strange issue with Hayward heater

[Construx]

hi all,

I have a Hayward 400 heater that has been doing strange things since installation. It works perfectly right up to 89 degrees. At any temp over 89 it randomly locks out (display goes to "LO" ) and takes several minutes and/or several power-off resets in order to get it to fire. I've bumped up the high-limit temp and ran it in both spa and pool mode, but nothing seems to make a difference. Any ideas?

 

[ps0303]

What model and when was it installed?

 

[Construx]

It's an H-400, installed last season. It otherwise works perfectly and after it shuts down and I fiddle with it, it fires right up to spa temperatures without issue. It's just something that happens at the 89-90 degree mark. It was also possible that it has something to do with run-time (I tend to fire it up from the same original pool temp so it runs about the same amount of time each time it happens) but it seems more likely that it's related to temperature.

 

[ps0303]

Well if its still under warranty I'd get a tech out to look at it. If it's not under warranty it sound like one of the limits my be going.

 

[MHarvey86]

Do you have an automation system? If so, are the two low voltage wires run inside the same conduit as the high voltage lines? If yes, then there could be some interference. Shot in the dark on this one - best to have a professional check out this issue in person

 

[Hayward Pool]

Let's talk about the LO code. The LO code normally means inadequate water flow. You will always see this when the pump shuts off, the filter get very dirty or something or someone has redirected flow. Once the pressure switch detects inadequate Flow, the heater will shut down to protect itself.

 

[Construx]

Best I can tell, the only change to the system is the temperature. It will run flawlessly right up to around 89 degrees, then it will give me a hard time with a "lo" code. After fighting with it for 10 min or so, it will re-fire and run flawlessly again right up to set-point. Changing flow, increasing backpressure, etc, have no effect. It dies at 89 degrees like clockwork.