LP furnace noise


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Old 12-14-00, 01:24 PM
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Lately, when the Rheem LP furnace burners light, I can here a loud hum coming from the burner area. This is a new thing and seems to only happen when outside temp is < 15F.
I can eliminate the hum by turning the off/pilot/on control knob part way from on toward pilot which slightly reduces the burner flame and stops the noise. Noise can't be heard after blower starts, whether it quits or is cover by blower noise I don't know. It doesn't do this every cycle. Furnace is working fine otherwise. Any thoughts. TIA
 
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Old 12-14-00, 02:12 PM
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Hi:Steve

The condition is caused by a lean fuel mixture.
The burners are getting too much air through the air shutters located on the burner tubes.

The shutters are on the back end of the burner tubes. These shutters often have an adjustable slide held in place with a small phillips screw. You'll see them on the tubes <venturi's> where they slip on to the orifice jets extending out of the gas manifold tube.

By SLIGHTLY closing them, the noise <Howl> will stop. Use CAUTION!!! Closing them too much will cause the burners to burn yellow! A condition you do not want to cause.

If your not too sure of what to do, I would highly suggest you have a professional adjust the burners input air ratio. Ask your propane gas retailer if they will provide this service for a small fee or free. Many will as a way to help you, their customer.
 
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Old 12-14-00, 03:55 PM
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ok, Tom, did that. Quiet so far. Whats a good LP flame supposed to look like? How much blue? Orange? Yellow? How tall the flame? Your help greatly appreciated. Steve
 
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Old 12-14-00, 07:44 PM
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Hi:Steve

Glad you had success with the air shutter adjustments.

Do not be concerned about an ORANGE color in the flame. This is only dust burning and it can be repeated any time, simply by a tap on the furnace or a burner. No cause for alarm.

The color of the flame must be blue. All BLUE at the top of the flames. There must not be any YELLOW on the flame tips nor in the body of the flames.

There isn't any difference between a natural gas flame and a propane gas flame. Both must burn BLUE without any trace of YELLOW.

The burner flames, when adjusted correctly, will be extending directly upwards, will not have any trace of YELLOW and the flame will not be floating downwards nor around.


The beginning <innner cone> part of the flames MUST remain on the burner extending upwards. The flames should not be lifting up off the burners.

The inner cone will appear a light blue in color. The outer cone will appear a darker blue. This can be easily noticed if you have a full view up the firebox. If not, take a good look at any burner flame on the stove.

FYI:
The cap letters in this reply or any other reply I post, are NOT meant to as shouting at you or anyone else. I only use them to add emphasis to important detail.
 
 

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