I recently had a request to convert a InstaFlame mercury switch system to a thermocouple system. I can not find anything from company (out of business) that says you can. I am aware that some other manufacturers have issued approvals for this. Does anyone know of an written approval for InstaFlame? Also I see there are companies that will convert the burner ass. if you send it in, how can this be done with out certification? Thanks for any help.