Problems getting replacement gas valve for Temco GC36-3N fireplace

The igniter works, but the local gas fireplace dealer says it needs a new gas valve since the valve is not responding to the signal to turn on the gas. The dealer says the valve is not avaliable and we'll have to replace the whole unit ($4000-5000). It seems like a replacement valve even if not the original could work. Does anyone know of a solution to this problem?

what type of valve is it? maker and model

The tag on the gas line shows Dormont Mfg Co. It shows two model #s, model #20 and model #1637N. Thanks.

Dormont is the company that makes the appliance flex connector for your gas line. The model should be written right on the underside of the main control valve itself. It's most likely a Honeywell valve, and Honeywell stopped making fireplace control valves a few years ago. That being said, you might be able to find one online on ebay or something but you would need the model number off the valve.

Temco is known for their vent free but my guess would be B vent on this one. If you can post a picture we can probably at least figure out what brand of valve you have.