Jandy Pool Heater Won’t Ignite [7 Easy Solutions]

The major reasons behind Jandy pool heater won’t ignite include a clogged pool filter, a bad flame sensor, and a defective igniter. Disabled safety switches, faulty pilot settings, and valve malfunction are also some of the leading causes of the Jandy pool heater not turning on. 

When you find your Jandy pool heater not igniting, make sure there have no obstacles to the water and gas flow on the pool heater. Resetting the pool heater functions into factory default settings is effective troubleshooting in this case.

However, go through our below discussion to get a complete guide for this problem.

Jandy Pool Heater Won’t Ignite [7 Easy Solutions]

Throughout this comprehensive article, we have discussed all the trouble points that occur in the ignition problem of the Jandy pool heater. Also, you will get well-proven procedures that will assist you in fixing the issue surely.

Note: You can also read how to fix Raypak pool heater ignition failure problem.

1. Clogged Pool Filter

If your Jandy pool heater is not turning on, there would be a higher possibility of a clogged filter. When the water filter gets blocked with debris, it restricts the normal water flow.

For that, the heater fails to startup in the normal way. Also, because of a clogged water filter, there may create low gas pressure in the heater. 

When the gas pressure becomes down than normal, the pressure switch activates. Right after then, the heater stopped working.

Anyway, now you have to make sure that your pool filter is completely cleaned and unblocked. Follow our below-suggested instructions if are in confusion about how to clean clogged pool water filters:


  • Before starting, the cleaning procedures, shut off the pump to stop the flow of water.
  • Turn the air relief valve counterclockwise and release the filter pressure.
  • Now, locate the locking knob of the filter cartridge counter. Turn the knob clockwise to loosen the filter head.
  • Once removing the cover, take the cartridge and lift it straight up to disconnect it from the filter. Or, you may directly clean the cartridge filter without lifting it.
  • For that, you have to put the cartridge filter on your lawn or any hard surface. Then start rinsing the filter using the hose.
  • Continuously spray it up and down until the filter gets cleaned. Once complete the cleaned, reassemble the filter as in the previous way. Make sure you have securely set the filter.

2. Bad Flame Sensor

A defective flame sensor is one of the major reasons behind the ignition failure of the Jandy pool heater. Because of a bad flame sensor, there creates a flame rectification issue, and the heater fails to ignite.

A flame sensor of a pool furnace is a safety component. The function of a flame sensor is to detect and confirm whether the flame is burning or not.

On the basis of this, the gas valve opens and ignites the heater. Anyway, as it is made of metal, there may build up rust over it and restrict its normal operation.

In some cases, there may create cracks that prevent proper sensing of the flame. This time, we will examine the flame sensor of your pool heater:


  • Disconnect your pool heater from the power connection first.
  • The flame sensor is quite easy to access. Just disconnect the front panel of the pool heater by unscrewing all the attached screws.
  • You will see a rod-shaped flame sensor there.
  • Now, disconnect the wires and screws connected to the sensor. Carefully remove the sensor.
  • Check out the sensor. If you will find any visible cracks and damage over there, replace the bad sensor.

3. Defective Igniter

The igniter is an essential component of a pool heater. It plays a big role in the ignition system. But most of the igniter goes bad, and for that, it fails to operate properly.

From the expert suggestion, if the furnace won’t turn on, there is a high chance of a defective igniter.

However, after checking the sensor and filter, it is time to concentrate on the igniter. Follow the below instructions:


  • First of all, buy a quality hot surface igniter and replacement parts that match your Jandy pool heater model.
  • Now, disconnect the heater from the power source.
  • Inspect the igniter and the connected wiring.
  • Remove the bad igniter and replace it with the fresh new one. Now, check if your heater is turning on.

4. Reset The Jandy Pool Heater

In most cases, only a hard reset on the heater system proves well in the case of not turning on. Sometimes, the ignition of the pool heater goes lockout, when it fails to ignite after 2 or 3 attempts. This time, the heater needs a hard reset.  

How Ro Reset The Jandy Pool Heater

A hard reset will easily eliminate the lockout and the heater will come on. However, without any delay, let’s start the resetting procedures:


  • There has a reset button on the Jandy pool heater. Locate the button from behind the control panel.
  • Put on the cover of the control panel. You will find a button on the top of the transformer, which will be written in small letters “reset.”
  • Move the reset switch to the “W” position for about 5 seconds. This will hard reset your heater and set it into factory default settings.

5. Disabled Safety Switches

Disabled safety switches are another most likely cause of your pool heater problem. In every pool heater, there is a configured safety circuit as a control loop.

Two safety switches are connected to this circuit board, and that must be enabled while you are trying to ignite your heater. The pressure switch is the first switch on this circuit, which function is to control the flow of water into the unit.

The other essential elements are high-limit switches, the thermostat switch, and the fusible link. This time, you will have to check the complete circuit:


  • Take a power meter and measure the voltage of the pressure switch.
  • In the case of a defective switch, you may bypass it using a jumper wire. It will build up a strong contract at both terminals on the switch.
  • Jumpstart the heater by connecting a jumpstart cable with the metal terminals on the heater switch. The heater should come on.
  • Check out the high-limit switches, the thermostat switch, and the fusible link in the same way. Bypass them if needed.

6. Faulty Pilot

If your Jandy lite2 pool heater won’t turn on, there probably have a bad pilot generator. For several reasons, the pilot tube stops working.

It may be clogged with debris, or there may have been rust built over it. In some cases, insects block the pilot tube, and that restricts the normal gas glow. However, in this troubleshooting period, we have to check out the pilot generator of your pool heater.


  • Take a multi-meter and connect it with the pilot generator leads 
  • Measure the DC volts of the pilot. There should have about 500 mV.
  • But if you find less than 400 mV, disconnect the pilot generator leads from the gas valve.
  • Now connect the lead directly to the multi-meter.
  • If the generator leads have a voltage reading of less than 600 mV, be sure it is defective. Replace the pilot.  

7. Malfunctioning Of The Valves

One of the most common reasons behind pool heater ignition failure is the malfunction of the valve.

So, while checking the other essential parts, we can’t ignore the valves and the valve’s settings. Either the valves are closed and blocked by debris. Anyway, troubleshoot the valves issue by following the below instructions:


  • Check out the gas valve first. Ensure that the gas valve is completely open. Otherwise, it will restrict the flow of gas.
  • Then investigate the visible wires of the gas valve as well. If you notice any types of cuts and damage, replace the wires.
  • Measure the voltage of the valve. Read through your model manual for a better understanding.
  • If needed, replace the faulty gas valve. And make sure each of the valves is adjusted in the correct order.


What does the FLO error code mean on the pool heater?

FLO mainly indicates a restriction in the water flows from the filter pump to the heat pump. For the low water flow, the heat pump will turn off by itself. When the heat pump gets the water flowing from the pump filter, it will turn on again. 

Why does my pool heater say HP?

HP basically indicates opened high refrigerant pressure shut off. The high refrigerant pressure switch shuts off the compressor if there builds overheating on the pool heater. Restriction on water flow is highly responsible for this.  

Wrapping Thoughts

Hopefully, now you know all the possible reasons for the Jandy pool heater not igniting issue. Troubleshooting this issue will not seem so hard as long as you will follow the above comprehensive guide.

We can expect that you will easily troubleshoot this ignition failure issue by following our guide.

But if you have any queries regarding this guide, don’t hesitate to let us know through comments. We will reply to you as soon as possible.

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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