I have an older hayward H250 dual thermostat, electronic ign.. When I turn it on it only runs about 3-5 seconds and shuts off. I have jumper wire the pressure switch control, the pressure switches on the headers, 3 limit switches on the front internals. I jumped them individually and then all at once, nothing helps. The inside of the tubes look like new. There was some corrasion built up externally, I cleaned them and you can see down to the burners. There is a new cartridge filter so the water flow is good. One thing I noticed before this problem the water from the heater to the pool was way hotter than normal. I am not familiar with any of the other electronics or the gas valve. Wondering if these components might be causing the problem.