LB White problems

[Butcher]

Its 5 years old. Green Gro 120 plus. Over the last 2 years the heat output has dropped quite a bit. Now it is giving off fumes and I am sure alot of carbonmonoxide. I have cleaned it with compressed air and cant see anything out of the ordinary. ¾ of the flame is blue and the rest bright yellow. This heater is in a green house at work. I need to get it working befor spring. I certainly wont use it till its fixed. Any sugestions?

 

[Greg_Ky]

Would you believe that they have a troubleshooting section in the owners manual?
Poke Here For The Manual

 

[JMS MN]

I use a LB White as a portable shop heater, mounted on a caster cart with 100 lb tank. Usually startup in the fall is difficult- always need to take the pilot apart and clean the orifice. Dirt or critters get in there. Good to go for the season.

 

[KIDbob]

Yellow flame means the air flow around the orfice is restricted,