Hayward H250FDN IF Code

[mdwallace]

My heater worked flawlessly from 2009 to about 2021. I was battling first an IO code and then intermittent IF code and replaced both ignitor, fixed IO, and flame sensor with no change intermittent IF results. I suspected a heat exchanger leak due to some small about of water (not much) from the burner tube area and corroded rain shield (salt water pool). Therefore, this year I replaced the heat exchanger and still got the IF code even though I could hear the gas ignite and run for a few seconds. I then took the flame sensor and cleaned with steel wool and heater worked at least for one cycle. I replaced flame sensor again and similar results (worked for one cycle, then would not restart)
I then read about potentially some cracked solder joints on the control board (from posts in 2016). I didn't want to take this out, but finally did this evening. I did find what looked like some cracks under magnification of the flame sensor spade terminal's solder joints. While I was skeptical if I was seeing cracks, I re-soldered the spade terminal and eliminated the cracks. Put the control board back in and the heater fired up right away. I reduced the temp so the heater turned off and waited then raised the temp and the heater fired up just fine again.
So long story short, check for solder cracks at the flame sensor terminal on the control board. You can save yourself a ton of money if you have this condition.

I wish I took photos of the cracks but doubt if they would be visible without big magnification.

Just for kicks, one strange scenario I had a few years back was the IO code. I found one of the ignitor wires was chewed by possibly a mouse and was touching metal which grounded and blew a three terminal IC on the board. Easy to find on digikey and soldered that in and no issues since. I now put mothballs inside the heater as a deterrent when closing for the winter.

Hope this helps someone with Hayward heater and particularly intermittent IF code problems.

 

[ajw22]

You have gotten deeper into heater board level repairs then most people do.

 

[mdwallace]

Yeah, well trying to save money. Also an elec. eng.... Anyway, that didn't seem to solve the IF problem, I went out this morning for a test and still had the heater cycling destined for an IF code. I turned off the heater left for a few hours. I was continuing to look up flame sensing issues and found info that it could be a grounding issue. There is an article on the TFP titled "Heater Flame Sensing - Further Reading". They talk about corrosion in the grounding circuit. Since the flame sensing circuit is in the ~2-5 microamps, it wouldn't take much to disrupt this signal. The article is talking about pool heaters and furnaces that use a Fenwal (control module), but just replace the name Fenwal with control board since it performs the same function with respect to flame sensing.

So, I thought I would give it a shot. I made a green wire with two eyelets, one on each end and attached one to the flame sensor bracket and one to the chassis ground that supplies the control board through the fuse board. See photos. After I did this, turned on the heater and it is heating normally and no retry.

I will report back after tomorrow morning's startup to see if this is still the case of just another intermittent startup.

 

[mdwallace]

OK, next morning went out and still got the IF. I waited till the afternoon and heater started just fine. I had ordered new burner tubes and another flame sensor from Amazon. What I was suspecting is since the burner tubes has some rust (see picture below) due to the previous heater core leak into the area, it would coat the flame sensor with rust while the pool heater was running and with any morning condensation. This might be causing the IF. Even though I cleaned the flame sensor with steel wool, the heater would run for one heating cycle and continue to deposit rust on the flame sensor, then I would be back in the same IF condition in the morning.

By the way, the flame sensor that came from Amazon appeared to be used and not the correct one I ordered so returning it. Was supposed to be an official Hayward, but what I got was not like the picture on Amazon. See pictures below.

I decided to clean the existing flame sensor again and put in brand new burner tubes. Heater started right up with no problem. I don't know why you have to buy burner tubes in a set of 8 when my heater only takes 5. Yes, I know I could buy individual ones, but there was not much of price difference. Oh well, I have three spares now.

I'll report tomorrow if the heater comes on again in the morning and works without issue. Fingers crossed.

 

[mdwallace]

If this works, then it was still cheaper to repair than replace. New heater was quoted at $2,799. New heater core was $1000 and new burner tubes $380 (cheaper from some stores if I was willing to wait on burner tube delivery)

 

[mdwallace]

So I believe I finally have it fixed, although it cost me another ~$300 for a new ignition board. On the old ignition board, I was starting to see CE error code and then it went away after a power cycle. I could get the heater running with the old board with more or less power cycle trial and error. I had enough and replaced the ignition board. Everything has been running fine since. Automatically cycles the heat with no problem and starts up in the morning, if needed. At the end of day, it was still cheaper than a new heater ~$1,700 in parts vs a new heater at ~2,700-$3,000. I hope the ignition board has upgrades and the heater last another 12-15 years.....fingers crossed.