We installed a comfort glow 50k vented propane heater for my mom. (thanks for all the help with the installation questions). The other day she said it started to roar...make a lot of noise (it does not have a fan). so she turned it down without looking at the flame and it seemed OK. I went up yesterday and there was a fair bit of yellow/orange flames. I took the burner out and cleaned it and the orifice. But neither. really seemed that dirty. The combustion area seem good....no soot. Today it happened again and this time she looked at it and said there was a lot of yellow/orange flames. She is using a 120 gal tank and it is at 30%. Up to this point (2 months) it seemed to be working OK. Because we bought it used I am wondering if I should change to orifice just to be assured it is the right size. It has been in the single digits here if weather can be a factor. She did change propane tanks a month or so ago but has had a fill with the new tank. Thanks for all your help. Julie