Boiler making humming noise

Old 12-26-17, 06:51 AM
Thread Starter
Join Date: Nov 2013
Location: USA
Posts: 18
Likes: 0
Received 0 Likes on 0 Posts
Boiler making humming noise

Hi everyone,

I have a Beckett AFII 150, about 10 years old. Just yesterday it started to making a hi pitched humming noise, almost like a whistling noise. The thing that perplexes me the most is it only does it after itís been running for 3-4 minutes. Once it completes that cycle, shuts off and begins to run again, it will remain quiet once again for 3-4 minutes, but after that short break it will again make the noise. I do have a diagnostic stethoscope and there seems to be a clicking noise coming from the inlet side but the hum seems to be coming from the exhaust side toward the bottom of the motor.

Any my thoughts on how to even begin diagnosing this are greatly appreciated!
Old 12-27-17, 08:12 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 14,401
Received 38 Likes on 36 Posts
High pitched sounds from an oil burner are usually one of two things:
The easiest & cheapest thing to do is make sure the fuel system is clean by changing the fuel filter & pump screen. You can check the vacuum on the system by installing a gauge in an unused inlet port on the pump. If the gauge shows over 4-5 inches of vacuum & the distance from the tank to the pump isn't excessively long, you could have a restriction in the lines. (Rule of thumb: 1" of vacuum for each foot of lift & 1' for each 10 ten feet of flat run.)

The other common cause of whine is bearings in the motor.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: