the transformer. Handling a GVO error code is similar to GVC error code.

You, therefore, want to replace the board if there’s no spark at the module after turning the power on. Besides that, replace the gas valves if the error code persists.

HL1 & HL2 Codes

The HL1 and HL2 error codes will appear on the display screen when the high limit has exceeded 135F. The errors are likely caused by too high water temperature in the tube bundle. Many things could go wrong, leading to HL1 and HL2 errors.

So, you should check for blockage in tubes or low water flow problems. Remember to check the unitherm governor and the bypass assembly. Replace the unitherm governor, the spring, and the bypass if necessary.

IGN Code

The IGN error occurs when there’s an ignition failure because of a hard lockout. First, disconnect the power supply to the unit to help clear the lockout. Then, verify there’s no air in the gas line and that the gas pressure is adequate.

ILO Code

The ILO error occurs when there’s an ignition lockout. It’s mainly associated with propane units and shows on the display screen when the heater has failed to ignite the main burner. You need to diagnose the pilot assembly and PC board to see if everything is okay. Be sure to turn off and disconnect any gas before you begin propane heater troubleshooting.

PRS Code

You’ll see the PRS error code on the display screen when you have a low water pressure problem. There are plenty of solutions to this problem.  First, ensure the pool water level is at the middle of the skimmer face.

The pump should also be running smoothly. Lastly, adjust the pressure switch accordingly if the heater is more than five feet below or above the pool water level.

ROL Code

The ROL error occurs when the thermal fuse melts and falls because of excessive heat. It’ll also be shown when a flame roll-out is detected in the unit. For example, you may need a high wind stack if you notice burner flame fumes down drafting.

SNS Code

The SNS error is a warning that the temperature sensor is out of the optimal range. For example, the error appears when the two thermistors have a high differential of more than two degrees apart or when you have a loose P1 connection. Fix any of these faults, and the error code will disappear.

Troubleshooting Options

Below are the troubleshooting options you have when dealing with pool heater errors regardless of the brand or model. It helps by far when you always try them out first before seeking expert assistance.

1. Investigate Power Source

Many pool heater errors occur because of power problems. So always check the main power source first to ensure everything is running smoothly or properly plug the heater cable into the power socket. Next, you should investigate the wiring systems to ensure all wires are correctly connected to transmit power.

2. Check the Temperature Settings

Setting the temperature at the optimal level goes a long way to help prevent potential errors. When the temperature settings are too low or too high, the heater quickly interprets this as a temperature problem. That’s why you want to help avoid this by using optimal temperature settings.

One neat DIY trick to use when regulating the temperature is setting a solar cover on your pool heater. This solar cover helps keep your heater from losing any heat that it generates during its run time. Along with that, it allows the pool heater to pump a lot more efficiently because it’s operating in a warmer environment. 

3. Refer to Your Model’s Manual for Error Codes

No troubleshooting method works better, like turning to your model’s manual. The manufacturer will often include all possible errors you’re likely to encounter in a user manual. Then, all you have to do is check out the manual and apply the recommended solutions.

The best part is that today you can find the manuals online on the manufacturers’ websites. So, you shouldn’t be worried if you don’t have your hard copy. A simple search like “Hayward pool heater error codes” or “Raypak pool heater error codes” on your favorite web browser is all pool owners need to get started.

Here is the Hayward Pool Heater Manual.

4. Inspect Parts of the Heater for Malfunctions, Rust, and Leaks

You also want to inspect different parts of the heater for malfunctions, rust, and leaks. Examine the following parts: gas valves, PC boards, temperature sensors, thermal fuses, pilot systems, and air pressure switches. Also, check for rust, leaks, or loose connection wires.

Frequently Asked Questions About Pool Heater Errors

The Bottom Line

There could be so many reasons behind a faulty pool water heater. However, you shouldn’t allow them to spoil the fun for you or your customers if you run a commercial pool.

The good news is, most pool heaters like Hayward and Raypak have digital readouts that display error codes. If you were the least worried about pool heater error codes and how to interpret them, we believe you found this guide enlightening.