Gas logs: pilot and logs burn until I shut the glass doors

I am not a service professional, but just a homeowner who has some experience with this gas log.

GAS LOG INSTRUCTIONS

Brand: Marco Gas Log (company is now out of business)
#792775, unvented gas log
Installed late 1990's when house was built


The gas is turned on and off using the key on the wall to the left of the fireplace. The gas is OFF when the key is turned as far clockwise as possible. Turn the key counterclockwise about a half turn or whole turn (180 degrees to 360 degrees) to light the pilot and turn on the log. You don't have to worry about gas coming out into the room before you light the pilot, or if the pilot goes out.

Horizontal as far clockwise as possible = OFF
Vertical ½ turn = ON

The log needs to be cleaned before using at the beginning of the season. Remove the logs, taking note of their position so you can replace them the same way. Use a toothbrush to clean the thermocouple, which looks like two little wires immediately to the right of the pilot (which looks like a metal tube that is located in the center just in front of the back log). Use a vacuum cleaner hose and duster to clean dust off all metal parts and the fire box interior. You can go ahead and replace the back log before lighting the pilot.


HOW TO LIGHT THE PILOT:

With the gas turned on with the key on the wall, find the black and white knob on the lower right of the gas log and turn it all the way to the right (clockwise) to the to the right as far as it will go, then turn it back ever so slightly to the left until you feel a little resistance (like a click that you feel rather than hear). The pilot cannot be lit when turned all the way to the right.

Push the knob in with your thumb and use your other hand to light the pilot with a long-stem lighter or match. Hold the knob in for at least 30 seconds. The thermocouple has to be hot before the pilot will stay on. Let the knob come out very slowly. Hopefully the pilot will remain lit, but if it does not, you will need to repeat the procedure until it does. Be sure to hold the knob in until the thermocouple is hot and release the knob very carefully. When the pilot stays lit, then turn the knob to the left counterclockwise until the flame stays lit and carefully place the logs back into their original position. Note: Push the knob in only when you are actually lighting the pilot, not while you are turning the knob.

Set the thermostat from Hi to Low as pictured on the knob. Once the log is lit, it should stay on until the thermostat causes it to go off. Hopefully the pilot will stay on so that the log will come back on automatically according to the setting of the thermostat (from low to high). It will be at its hottest when the knob is all the way counterclockwise.The flame will go off and on according to the temperature in the room. The pilot should stay lit even when the main flame goes out, as shown above.

Does the pilot light stay lit if you continually depress the control valve?
If the pilot light stays lit as long as you keep the valve depressed, then the problem is the thermocouple is bad. The pilot light makes enough electricity via the thermocouple to hold open the gas valve that feeds the burners. If the thermocouple fails to produce that electricity, the gas valve will shut down and switch off the gas flow to the whole unit.

One, ensure that the flame is entirely one color blue, no light blue in the center, no orange or yellow. If you replaced the thermocouple yourself, ensure you connected it to the gas valve and/or ensure that the connection to the gas valve is tight. If it is a new thermocouple you may have a gas valve issue, this is uncommon and rare. However, the valve may not be receiving the signal from the thermocouple. If the color of the flame is incorrect, turn fireplace off, and clean out the pilot tube and then relight. If none of this works, call your local trained professional. Remember you are dealing with gas, being cheap can put you in danger.

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.

Either the pilot asembly needs to cleaned or the gas valve is faulty.

The pilot light jet may have got a little bit of dirt or grit in it which is preventing it from keeping alight. Try probing the jet with a fine piece of wire to see it the blockage can be dislodged. You may have to unscrew the jet to clear it by blowing air through it. Make sure gas is turned off first before removing any parts.

The pilot light also has a thermocouple that allows gas to the pilot light while the flame is burning. If flame goes out it shuts gas off to the pilot jet. The thermocouple is bypassed by a switch during the initial ignition and once the thermocouple warms up after a minute or two of holding in the bypass switch, it should maintain the pilot. If, after cleaning, the pilot light keeps going out, it would seem that your thermocouple is faulty and needs to be replaced

The pilot light has a thermocouple that allows gas to the pilot light while the flame is burning. If flame goes out it shuts gas off to the pilot jet. It seems that your thermocouple is faulty and needs to be replaced if pilot light keeps going out

there is a small adjustment screw on the gas valve,turn it clockwise to increase pilot,if that does not work the vent cap on the gas regulator on the back of the unit could be stopped up,remove that cap ,clean out or replace unit can operate without it just fine.If you increase the pilot and it still wont stay lit replace the thermocouple

We had this problem and struggled with it for over a year. We finally hired someone to come in and service the stove he cleaned everything and blew a piece of crud from the pilot line. NO Problem for 2 years since.
He told me the pilot light should look strong pointed like a pencil not curved up like a candle. He removed the pilot and disassembleed the line and used compressed air.

The thermocoupler is no good. It's that bulb sitting in the pilot flame. when it goes out it shuts everything doen in the main valve. It has to be kept hot by the pilot, that's how it know whether or not it is safe to open the main .