On Monday, December 28, 2020 at 11:19:29 AM UTC-5, wrote:
On 12/28/20 11:15 AM, Emptynester wrote:
I have a Majestic, direct vent, gas log fireplace model DV360 that is 16
years old. When I try to light it, the pilot usually lights quickly and
will stay lit as long as I am pushing in on the pilot knob. I have
tried holding the button anywhere between 1 to 5 minutes. I also took a
lighter to the TH and TP to try and make them hotter. The problem is,
the second I release the pushed-in pilot knob, so that I can turn it to
ON, the flame goes out. I have tried cleaning the thermocouple and
thermopile and blowing out the pilot the best I can. I can't see the
burner tube because I believe it is hidden under a burner plate/burner
housing assembly, so I can't clean that. The pilot is a nice blue and
shoots out in three directions. It just that the pilot won't stay lit
long enough so that I can turn the knob to ON. I also have a wall
switch that I normally don't turn on until after the pilot stays lit on
its own but I tried turning it on while trying to light the pilot but it
did help any. The TH, TP and Pilot look to be clean and not at all
corroded. Funny thing is, it was working fine for the last month and
then stopped lighting. Any suggestions on what to try next.

Classic symptoms of a failed thermocouple. It needs replaced. Nice that
it lasted 16 years.

+1

What are a TH and TP? TP is probably thermopile, but then he says he has
that and a thermocouple, which makes no sense to me. If the thermocouple
is bad, you can heat it until the cows come home and it won't stay lit. With
a meter he could check it. It could also be the wiring or the gas valve, but
the TC is the prime suspect.