I plan to make a box out of 2x3 that covers from the old vent to the new vent and place sheet metal on the top and bottom with a cutout on the bottom piece for my new vent. There will only be 3" of space between the top and bottom sheets so I'm wondering if this will be an issue? I added pictures to help show what I am trying to do as it is rather hard to explain. [ATTACH]79759[/ATTACH]

Hi all and thanks in advance. I've seen similar posts to mine and your expert walk through gave me some confidence I could complete this with your help. Skill level zero here when it comes to electricity. I'm installing an Ecobee 3 thermostat to replace a Honeywell thermostat which ran off batteries, so no "C wire" at the thermostat. Only the Red, Green and Yellow were available as the rest were twisted around the cord and shoved back in the wall not easily accessible. I'm attaching the Ecobee to a Ruud Achiever Air handler (I have a separate boiler/ oil furnace for heat attached to a Nest Thermostat). My heating thermostat is downstairs and my AC thermostat is upstairs, so you can imagine the house is freezing downstairs in summer since the thermostat is upstairs, hence my interest in the Ecobee with remote sensor capability. I'm trying to us the Power Extender Kit (PEK) that came with the Ecobee but am not sure which wires to insert into the PEK. 1. Which is the C wire in my picture? Is it twisted to the white wire in [D] 2. If I have no heat then why is the brown connected to the white wire on the thermostat cable, which oddly is not available at the thermostat? 3. Is the safety cut-off switch wired correctly in the first place (not my handy work), in the picture. [A] yellow to thermostat/ black to safety cutoff switch and [B] reddish/orange to ?? and black to safety cutoff switch. In short what gets plugged into the PEK and what gets twisted to the terminals on the PEK? [IMG]http://imageshack.com/a/img922/2571/QRdSTV.jpg[/IMG] Thanks in advance.