Need gas fireplace advice please

[Lend27]

I have a vented natural gas fireplace. No issues over the past few years until now.
I start the fireplace by flipping a standard electrical switch that controls the igniter.
The fireplace starts and all ports are lit with normal gas flow.
After about 15 minutes I noticed that parts of the burner had aflame reduction. Some of the ports had no visible flame.
I turned off the wall switch. Waited a few minutes and the same thing happened.
What can cause this gradual reduction in flame volume?
Thanks!
Len

 

[DAKSY]

Please tell us what manufacturer & model you have.

 

[Lend27]

Please tell us what manufacturer & model you have.

I found a metal tag inside the fireplace with the following info:
Mfg: Desa International
Model: VC42N

Many thanks for any info to help me resolve this issue.
Thanks!
Len

 

[DAKSY]

Thanks. Does the flame actually go completely out?

 

[Lend27]

Thanks. Does the flame actually go completely out?

No, it diminished gradually until it was about half lit.

 

[yooperdave]

Check the vent screen on the regulator to make sure it is clear of obstruction.

Also, if there was a high demand for gas from other gas appliances at the same time, this could have affected the flame of your fireplace....especially if the gas line to the fireplace was "undersized" or marginally sized.

 

[Lend27]

Check the vent screen on the regulator to make sure it is clear of obstruction.

Also, if there was a high demand for gas from other gas appliances at the same time, this could have affected the flame of your fireplace....especially if the gas line to the fireplace was "undersized" or marginally sized.

Thank you for your help. I will check the screen to make sure it is clear. Many thanks!