Just listed !
We have 1 used original manufacturer (White Rodgers) mercury flame safety switch that have been removed from a working fireplaces after we replaced the fireplaces. The manufacturing date on the parts is 95-97 and the ohms readings are great!
They tested with continuity, 0.2-0.4 ohms of resistance and a thermal dropout of around 12-20 seconds.
Our voltage tester had resistance between the leads of .1 to .2 ohms which could bring the actual resistance on this mercury switch to 0.1-0.2 ohms (good readings!).
The Mercury Flame Safety Switch is found in many older gas fireplaces made by Majestic/Insta-flame DV34, DV36, Empress, Heatn'Glo, Hunter, Napoleon, Hevac, Clare and others. Due to the hazards of Mercury, this part is no longer produced.
This may be the most cost effective way to repair your fireplace for the sale of your house!
If you would like more specific details on applicable fireplace models, please call 519-858-8924.