I just got this hot air furnace installed

Goodman gks90904cxae‏

Its got LP for gas

The heat coming out is not as hot as my older one and I think the fan speed is way too high

Anyone know how to set the fan speed on this particular model?

Goodman

Model - gks90904cxae‏

Thanks

All the information you need is included in the install instructions. In may cases especially with a variable speed blower you will need a special tool to set the correct speed to match the design of the duct work. Ask the company that sold you the furnace and did your install to make the adjustments for you or tell them to return the install directions so you can read how to do it yourself.