I've pretty much decided to abandon the use of the Cat on my Insert. The Regency I2500 is basically an I2450 that has a Cat that slides over the flue opening. My experience based on the probe temps is that engaging the cat, causes an immediate reduction in the draft, the probe temps rise but come back down after a short period. I don't seem to get any extension on the burn times and my stove top temps don't go up. It looks to me that the cat's sole purpose is to burn enough residual partials to get the stove to qualify for the Tax Credit.
On top of needing to remember to engage/disengage the cat, I have had some trouble with it getting stuck or being difficult to engage when the stove is hot. Since it does not seem to be adding any heat going into the room, it seems to be more trouble than it is worth. I will probably engage it periodically to burn off anything that might accumulate on it, but I think I am done with using it on a daily basis.
On top of needing to remember to engage/disengage the cat, I have had some trouble with it getting stuck or being difficult to engage when the stove is hot. Since it does not seem to be adding any heat going into the room, it seems to be more trouble than it is worth. I will probably engage it periodically to burn off anything that might accumulate on it, but I think I am done with using it on a daily basis.