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Raypak Heater Fault Code Guide

No one likes to get an error code on any piece of technology, especially on a Raypak heater. It means something is wrong and needs to be addressed soon. The panic really doesn’t set in until you realize error code BD1 means absolutely nothing to you. Error codes are both curses and blessings. Although an error message is never really a good thing, at least it’s an indication of what the problem is. Just imagine how much easier it would be to diagnose diseases if humans came with error codes.) Usually, depending upon the manufacturer, the manufacturer will include a manual detailing what may have triggered the error message and possible solutions to fix the issue. All error code guides are not made equal.

Still, even if the error codes were listed in the manual, what are the odds you know where that manual is? Unless you’re like my mom who keeps all her paperwork in a filing cabinet, the manual was probably tossed a week after your product was working properly. Heaters, though, can be rather tricky without the manual. I love the saying, “hindsight is 20/20,” because it’s so true. How many times did you wish you kept something after you have convinced yourself that you didn’t need it and threw it away? Or maybe it’s just me.

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Our goal with this blog is to aid you in identifying and defining the error code on your Raypak heater and to provide possible solutions, as per the manufacturer. If we don’t have a solution or do not address your particular issue, it’s always best to contact Raypak directly.

The majority of Raypak heaters will have a digital readout. The digital readout helps pool owners read error codes on the actual heater. The models with digital thermostats are programmed to display a variety of status and diagnostic messages, depending on the operating conditions.

They are also equipped with onboard diagnostic controls. If there is a safety fault, a fault code will be displayed along with a service indication. (see pic on right) The word “SERVICE” will flash on and off if the PC board detects a known issue. The fault code is displayed in 3 big letters in the lower left of the display.

Below is a chart we created to help pool owners identify the meaning of Raypak’s fault code. It also includes possible solutions to fix the issue. Keep in mind, this is not a substitute for the installation and operation manual. Should you need further advice or technical information, please give Raypak a call at 805-278-5300.

Fault Code DisplayDefinitionPossible Solutions
BD1Board failure1. If this code appears and stays on, turn off power to board at toggle switch and source, then re-establish power.
2. If code reappears, replace board as the main processor failed to start.
EEPIndicates that memory failed to start on main processor.1. Turn off power at toggle switch and source, then re-establish power.
2. If code reappears, replace board as memory has failed.
FANIndicates the Pilot was lost, or the air pressure switch is not closed when required. 1. Check for correct incoming power at fan relay- 120V or 240V and at fan motor.
2. If pilot is confirmed, check for 24V minimum out of fan relay to pressure switch.
3. If switch does not make when fan is operating, verify the tuning between fan housing and switch is connected and is not kinked.
4. Soft lock out after 3 attempts- automatically resets after 5 minutes.
FFLIndicates a false flame signal. 1. Check to see if pilot is staying lit after CFH is satisfied. If pilot stays lit, the pilot valve in the gas valve is hanging open. Replace gas valve.
2. If gas valve is working properly, problem lies with the pilot system or board. Turn power off at toggle switch.
3. Unplug ignition wire from board and pilot and remove green ground wire from burning tray. Clean and reconnect ground wire.
4. Turn power on. If no spark at ignition module, turn power off and replace the PC board.
4. If you saw a spark at Ignition Module, turn off the power and reconnect wires.
6. Turn power on and unit should fire.
GVCNo power detected at PV or MV when commanded.1. Turn power OFF and disconnect Ignition Wire and Gas Valve wires from board.
2. Power ON and watch for spark at module.
3. If no spark, turn power OFF, and replace board.
4. If spark is observed, turn off power and reconnect wires. The unit should fire.
5. If unit does not fire and code reappears, power OFF, disconnect valve wires from board and remove MV, PV, and ground wires. Clean and reconnect.
7. If unit does not fire, replace the gas valve.
GVOPower found at either PV or MV at the incorrect time.1. Turn power OFF and disconnect Ignition Wire and Gas Valve wires from board.
2. Power ON and watch for spark at module.
3. If no spark, turn power OFF, and replace board.
4. If spark is observed, turn off power and reconnect wires. The unit should fire.
5. If unit does not fire and code reappears, power OFF, disconnect valve wires from board and remove MV, PV, and ground wires. Clean and reconnect.
7. If unit does not fire, replace the gas valve.
8. Low power to transformer can cause a GVO fault.
HL1The high-limit has exceeded 135F1. Possible excessive water temperature in the tube bundle. Once heater cools, high limits resets automatically.
2. Check for blockage in tubes.
3. Check for low water flow.
4. Check Unitherm governor- replace if necessary
5. check bypass assembly- replace spring or bypass if necessary
HL2The high-limit has exceeded 135F1. Possible excessive water temperature in the tube bundle. Once heater cools, high limits resets automatically.
2. Check for blockage in tubes.
3. Check for low water flow.
4. Check Unitherm governor- replace if necessary
5. check bypass assembly- replace spring or bypass if necessary
IGNIgnition failure1. If the unit fails to hold a flame after 3 attempts, it will go into a hard lockout. Interrupt the power supply to clear the lockout and check for air in the gas line or not enough gas pressure.
2. IGN only appears after pilot has proved and main valve has been powered.
ILOIgnition lockout (Propane units only)1. The heater has performed too many attempts to ignite the main burner and will take a short break.
2. Inspect pilot assembly.
3. If pilot assembly is OK, then the culprit may be your PC board.
PRSLow water pressure1. Check water levels at skimmer face. (should be middle of skimmer face)
2. Ensure pump is running.
3. Check filter pressure. Backwash if necessary.
4. Check heater location- if more than 5 ft above or below water level- adjust pressure switch.
ROLThermal fuse tripped inside heater due to excessive heat or flame roll-out detected.1. Possible downdraft of burner flame. If sensor has red reset button, press button & determine cause.
2. Does your unit need a high wind stack?
3. Check wiring for burns- especially the ground wire and wires at gas valve.
4. Replace wires if necessary.
SNSTemperature sensor is out of acceptable range.1. Water temperature is below 36F or above 110F
2. If the two thermistors are more than 2 degrees apart, the SNS code will appear.
3. Loose or corroded connection at P1.
4. If the sensor is not mounted all the way into the JACO fitting on the header, it may give a false reading.

Raypak Heater Parts

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  • Heat Exchangers, Thermostat
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author avatar
Charlie Ramirez
Writer at InyoPools.com, brings a wealth of knowledge and expertise in pool care and equipment, helping pool owners make informed decisions for over a decade.

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310 responses to “Raypak Heater Fault Code Guide”

  1. Steve Avatar

    So I think I understand. Since the code HL1 comes up within about 15 seconds after turning it on, it is probably a bad high limit switch? The pilot never clicks or turns on. It just says cfh for like 15 seconds, then the hl1 code. It just seems that since it isn’t even heating up, it can’t be hitting 135 f in the water. Thanks

  2. Steve Avatar

    Hi. Great site here. I have a raypack P-M266A-EP-x. I get a CFH, then an HL1(with the Service Flashing). We don’t use the heater often, but only in the hot tub once in a while. I looked up the HL1 code and it says something about the temp being too high for the high limit. The only thing is it won’t start up in the first place, so no heat is being generated.
    Thank you

    1. Matthew Simmons Avatar

      HL1 is a high limit trip. With the pump on, this switch should reset as the water in the header cool- the heater should fire again. If it doesn’t reset, then the hi-limit switch could be bad.

      If the heater is cycling on and off on the limit switch, then it is a low water flow condition. Inspect the bypass in the header and confirm the integrity of the bypass spring. The high limit trip is telling us the water in the header is exceeding 135 degrees. Water is not moving through the exchanger fast enough causing it to super heat.

      1. Steve Avatar

        So I think I understand. Since the code HL1 comes up within about 15 seconds after turning it on, it is probably a bad high limit switch? The pilot never clicks or turns on. It just says cfh for like 15 seconds, then the hl1 code. It just seems that since it isn’t even heating up, it can’t be hitting 135 f in the water. Thanks

  3. Gene O Avatar

    I have an older Raypak P-R206A-EN-C. After CFH, SPK sequence I get CLK, or sometimes heat for a minute then CLK. I do not have a clock/fireman switch.
    It is clearly an failure. What is strange is that if I put pressure on or below the LCD screen, the CLK can disappear and the unit will heat? I don’t know how long because obviously I can’t stand there with my finger on the screen.

    I am about to replace the control board but now I think the LCD may be creating the open?

    1. Matthew Simmons Avatar

      It could be the long pin connector on the back of the board. On that connector, you will see a red loop of wire labeled fireman switch or CLK. Try wiggling that wire as the unit is calling for heat. If the heater sparks and fires, then the connection inside the plastic connector has been lost. Probably some insulation crept down the wire and interfered with the connection. Try a new section of wire harness. If that doesn’t work, it could be the pin on the board or failure inside the PC board. But try the wire first.

  4. Christopher B. Avatar

    Getting an “ILO” error. Are there any troubleshooting tips to address this or do I just need to call a tech?

    1. Matthew Simmons Avatar

      ILO is ignition lockout. If this is a propane heater, they have a 90-second lockout that is required by code. Basically, the pilot is not proving within 90 seconds. You should be able to turn the heater off and back on and it should begin the spark process again. Also, confirm that the tank has gas. If that doesn’t work, then a tech will need to look for the cause. Hope this helps.

  5. Steve Urbanke Avatar

    Ok I’ll start there. Are there any detailed instructions or diagrams as to accessing the sensor and wire? I have taken off the front cover but do not know where to go from there. What is the easiest way to access the sensor and wires you think are damaged? Remove the upper panel where the digital display is? Or a side panel? Or is it in the rear? I’m fairly handy but don’t want to pull things apart that don’t need to be. Thanks!

    1. Steve Urbanke Avatar

      Ok Matthew it was a lose connection at the sensor in the rear. I now have SPARK appearing on the display but it isn’t lighting. I only let it try for about 30 seconds at best. I wasn’t sure how long on initial unit startup (zero use so far, new install) it should take to fire the heater.

      1. Steve Urbanke Avatar

        So I let it attempt to light for several minutes and now get the error code Ignition Failure, no pilot sensed. Gas appears to be on, could it be a low gas flow issue? Lines are new, could I possibly make an adjustment to the gas valve to allow more flow?

    2. Matthew Simmons Avatar

      The sensor is located on the inlet side of the inlet/outlet header (where water enters the heater), in a white compression fitting. You will need to remove the side access panel above the inlet/outlet, then follow the wires as they lead to the main control panel. To access the control panel, the front door needs to be removed as does the two screws on each side of the control panel. The panel will then hinge down exposing the PC board. The temp sensor wires plug into the board near the bottom RH side.

      1. Steve Urbanke Avatar

        Thanks for the info. See my messages above, as I have resolved the sensor issue but have a new issue. Could the gas be too low?

  6. Steve Urbanke Avatar

    Hi Matthew, just installed a Raypak 156a pool heater. Getting a sensor failure code. The unit is brand new but sat in garage for a year waiting for gas line install. Was unboxed and hooked up but won’t fire. Looking for initial install startup guide or checklist. Can’t imagine what’s wrong or where to start troubleshooting.

    1. Matthew Simmons Avatar

      Chances are good that a mouse got up into the heater and chewed the sensor wires.

  7. Eric Avatar

    Hello, I have a raypak p-r336a-ep-c. The unit was already installed when I bought the home and come to find out it does not work. I going the transformer was bad and not supplying voltage to the PCB. Installed a new transformer in the unit and now I have power to the PCB and the LCD backlight turns on but there is nothing displayed. Do you think i need a new PCB or just the display? Is there any way to tell if the PCB is working? Also the unit had some burned up wiring down to the ignitor that I fixed as well is this something that happens with these units. Thanks a bunch.

    1. Matthew Simmons Avatar

      Most likely took out the sacrificial 5 amp fuse on the PCB- located next to the P6 terminal. This fuse protects the board from being shorted out. Its easily found at hardware or auto parts stores, or can be ordered under part #013733F.

      The igniter’s high tension wire is not one that is typically able to be repaired. It could have either been melted or chewed by rodents. The high tension lead is part of the igniter #002003F and should be replaced. I would also inspect all other wiring in the unit prior to replacing the 5 amp fuse and powering up the heater.

      1. Eric Avatar

        Thank you for the reply. The fuse is not blown and there is no other damage with the wiring that hasn’t been fixed. The LCD backlight lights up but there is no actual display. Is there any way to determine if the LCD is just not working and the PCB is? Thanks again.

        1. Matthew Simmons Avatar

          Okay, good. Could be just the display, but the heater should work. Problem is that, without the display, we don’t know what mode we are in and where the set points are. Try and press the mode button once and press the red up button a few times. If you hear a click and a spark, then the display is bad and the PCB is good. The display is replaceable, by removing the PCB and squeezing the two tabs on the back that hold the display to the board. If indeed this is the case, I can have one sent to you.

  8. Dave Avatar

    I have Raypac C-R406A-EN-C. When it turns on it calls for heat, says spark, the pilot lights, then opens gas for the burner and burns for 3 seconds says heating, the burner turns off then calls for spark again. This continues cycling off and on, yet is does not stay burning. I have checked all sensors and none are bad. Help please.

    1. Matthew Simmons Avatar

      Sounds fuel related. If a spring start, could be air in the line. If so, should bleed out. Is there a vent tied into the heater?

      1. Dave Avatar

        We are connected to natural gas, flame looks good when it does burn. It is indoor and has a vent.

        1. Matthew Simmons Avatar

          Is there a power vent or extractor interlocked with the heater?

  9. jerry Avatar

    I work at a rental property and they have a pool&spa area. I have two ray pac units that are giving me problems they both go into pro5 codes and say clean both pumps straners and i take them out and clean them which they both have nothing in restart them both they light and run for 2 minutes they both shut down and relight again but they both go into pro5 codes saying clean straners again but nothing in them . What can i do.

    1. Matthew Simmons Avatar

      What is the model number of the heater? The residential models only flash 3-letter codes. Do you mean it was a PRS (pressure switch open)? If so, thoroughly backwash or clean the filter; if that doesn’t work then you’ll likely have to replace pressure switch.

  10. Andres Avatar

    Hello Matthew!
    We have a Raypak M336A, and the tech came out on Monday to turn the pool on for the season. He checked the heater and it fired up right right away. But now it won’t ignite, it just sparks. It’s throwing the HL1 and GVO codes. Any help would be appreciated, Thanks!

    1. Matthew Simmons Avatar

      Andres, those codes and what are causing them are listed in the article. Have a tech come out to correct the issue if you do not think you can check the systems that are mentioned in the recommended actions.

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