Hi. I have a Hayward H350FDN pool heater that is Doing this: • Turn on and Temp at 65 • On for 3 1/2 min then shuts down • Restarts and then on for 5 min, shuts down • Restarts and then on for 2 min, shuts down • Restarts and then on for 8 min, shuts down • Temp 66 • Restarts and then on for 10 min, shuts down • Restarts and then on for 2 1/2 min, shuts down • Restarts and then on for 1 min, shuts down • Restarts and then on for 1 min, shuts down • Restarts and then on for 10 sec, shuts down • Restarts and then on for 40 sec, shuts down • 1F error code I just replaced the heat exchanger prior to this happening. Any ideas???
I’ve contacted our Hayward tech rep to get his opinion. I’ll reply back to this thread as soon as I get a response.
Below is the response we received from Hayward.
There are two most likely causes. Low or poor water flow to or through the heater is one possibility. The other would be an ignition issue, such as the flame sensor damage or dirty reporting that there is no flame or a weak flame which would shut the unit down, but since there was a call for heat (they didn’t state the set-point) the unit would try to fire again.
If it’s just a matter of poor water flow then increasing the speed of the pump or opening valves allowing flow to the heater (and out of the heater) will resolve the situation.
If it’s the flame sensor then either it’s dirty, faulty, or it may be telling the truth. If there is a poor flame due to poor air-to-gas mix then it will take a gas appliance technician with a manometer to check and adjust the gas valve. If it is a poor flame due to poor air flow or gas flow into the combustion chamber then cleaning the jets (burner orifices) and maybe foreign matter blocking air flow in and out of the combustion chamber would solve this.
I notice that they’d replaced the heat exchanger recently. Nobody goes through that big job and expense unless an exchanger is leaking. If leaking then it is possible that pool water sprayed onto the tops of the burner tubes and that may have left chemical residue. That residue blocks the flame sensor from receiving an electrical charge to ground (provided by the burner tubes) through the flame, which is how the unit determines the quality of the flame. If this were the case then the unit would fire, may run briefly (minutes) then shut down and try to fire again. After three attempts to get and keep a strong, efficient flame then fails, an “IF” code would be reported indicating ignition failure.