The main valve in the burner may be leaking a little--if so, the valve assembly will need to be replaced. Did the repairman detect any gas as the home inspector did? Make sure the machine is level and does not rock in any direction that might fracture or loosen the incoming gas line. Have the gas supply company check for leak.
start the dryer,go outside where it vents if you smell gas outside and only smell it inside when the dryer is running you have a bad gas valve on the dryer and most likely the valve will fail and you won't have any heat.the valve can get noisy too it will chatter when trying to let gas in if you remove the four screws that hold the door on and opposite the door screws but don't remove the door just remove the front panel you can start the dryer to see what's going on in there,i mean you have an igniter and gas coils but i've never seen a coil or igniter do this they either work or they don't so if you smell gas outside where it vents i'd go with the gas valve is bad.usually if you have bad gas coils the coils will work until they heat up and then no flame,when they cool down they will work again but i never smelled gas and the igniter will work or it doesn't not like an oven igniter they can glow but not ignite the flame and you might get a wiff of gas,i think you have a bad valve,you can get a shop vac and vac out around the burner tube and then blow it out with vac and clean out the inside of cabinet so you don't have a fire this should be done at least once a year,unplug it before you clean it out,blow out all around the gas valve sometimes a spider can make a web in there and block the orifice,write back and let me know what you find thanks and good luck.part number is WP306176 on some models you might have to get a pair of tin snips and open up the metal cover that the valve slides into they made the nut bigger for some reason and it doesn't fit through the metal cover unless you cut the cover to make hole bigger lol gotta love it.
if the vent line is blocked or lint is built up in the duct where the lint filter slides into the flame will only stay on for like 5 to 10 seconds or the gas coils are bad,when the coils are starting to fail you'll have heat for the first 10 to 15 minutes and then no heat,when the coils cool down they will work again,these are the two most common problems with a gas dryer,try removing the vent line from the back of dryer and run it to see if it heats any better if so you have a block in the vent line.or run the dryer for 15 minutes and look at the flame and see if it still ignites,if not the coils are bad.next time send the brand name and model number off of the dryer,open the door look around the opening where you put the clothes in and you'll see the model number good luck.if those two things check good you could have a bad cycling thermostat located on the blower wheel housing but i would check for a block in the pipe or lint filter duct.
are you sure the vent is open and not lugger? if it can't flow then it may be overheating and that will turn it off. check the vent and inside the dryer as there may be a blockage inside it as well.
On the face of it it sounds like the timer motor is not going and has stuck in the on position, but I would seek further advice. Someone competent and qualified should check whether the timer motor is getting any voltage and is working
It sounds like your thermal fuse blew which is very cheap and easy to replace. Unplug your dryer and gain access to the back panel. Remove the panel and locate the thermal fuse. It is usually a white piece of plastic about 1/2" wide and 1 1/2" long with two wires attached to it. (Generally located near the bottom left as your looking at it) Unplug the two wires and unscrew the screw holding it in place. Replace it with the new one and reassemble everything. Good luck!
If the motor is not burnt up you will need to change the capacitor on the motor it energizes the motor to start up and should be on the side of the motor. Presently it is single phasing or just turning over and not getting all of the power it needs.
The Videos below will cover all you need to know: Unplug Dryer and turn off gas supply before dis-assembly.
Video 1-Covers full dis-assembly and reassembly:
https://youtu.be/1eeJvqhHEYY
Video 2 is a bit more helpful in the details of proper belt mounting and alignment:
https://youtu.be/4bHOjysr5nU
Good Luck. This should make it very easy for you. Belt ribs MUST be down onto drum.
Owner's manual? Troubleshooting section. Customer service call. They are usually helpful. Wild guess, problem with the gas supply. Could be lower than normal gas pressure because of the high demand in cold weather. Could also be a similar electrical voltage lower than normal. The "brains" in appliances are too smart sometimes.
There are 2 wheels in the rear that the drum rotates on - one could be binding. The tensioner has a wheel, check it for rotation. Belt slipping? Check motor for operation - check that plastic blower isn't rubbing in its box. Dryers are easy to disassemble - check YouTube for procedure.
