Hello, I’m new to this forum. Thought I would tap some of the expertise and experience this forum offers. I need suggestions on what changes should be made in order to obtain optimal performance from my newly purchased insert. All suggestions are appreciated. This is the best local deal I could find: Quadrafire Mt. Vernon AE insert. $3588.00 Quad online manufacturer rebate - 300.00 1 ton free pellets credit - 215.00 Delivery, install and setup ( with existing 3” vent ) + 150.00 Sales tax + 268.00 Fed energy rebate to claim on 2013 taxes - 300.00 --------------------- Total for everything $3191.00 Just replaced our 12 year old Country Flame “Little Rascal” insert with a new Mt. Vernon AE insert. Our house is 1362 sq ft main level with a 1362 sq ft walk out basement. We have a propane furnace with winter thermostat setting of 68 degrees. Our new insert will be used as the main level heat source. It is installed in our family room that has a 13 ft ceiling with 5 ft diameter fan. Stove date of manufacture was 3/12. Installers said that OAK was not needed. The installers used a 12 inch piece of Duravent and an adapter on the insert which connects to the existing 3 inch flex and 3 inch x 15ft of double wall pipe. All of this is installed inside a masonry flue located in the center of the house. The existing flex goes thru the fireplace damper opening that has no block off plate or insulation. The top of the flue has a flat aluminum block off plate with a storm collar on top of it. The vent pipe and rain cap terminate about 14 inches above the block off plate. Total flue length from top of insert to rain cap is 18 feet. Initial installer settings Heat out = 4, Flame height = 4, Temp diff = 2, Convect speed = Normal, Elevation (alt 1292)= Normal, Fuel type = HW pellets. Note: with these settings the air out is 200-210 degree range. EDIT 3/21/13 settings changed ; Heat out from 4 to 3, Flame height from +4 to - 5 , Fuel type from HW pellets to corn ( for longer duration between auto clean ). The installers suggested that I try using the 3 inch since its already there to see if it works ok. Will the existing 3 inch vent handle it or should I install a 4 inch? What symptoms/conditions indicate that I need to increase to the 4 inch vent ? If I go to the 4 inch should I use flex or double wall? Which brand /type suggested and where online is the most reasonable place to purchase it. I am using Somerset premium hard wood pellets that cost me $172 a ton. Have there been any software or part updates since this insert was manufactured in March 2012? Should I unplug the unit during the cooling season or should I leave it powered up? Any other hints for the operation, maintenance or cleaning on the Mt. Vernon AE insert? Again, thanks for all help, comments and advise.