I'm new to this! Help!

Are you saying the room the stove is in fills with smoke, or when it lights there is smoke in the stove when it lights? If the room fills with smoke... That's a problem!

It might have a leak or need a good cleaning.

When mine starts very little smoke comes out the vent, maybe 30 seconds. After that no smoke can be seen.

I run mine 24/7, and shut it down for a weekly cleaning.

Around me pellets are in high demand, I would try to get a few types and try them out. See what you like and order soon.

Let's address the smoke issue first. You should have NO smoke in the room, period! Sounds like the vent pipes are leaking. It clears up because of the blower creating enough air flow to overcome the leak, but this is far from acceptable. If you are not handy, call a reputable stove shop to get the venting installed correclty. It could also be a door seal, etc., but vent is most likely. If you are handy and local codes / your insurance company allow it, read the stove manual to make sure you understand venting requirements, then remove and reinstall venting. Give the stove a good cleaning (read manual) while you are at it.

Do not know about wireless tstat, but wire can be run properly by an appropriate professional. My guess is that a good installer can resolve all your problems.

I concur with Wilbur, post pic's it will be easier to help you...

The vent pipe may need to be sealed with HIGH TEMP. silicone, door seal may need to be replaced, flue needs to be cleaned or something more complicated.

I agree with Wilbur, since it's a used stove that's history history is a mystery, contacting a professional is your best bet. Just my 2 cents.

First install a CO monitor if there isn't one yet... we want to keep you and your family alive Smoke detectors and a fire extinguisher in the stove room away for the stove are important too. Edit: Surge protect it too!

What type of Harman (if free standing, should be a plate on the back of the stove with the model) A pic would likely help forum members identify too. Any identifier on the exhaust venting for maker? Does it have an OAK (outside air kit)?

Since it's a new house, not sure how strapped for cash you are ... dealer is the safest bet. If you are mechanically inclined, the harman website has many owner resources. http://www.harmanstoves.com/Owner-Resources.aspx Before trying again, figure out your model so you can download the manual and read/reread. Then you will want to clean & clean some more. The website has videos on operating and cleaning too. Then you will want to carefully review how it was installed. Some pellet venting is more inclined to leakage - depending on what you find you may want to work with what is there or start all over.

Keep us posted...