Heating noise

[joe1313]

In 2008 I had a high efficency Rheem heating and cooling system installed. I ran the cooling system without a problem. This winter my heating system has started to make a noise like a machine gun. I can hear the noise from the basement, first floor and second floor. The noise usually occurs in the morning between 5 - 7 AM. Sometimes the noise occurs in the evening. It can last from 15 seconds to 1 minute and it is loud enough to wake us up. Also, it can happen several times in a row and then we will not hear it all day. I had the installer out and he has checked the system and finds nothing wrong. We taped the sound for him and he said it does not sound like anything he has heard nor is it a pipe noise. Any ideas?

[wgauci]

Could be a motor problem, there's really only two moving parts in a furnace. The main blower motor and the inducer/vent motor. If it's a higher speed sound it might be the inducer motor, it runs at around 3500rpm, it could be the wheel is off balance a little and hitting the housing or a bearing noisy. The blower runs a lot slower but can cause the same problems being off balance or a loose bracket. Take the front upper panel off, not the lower because it has a door switch that will shut the unit down. With the top door off, have someone cycle the thermostat on and see if you can pinpoint the source of the noise.

[57]

If the noise is coming from the lower part - as long as you're careful, you can remove the lower panel and "defeat" the door switch by simply pressing it in (you can do that with a refrigerator too to see if the light goes out or not) . Do not put arms, legs, pets, etc in there.

[wgauci]

57 is right, however, if you're going to manually close the doorswitch, leave the stat off first and use a piece of tape to hold the switch in and then have the stat cycled. Closing the switch with the thermostat calling can change the normal starting sequence of the furnace. Usually the furnace will bring the blower on first if the door switch is activated while the stat is calling, this simulates a power outage and prevents the furnace overheating. A normal startup cycle will usaully bring the inducer on first.

[dennism3]

Longshot...igniter problem?

[TKG26]

Could be a ignition problem or a manifold problem. ITs very likely that they never did a proper setup on the new furnace. It requires a manometer to set up a new furnace properly. They usually pretty bang on from the factory but you can never trust that. I have not seen the new RHEEMS as of yet but you may have the new versions that have a Variable/modulating input(variable not 2 stage). Its possible that your getting ruff starts from a improperly set input rate. Review the installation manual, venting can cause noises if not installed as per the instructions. This is rare but there have been certian models over the years that required funny venting practices to overcome ruff starts. Again i have not seen the new rheems they are not popular in my area yet.