AC noise

[Shortest Straw]

Rear whisper quiet ac is not so quiet. It is making a rattling sound which can be heard much better in the return vents than the flow vents. Unit is working just fine otherwise. Anyone have an idea where to start looking for the cause?

 

[Divotf15]

I would use an inspection mirror or bore scope to look in the intake dust for something obvious. If nothing obvious, I would open up the rooftop unit. I think it is 4 screws to remove lid, then pull the styrofoam straight up and it will reveal the plenum. Guaranteed you will see something in there you don't like. If u go in there, wrap up all the wiring and tape it off the bottom. If you ever get water in there and the cat5 plug gets wet, thermostat will read 32 degrees inside and won't turn on ac. Drying the plug out fixes that if u ever have that. Ducting will be terrible in ac unit. You will want to seal the the duct work at the onnection

 

[TravelTiger]

It could be the unit is not tight to to rig? At Goshen they looked at ours, and must have tightened it down because the bedroom one is much quieter since then.


Sent from my iPhone using Tapatalk

 

[donr827]

Do not over tighten the bolts. Some one else will join in and give you the correct way to tighten the bolts if necessary.
Don

 

[jbeletti]

Mike - I could hear a rattling in the ceiling when my front AC unit was on. I recently removed the covers for all 3 AC units and found I did not care for how all the wiring up there was managed.

I carefully coiled/bundled all wiring and tie-wrapped it all up so that none of it was still laying in the plenum. Pretty sure this is what was rattling but have not confirmed. Also, and trust me on this, take a small shop vac up top with you. I vacuumed out all areas I could reach up top on all 3 AC units. I even worked the hose as far into the ductwork from up top, trying to suck as much debris made by cutting the vent holes.

A month later, I had to remove the AC cover on one unit again - guess what, more debris got sucked up to it. Vacuumed again. I think I'm winning now


Note: To haul a small shop vac up top, I tied the extension cord to the handle of the vac, then heaved the cord up top. Then up top, I simply used the cord to pull the small vac up and lower it back down. Worked well.

While I haven't done so, I think to haul small tools and supplies to the roof, a rope on the handle of a 5 gal bucket could also be tossed up to the roof to haul up / down the bucket-o-stuff

 

[Shortest Straw]

Mike - I could hear a rattling in the ceiling when my front AC unit was on. I recently removed the covers for all 3 AC units and found I did not care for how all the wiring up there was managed.

I carefully coiled/bundled all wiring and tie-wrapped it all up so that none of it was still laying in the plenum. Pretty sure this is what was rattling but have not confirmed. Also, and trust me on this, take a small shop vac up top with you. I vacuumed out all areas I could reach up top on all 3 AC units. I even worked the hose as far into the ductwork from up top, trying to suck as much debris made by cutting the vent holes.

A month later, I had to remove the AC cover on one unit again - guess what, more debris got sucked up to it. Vacuumed again. I think I'm winning now


Note: To haul a small shop vac up top, I tied the extension cord to the handle of the vac, then heaved the cord up top. Then up top, I simply used the cord to pull the small vac up and lower it back down. Worked well.

While I haven't done so, I think to haul small tools and supplies to the roof, a rope on the handle of a 5 gal bucket could also be tossed up to the roof to haul up / down the bucket-o-stuff

I did the same with the wiring yesterday and now the rattle went away. I did not do the shop vac yet as the honey do list has more important items to complete first. I have a long 20 ft dog cable I use when i need tools up top. I clip one end to my wash bucket handle and walk up the ladder with the other. Shimmy the bucket up with the cable. My bucket will hold everything I need. The wife is working on strengthening her pitching arm for the stuff I forget...

 

[Lou_and_Bette]

Mike, glad Jim’s suggestion of tying the wires together worked for you. I have been following this thread ready to jump in with what my problem was when my a/c started “rattling.” FYI, your’s and others who follow the forum, when my front a/c (not whisper quiet) started making a terrible rattling noise I pulled the cover and discovered the short piece of copper tubing that sticks straight up (the one that is crimped and sealed) was vibrating and hitting the cover...slight repositioning stopped the noise. Small thing making a huge noise that made me think the a/c was going to be FUBAR very soon.