Here's some info on how to correct the problem from Fantastic Vent -
http://www.fantasticvent.com/faq/kno...tly_asked.html
Q. WHY DO DOMES (lids) STICK TO THE RUBBER SEAL?
A. CAUSE: Oil or oil derivatives and Polycarbonate are not compatible, they're actually enemies. Any oil or grease on a Polycarbonate dome will cause cracks in a very short time yet Polycarbonate in the proper thickness is literally "bullet proof". Structurally, Polycarbonate remains the strongest exterior polymer available (hence, Fan-Tastic Vent lifetime warranted dome / flat lids) but, unfortunately, it's resistance to many chemicals and oil is not good.
EPDM rubber is the highest quality weather seal on the market and has been for many years. From our experience, it does not break down under severe Ultra Violet ray (UV) conditions and has remained soft and pliable for over 20 years. EPDM rubber's formula or recipe must include a lubricant for the extruding process. That lubricant is a small amount of "oil"! The amount of oil in the recipe is very slight but when subjected to heat and intense UV the rubber seal "bleeds" (a faint trace of oil develops on the surface of the seal).
The combination of Polycarbonate dome, compressed bleeding seal and sun, generates a chemical reaction resulting in a "stuck dome / lid". Historically, only a small percentage of seals extruded in the large lots we purchase bleed enough to cause this problem.
Our treating of all seals prior to packaging for 18 years with 303, a water based protectant, eliminated sticking but occasionally required additional treatment, generally, prior to storing coach. A few years ago seals treated with 303 began sticking and re-treatment didn’t correct the problem. Upon investigation, some component suppliers actually stated "EPA (Environmental Protection Agency) constraints in conjunction with dramatic cost increases and availability of essential chemicals lead to changes in the components they supplied without advanced notification”. Since then, we have used release agent (rubber manufacturer recommended), redesigned and re-tooled the seal profile, changed the adhesive we apply inside seal to hold it to the main base and finally, changed rubber suppliers!
FIX: Our current pre-treating of new vendor seals with “silicone emulsion” has proven extremely effective. Customers need only contact us toll free (800-521-029
to receive new production seals and adhesive for the correction of the aforementioned issue.