NG Fireplace takes too long to start

[headviking]

My fireplace was built when my house was built. 20 years ago.
The problem is even with my pilot light is alway lit, whenever I flip the wall switch it sometimes takes up to 15 minutes to light. If I have run it the night before it may take as little as 2 minutes.

Thanks for any help or advice.

 

[DAKSY]

It could be a bad thermopile, or it could be a bad wall switch.
Remove the switch from the wall, disconnect the wires & touch them together.
If the fireplace lights immediately, replace the wall switch.
If it doesn't get a multimeter & set it to read millivolts.
Touch the leads to the screws on the valve terminal block labelled TH-TP & TP.
Tell us what reading you get on the pilot with the wall switch off.
Then turn the wall switch on & take another reading.
What did you get that time?

 

[headviking]

It could be a bad thermopile, or it could be a bad wall switch.
Remove the switch from the wall, disconnect the wires & touch them together.
If the fireplace lights immediately, replace the wall switch.
If it doesn't get a multimeter & set it to read millivolts.
Touch the leads to the screws on the valve terminal block labelled TH-TP & TP.
Tell us what reading you get on the pilot with the wall switch off.
Then turn the wall switch on & take another reading.
What did you get that time?

Out on vacation now. Will check on my return.
Thanks for the quick reply.
I will report my finding.