Installing and troubleshooting a heater that is still under warranty without proper licensing can forfeit your warranty under the manufacturer’s terms and conditions. If your heater is out of warranty, sometimes, it’s simply cheaper to do it yourself. If you yourself in this scenario, this blog article is for you. In this blog article, we cover the most common swimming pool heater problems a pool owner might encounter and remedies to fix the issue.
My Heater Won’t Ignite
One of the most common problems with pool heaters is it failing to ignite.
Is your heater turned ON and the temperature set correctly?
- Ensure that the thermostat is set to a higher temperature than the current water temperature.
Is your pump running with a clean filter and basket?
- Inspect the pump and filter and clean if necessary.
Make sure that the pilot is lit (millivolt heaters).
- If your pilot isn’t lit, check the gas pressure, air supply, and proper venting. Make sure the pilot tube is intact and not clogged. For MV heaters, if the pilot won’t stay lit, check the output on the thermocouple.
Is the gas supply valve in the ON position?
- Without gas, the heater won’t operate. If the supply valve is OFF, turn it ON.
Are the plumbing and filter valves open?
- Make sure to keep your valves open as to not prevent the water flow.
Low Water Flow
In order for a heater to operate smoothly and efficiently, it’s important that pool system maintains a consistent flow of water. Manufacturers equip swimming pool heaters with pressure sensors. These special sensors monitor and detect changes in water flow. For example, in some cases, you will see a “Low Water Flow” warning pop up on your heater’s LCD screen. Or, you might notice your heater isn’t pushing out as much warm water as it should or used to. Honestly, this is a very common occurrence. If you are experiencing low water flow, or your heater won’t start, ask yourself the following questions:
Have you cleaned your filter lately?
- Monitor your PSI reading on your filter’s pressure gauge. If the PSI is too high, clean your filter.
- Increasing pressure goes hand in hand with the decrease of water flow.
Is your pump basket dirty?
- Check your pump’s strainer basket. Remove the basket and remove the debris with a hose.
- Ensure the pump basket and lid are in good conditions. No cracks.
Do you have too many water features operating at once?
- Your pool pump only moves a certain number of GPMs, therefore, too many water features can dramatically decrease your water flow.
- If possible, replace the motor with a larger one.
- Close water features, or alternate them, until the pool heats to the desired temperature.
Defective Pressure Sensor/switch (Most Common)
- The purpose of the pressure switch is to ensure that water is flowing through the unit before it allows the heater to turn on.
- The pool pump must be ON and your filter clean for the switch to close and allow voltage to pass through.
- Test the voltage reading on the pressure switch with a multimeter.
- Replace the pressure switch if necessary
Are you using the low settings on your variable speed pump?
- For operation, heaters require a minimum GPM flow. If you are running your variable speed pump on the low setting, make sure you meet the minimum GPMs for your heater.
Pool Heater Turns ON and OFF (Cycles)
If your swimming pool heater is cycling ON and OFF, it is an early indication that the electrical connection or power supply is experiencing issues. However, it isn’t ALWAYS the case. There are other factors that can actively contribute to your heater’s ON and OFF cycles.
Is your pool water chemistry consistently and accurately balanced?
- Poor water chemistry is one of the leading causes of equipment failure, especially pool heaters.
- Test your water before adjusting your chemical levels. If unsure, please refer to the heater’s manual for the recommended chemical levels.
Have you inspected the pressure sensor, thermal regulator, and/or the high limit switch?
- Inspect these parts for corrosion, scaling, and/or any electrolysis issues.
- If the pressure sensor, thermal regulator, or high limit switch is faulty, corroded, or defective- replace it.
Have you cleaned your filter?
- A dirty filter can cause low pressure and as a result, cause the heater’s pressure switch to turn OFF. A dirty filter can prevent a heater from firing and it can also cause your heater to shut off before warming the water to the desired temperature.
When’s the last time you have inspected and cleaned the heat exchanger?
- Deterioration of the heat exchanger can impact your heater’s operation. Inspect your heat exchanger for chemical or sanitizer damage.
Pool Heater Isn’t Heating
Sometimes, your pool heater ignites but doesn’t reach the desired temperature. Or, maybe your heater isn’t generating heat at all. Both situations are very common.
Inspect your temperature sensor.
- Make sure you have installed the temperature sensor correctly and it is in good condition.
Double check your thermostat settings
- Set your thermostat to a higher temperature.
Did you properly size your pool heater?
- If your heater is undersized, it will have problems heating your pool up. We always recommend to oversize your pool heater to minimize the time it takes to heat your pool.
Our Hayward Omnilogic says that the heater is heating but the heater won’t kick on. The pool temp is reading at 82 and the heater is set to 88. Any thoughts on what the issue could be?
Can I light my pilot light to test it before I turn on the pump and get water flowing through the pool heater. I have a Pintar Minimax 250. Older model…….probably around 20 years old.
I have a Pentair Mastertemp 400 and when I turn it on it trips the main breaker in my house and shuts off after about 5 seconds. Could this be because of low flow?
The Mastertemp has an alert or error code display on the control module. Have you had a chance to view it? If so, what code is it flashing?
I have a 20-year-old Hayward Swim Pro H150 pool heater. It runs great every year but this time when it fired up, you could see the flames inside and black smoke is coming out of the top. Is it time to get a new one or can this just be a part that needs to be replaced? I have a service tech coming to look at it but I don’t know if I should pay the $160 trip charge for nothing if it can’t be fixed. Thank you.
The heater could just be dirty and in need of a thorough cleaning. If you are seeing black smoke, and the flame is not burning clean (the flame is orange, not blue) a dirty heater is my first hunch. I’d fork out the money for the service call.
Hello,
I have a pentair Sta Rite 333 gas heater. It works great except it sounds like a subwoofer when it’s on. I can hear it from inside the house.
Any ideas? It does heat the pool great otherwise.
If you experience a rumbling/grumbling sound from the heater, you probably need to have the burner tray cleaned. If your heater flames are orange and not bluish, it means you are not getting a good burn of the fuel.
i have a hayward gas heater sw150 not heating the water at all everything is running fine getting gas water pressure all good no codes someone tells me it a bypass
I have a Jandy Pool Heater, model LT400N-L (made 6-2006) and it stopped working. Red light on Pressure Switch. I put it on the to-do list for about 2 years. Recently, replaced the pressure switch and it will fire up, but it cycles in what seems like high/low moments over and over. Water is flowing, fan comes on, I see the flame in the tiny peep hole. Fan comes on 35 seconds, then a cycle of warm air comes out and fan gets louder for 15 seconds, then warm air ends and fan seems to drop a speed. During the warm air/ high fan cycles, the water does pump in hot into the spa. I have the Jandy PDA and the AquaLink RS cabinet–water temp registers spa=74 on the PDA and I have the temp set to reach target 102. The high limit switches are in excellent condition visibly but I still bypassed them with a jumper, no change. I found the diagnostic flow chart online, tested all the voltages, all was well until step 7=”After approximately 30 to 40 seconds of igniter heat up, is there 24 VAC at VAL terminal of the Ignition Control?” For as long as I kept the probe on that terminal, the brown wire (VAL) on the ignition control module measured 0. Could it be the ICM? Before I gamble on such an expensive part, can I bypass/jump/test this brown terminal, or do you see something else I’ve missed?
We left our pool heater on last night and forgot to remove the pump timer switch so the pump turned off but the heater was still on. It had an error code of “low flow”. Now the heater ignites and runs but makes a low pitched whining noise andcthe water does not feel very warm out of the jets. Did we ruin our new 2019 jandy gas heater?
Where the whining began after the heater fired dry; that could be scale that developed inside the exchanger while the heater ran with superheated water going through the exchanger. In this case, is the heater below the level of the pool, and if so, how many feet below? If the heater is located more than 5 feet below the body of water, then the atmospheric weight of the water is enough to close the contacts of the pressure switch allowing the heater to fire. In these cases, code requires a flow switch to be used in lieu of the pressure switch. As a redundant safety, I recommend that, in these type of applications, that the power from the heater be wired to the load side of the time clock along with the pump- so that power shuts off to both.
Can you tell where the sound is coming from within the heater? Is it coming from the gas line, gas valve or the exchanger? There might be multiple problem areas.
Just purchased a new natural gas Hayward H350FD, also purchased a propane conversion kit to change it over. I got everything installed and the heater starts and fires up and the shuts off and gives a IF code. I checked when it was dark outside so i could see the flame glowing in the sight glass. Don’t know what to do now……?????
My first thought/question, why didn’t you buy a propane heater to begin with? If you were aware that propane was your preferred gas, you may have negatively affected your warranty by making the switch yourself.
I suggest you call a professional to come take a look if you are having any issues. This is a troubleshooting guide Hayward uses, but again, I suggest you call a professional.
Hey I do understand, but I got a big discount on the heater itself. Anyway, regarding the code, I believe that it is a gas line issue, I will be installing a new gas line and regulator and see of that helps.
I have a Ruud spa heater and it fires ups but then says “fan delay” and turns off within 10 seconds
Hello Matt,
I have a Jandy LXI 400 natural gas heater and recently I started spa and heater and all seemed to be good, but after waiting almost 45 minutes the spa never started to heat up and the heater appeared to be running fine with no faults.
Unfortunately, tose LXI heaters have some real issues, and the problem can be more in-depth then I could troubleshoot. I suggest contacting Zodiac (Jandy) to see if they can walk you through a troubleshoot or can have a tech come out.
Hi,
Thank you in advance for any insight you may have on this. Our pool/spa heater wasn’t heating the spa much. Temperature would rise a little, but it wasn’t getting the water hot. Water from the jets didn’t feel much warmer than the spa water. The heater seemed to be getting hot. Our home warranty replaced the heater today (Hayward 400FDP) after 2 hours the water went from 56 to 78. Water from the jets still doesn’t seem any warmer than the spa water. Outside temperature mid 60’s. It used to heat to 100 in about a half hour. There is plenty of propane.
If it was just installed and you are having issues, you should get the company back out there to take a look at the heater. You may want to check that only the spa is being heated, not a combination of the pool and spa. There could be an issue with the gas line not being big enough which is an issue if you upped the size of the heater from the old one. The latter should definitely be checked by a professional.
I have a Raypak 280 swim pool heater and the temp is set 32 Deg. I can see the the pilot light and the gas being lit but it goes off just after few seconds. The pump pressure is good, i can see the water travelling into the heater through the clear check valve. the gas tap is on at all times. have anyone came across this fault ever.
This is symptomatic of low gas pressure or low water flow. If propane, check the level of fuel in the tank. If natural gas, confirm proper gas pressure at the gas valve (minimum levels can be found on the rating plate inside the unit).
Is there a fault indicated on the control panel?
If water flow is insufficient (less than 1.6 lps), then it could be tripping one of the overtemp sensors. Confirm proper water flow through the heat exchanger. Clean and/or backwash the filter. Empty all baskets. If not, it could be scale or blockage inside the exchanger.
Hello I have a Rheem 8350 pool heater. The pool heater states it’s 104 and keeps shutting off but the actual temperature is 84 what could be wrong.
It could be a bad temp sensor. But, that model uses two sensors with different Ohm ranges. There is a way to check that the PC board is reading the right range.
The best thing to do is to call the heat pump service line 800-375-7378, and they can walk you through the process. You will need to be at the unit and will need serial number and date of installation handy.
MiniMaxNT LNSeries. Pool pump on – it fires up fine within 15 seconds or so. Pool features off and pool return is on full. I have the heater set to 102 and it is starting at 60. It only heats up to about 62 after an hour. The water coming out of the spa return is just warm, not hot.
This is our guide for Pentair MiniMax NT Heater Error Codes. Is your heater lashing an error code? If so, that would be important info to know. This is the Owner’s Manual for the Pentair Minimax NT LN Series.
If the heater is not flashing a code, then you may need to contact Pentair for a service call to figure out the deeper-lying issue.
I have a Hayward h400idl and i first had a fire on the board, so i replaced it, then it wasn’t getting gas so i replaced the gas valve. Then i was getting the ao code, so i replaced the blower. It worked for one night on the hot tub, and then i got the ao code again. I sent it back, got a new one and new hoses and the blower vacuum switch and the vent pressure switch. I got ao code quick and i noticed the blower was really hot. The hoses looked like they moght be melting. Any ideas? TIA
I guess you have no idea.
Sorry, your question got skipped, fell behind because of vacation. In the interim, I would have suggested contacting the manufacturer for their expertise.
As for the blower being hot, that is pretty standard because it is sitting over the heat exchanger and next to the exhaust stack. You may want to make sure you have the circular insulation mat that sits between the blower’s flange and the stack. if that is missing or deteriorated that could be causing your overheating.
did you ever find out the problem with excessive heat blower barbs?
Hi Matt
I have a raypak PCO 430 gas heater. Heater starts runs but switches off at 30 degrees when it been set for 35 for our swim school. Heater was off for two weeks in our holiday period,
Any help with solving this issue would be greatly appreciated. You are a knowledgeable guy.
Cheers and thanks again
Adin
When the heater is shutting off, is it giving a service code on the display? Could be shutting off due to low water flow to the heater “O”. Or if F2, F3, or F4 is coming up then it is a sensor problem. Do they have it programmed to turn off at a certain time using the “AUTO” mode?
I’m having exactly the same problem. I can’t get the unit out of Auto mode. I just want to manually set the temp and the pool warm up to that temperature.
As you can see, I was asked them about error codes to which they did not answer. So I’ll try with you. Were there any error codes?
I have a Pentair Master temp 200 heater. The temp reading started fluctuating quickly from 81 to 85. The setpoint is 84. The heater burner kicks on and off following the temp fluctuations. I replaced the thermistor and cleaned the control board and connections. Same results. Is this a control board issue?
Follow these troubleshooting instructions for the MasterTemp on page 38, hopefully, you can verify if the board is good through those steps.
What does Option valve light on mean on a Hayward pro logic control panel mean?
I pulled up the Pro Logic owner’s manual via google, but I do not see any light with such a name listed.
My heater (pentair )is reading 94-96 degrees ( did read 104 earlier this afternoon but came down to 94 when I turned unit off then back on again) but is set at 80. To touch it is obviously not at 94. When I raised the temps to 95 the heater did click on. Can u tell me what the problem is.
Just had my heater begin starting and stopping. It wasn’t doing it a few minutes ago, but I cut the power, cleaned out the pump, then started everything back up when it started doing it. It got a little splashed from the filter being open when I cut the pump back on. Any thoughts on what could be going on? Did the water from the filter possibly cause a short of some kind?
What is the make-model of the heater? The heater model number would work to.
Hello
My Sta Rite SN0004NA heater turns on, fires up, heats water for 3 minutes and turns off. Then in 10 minutes it does it again.
The filters are clean
The pump basket is clean
good water flow,
had gas checked – that is fine.
Any ideas?
Hi Beth, you may want to check your pressure switch.
Hi Matt, any advice on my question from June 4 about the Jandy Lite 2 (Model #: LG175N)?
Any advice greatly appreciated!
Chris
Matt- I bought a house with a smaller in-ground pool (approx 15′ x 30′, 3.5′ shallow, 5′ deep) that has a gas powered Raypak P-R206A-EN-C. Heater is 9 years old, worked great last summer- would heat the pool to temp in an hour or so, with very warm- almost hot- water pumped into the pool. This summer the heater fires up fine, plenty of heat coming from the unit, but water pumping in is luke-warm, and takes hours to get to 85, where it peaks out. The pool service company I inherited looked at it (unannounced while no one was home) and said the heater “couldn’t be working better” and that if I wanted more heat, they could install a bigger heater. This does not sound right… thoughts?
A lot depends on what region in which the heater is located, as to the heat rise per hour. In the Midwest this year- without a cover- it has been difficult to achieve a decent heat rise- until a couple of days ago.
Pool heaters do not modulate, they are either on or off- delivering a blended delta T of about 6- 8 degrees (inlet pipe to outlet pipe) no matter the pool or air temperature. I’m guessing that the service company confirmed that the heater was not shutting off intermittently and was running at a proper delta T. If so, then the heater is doing what it can do, though the water may feel different coming from the return- depending on the pool temp. A solar cover would help with heat loss, but that model heater is very capable of recovering heat loss in that size pool. Hope this helps.