When I turn on the heater it turn back off

Check for error codes and service manual on following link:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

Replace gas control valve
http://waterheatertimer.org/How-to-replace-Honeywell-gas-control-valve.html

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turn gas valve to pilot hold down for 1 minute keep holdibg and light pilot hold for 2 minutes then turn to on

Treat Time Model TPC-603

Turn on light and popcorn buttons, for 2 minutes to heat up the popper's kettle.


Then turn off the popcorn button, this stops the turning gears while loading oil and popping corn.

Warning the stainless steel kettle will be hot. Might want to wear an oven mitt.
1 tablespoon of oil (I use coconut oil) and 1/3 cup of popping corn. This makes est. 6 to 8 cups of popcorn.

NOW turn on the popcorn button so the gears start turning, this turns a wire on the bottom inside the kettle to keep the kernels from sticking or burning to the bottom.

If making multi batches, during the process it states in the manual to allow it to cool 5 to 10 minutes. I normally pop 3 to 4 batches and then let it cool down.

When finished popping, turn off both the light and popcorn buttons.

turn gas knob to off, wait a minute, then turn knob to pilot. then press down on knob while lighting pilot, hold down at least 1 minute, then let the knob up slow. if it lights, then turn knob to run. if you can not light it after a few trys then the thermal coupling is bad and needs replaced. have a good day !

Is is propane or natural gas? If it is propane, i would check the supply pressure.

I have an electralog cs1205, when i turn it on, although it works , after about 10 seconds it makes a strange noise. It never did this before. Any ideas on whats wrong?

Your "bypass valve" may be wide open, which causes the heater to overheat and shut down till it cools off. Just after the filter there is a pipe, then a valve, then another pipe.Close the valve at least 1/2 way (if not more). This will force water through the heater and keep it from overheating.

A couple of things to check:

If possible, remove the pilot gas assembly and clean the gas jet and thermocouple - they can get carboned up and stop working properly. Make sure the pilot flame and deflector is aimed properly and making the thermocouple glow red hot. If the problem persists, you may want to replace the thermocouple and also check the propane regulator.

there might be timer setting or there coil is faulty.check it.