Replaced thermalcouple and pilot light still won't stay lit

The system I am familiar with uses a vapour pressure type thermocouple and if the pilot remains lit the thermocouple is working as it controls the gas for the pilot and the burner at the same time from the same source - if the gas control is ok and the flow isn't prevented by the thermostat then if the pilot remains alight, there should be a flow of gas and the burner should light - unless the gas jet is blocked or something else, some other type of blockage is preventing the flow of gas to the burner...

I suggest you check the gas jet and the flow of gas to it...

It sounds like there may be an issue with the gas valve or the thermocouple on your Williams gas wall heater model # 5009622. The fact that the pilot light will not stay lit and the burners came on and went off after cleaning the thermocouple, suggests that there may be a problem with the gas valve or thermocouple. Additionally, the fact that the pilot light went off in the middle of the night, it could also be a sign of a problem with the thermocouple.
Possible causes for this issue include a malfunctioning thermocouple, a faulty gas valve, or a problem with the voltage to the gas valve.
Here are some steps you can try to fix the problem:

1. Check the thermocouple: Make sure that the thermocouple is properly installed and that the wire connections are secure. Also, make sure that the thermocouple is clean and not corroded.
2. Check the gas valve: Make sure that the gas valve is functioning properly and that it is sending gas to the pilot light.
3. Check the voltage: Make sure that the voltage to the gas valve is correct and that the wiring connections are secure.
4. Check for leaks: Make sure that there are no leaks in the gas line.
5. If the problem persists, it's best to contact a professional HVAC technician or the manufacturer for further assistance.

It's important to note that working with gas appliances can be dangerous, if you're not comfortable working with gas appliances, it's best to get it serviced by a professional.

You need a themocouple, it's a cheap $10.00 part you can get at any hardware store, you have a standing pilot light furnace like mine, if your handy and safe you can put one in easy, youtube is loaded with videos on how to do it. These other answers are wrong for your unit.

I would remove pilot light assembly and clean orifice and blow out gas line to pilot. Check to see that thermocouple is centered in pilot flame. It is possiblethat your gas valve is bad but it is also possible that you got a defective thermocouple. I would change the thermocouple again as they are much less expensive then the gas valves. The next time when you are sure you have the thernocouple mounted as close to the center of the pilot flame hold the pilot button down for several mins. If none of this works then you may have to change your gas valve.Thank you.

The blower won't turn on, until the burner is lit and builds up enough temperature to activate the blower.
If you haven't already, turn the control knob from Pilot to ON. that will activate the burner.

ths hee problem is with the thermalcoupling.that is the stick like part that is right at the pilot. replace that and every thing should be fine.

Why do you think the regulator has anything to do with the thermo-couple?if its not the thermo-couple its the flame sensor,you failed to give me the model number of the heater.when does the pilot go out.If its when the gas valve opens its the sensor.

There is a window directly above the gas control valve. Either a spring held latch or a screw off cover need to be removed to access the pilot. To light the pilot, turn the knob to pilot and hold down while lighting pilot. The pilot in straight back inside the hole about 10 inches. Use a long fireplace match or rig a wire to hold the match. Once the pilot lights, hold the control knob down for about 30 secs., if it stays lit after release, turn to "On" and operate normally.

there could be something stuck in the pilot assembly since you added a new tank to system. Check to make sure flame is hitting thermalcouple. Can you wait for a repair man to come and take pilot assembly out and clean. He will also replace thermalcouple. If you can't wait and you feel comfortable with taking pilot assembly out. Turn gas and electric off to unit then pull cover panel off. Pilot assembly is held in with two screws. Take tube off of gas valve and take off thermalcouple line off gas valve too. take out pilot assebly. Once you have it out take gas line off bottom of pilot assembly. There is a orfice in side make sure you can see through the orfice. You can also clean thermalcouple with a wire brush or sand papper. Reinstall pilot assembly make sure all fittings are tight. turn gas back on and light pilot. If everything looks good turn power on. Turn heat up run heater for a few minutes then turn heater down and let sit to see if it will stay on.

crappy pilot flame (not properly heating the thermocouple), bad thermocouple, thermocouple loose where it screws into the pilot safety valve, bad safety valve magnet.

One or more of those is the problem.

Oh...there is also a saftey switch...in case it tips over. It will also cause the pilot to not stay lit (if the switch or wires that go to i are faulty)