Abnormal Hydronic natural gas boiler burner flames?
I recently turned the boiler on for the first time this season after draining the expansion tank and it seemed very loud - almost like an F22 taking off. The area around the boiler seemed warmer than usual.
I took the access panel off to inspect. All 6 burner flames looked wrong to my untrained eyeballs. The flames have a small blue (about an inch high) part and very large orange (I would say well over 8 inches).
The boiler is an approximately 25 year old Weil-McLain CG-4-SPDN. When I had maintenance done a few years ago the technician said the boiler was in great shape and if I took care of it it could last another 10 years.
Those flames look really scary to me to be honest! I shut it down just in case - pilot set to off, turned off power, closed gas supply valve.
Posted Sep 28, 2025, 1:39 PM UTC