As it is now, it's not accurate, so pull it out and bend the small arm that attaches the needle to the pressure tube. They are adjustable, it would have be too difficult to build them all 100% correct the first time out. As the pressure in the tube expands from heated fluid, it pulls the needle. Was it ever accurate? Has something changed?
https://www.bowtiebits.com/index.cfm used to repair them, they extended mine 20 years ago.
