i've got a comfortec gas fireplace which uses a SIT 820 nova gas valve. i have done some troubleshooting and i think the wiring is correct and the thermopile is working properly, but the valve won't open to run the main burner, pilot works correctly however. i've called several local furnace repair places in the area, and no one deals with fireplaces. i called a local fireplace retailer, and they couldn't recommend anyone either, possibly because they're not willing to refer someone for a different manufacturer's products? as far as i can tell, comfortec no longer manufacturers gas fireplaces, so i don't know what to do. can anyone recommend a service person that can properly diagnose/fix this? should i just buy a valve and put it in? from what i've read the chances of the valve being bad are extremely slim, but i think i have eliminated all the other causes.