Blower Wheel / Motor Replacement

Reply

  #1  
Old 12-05-19, 03:23 PM
Member
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 13
Received 0 Votes on 0 Posts
Blower Wheel / Motor Replacement

We have a heat pump that is about 16 years old with the air handler in a knee wall attic. We had some insulation work done this fall that included sealing our ducts and since then we noticed a few things:

A window in the room attached to the knee wall would rattle a lot when the blower was running. This window would occasionally rattle before the ducts were sealed, but no where near as loudly or as often.

There are areas close to some walls or corners where you can hear a low frequency rumble. It feels more like a pressure in your ears than a sound. If I partially close a door and alter airflow it reduces the rumble, so I think this is more airflow than mechanical vibration transmitted through the attic.I'm not sure if the window rattle is mechanical vibration or from whatever is causing the "pressure spots". There is definitely some vibration coming from the blower fan, and the blower also has quite a bit of dirt / mold build up (the coil looks pretty clean though).

When the technician came by for winter maintenance he said some amount of vibration in the blower fan is always going to happen and what we have was normal for a unit this age. The blower is apparently variable speed, but the previous owner had it set to always run at high speed (maybe that was needed when the ducts were less well sealed). So he set it back to only use high speed when needed. He also adjusted the risers to help improve the isolation between the unit and the attic.

With the fan running at lower speed, we don't get any window rattles and the "pressure spots" are mostly not noticeable unless you are really paying attention. However, when the motor ramps up to high speed we still have the pressure spots and occasional window rattle. The window rattle does not always happen when the blower ramps up, so I'm thinking maybe it is mechanical vibration that has been reduced.

The technician said he wouldn't bother with trying to take apart the blower wheel and cleaning it out. He wasn't sure it would help with the balance of the fan and said it's easy to make things worse if you aren't carefully with cleaning it. He suggested if would be better to just put the money towards replacing the whole blower assembly including the motor. Since it's a variable speed motor, this is fairly expensive.

One thing he didn't discuss was just replacing the blower wheel, but not the motor. If the motor is still working then only replacing the blower wheel is a lot cheaper and might address any balance issue.

I'm looking for some advice on repair or if there is any follow up I should have with the technician.

Should I just try to clean the blower and see what happens?
Would it a bad idea to replace the blower wheel and leave the original motor?
If I don't want to replace the whole assembly, should I just do nothing (and deal with the occasional rattle)?

I got the sense from the technician the amount of vibration was normal for a unit this age and wasn't likely to have a big impact on the overall life of the heat pump or blower at this point. It also wasn't clear if anything we were noticing was caused by the blower fan vibration or just the increased pressure in the ducts now that they were better sealed.
 
Sponsored Links
  #2  
Old 12-05-19, 03:27 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,143
Received 474 Votes on 444 Posts
We don't really know what you have there but if you were to do anything you could try vacuuming out the squirrel cage blower wheel. Trying to remove it from the motor could damage it. Some blower assemblies are easy to remove for servicing.
 
  #3  
Old 12-05-19, 07:12 PM
Member
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 13
Received 0 Votes on 0 Posts
The air handler is a carrier FK4DNF002000AAAA.
When I looked, I think the assembly is on two rails and held in by a plate on the end, so it hopefully isnít too too bad to remove. I should have time to look at it this weekend or next, and I can take pictures of the assembly.

From what you said, it shouldnít cause any problem to vacuum the parts of the blower wheel that are easily accessible. If the motor is attached with a standard bracket and the wheel comes of the motor easily, Iíve read itís ok to use some coil cleaner and spray the wheel down.
 
  #4  
Old 12-05-19, 09:39 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,143
Received 474 Votes on 444 Posts
Yes..... most blower assemblies just slide out of the furnace for servicing.

Usually the blower wheel(s) need to be removed to remove the motor from the frame.
You don't want to run the risk of damaging the wheel.
You can spray the wheel inside the housing. Just orient it so the liquid runs out.
 
JAHMD voted this post useful.
  #5  
Old 12-07-19, 12:49 PM
Member
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 13
Received 0 Votes on 0 Posts
I've attached some photos of the blower assembly in the HVAC. I was able to get my phone under the cage and take a picture of the blower wheel, but it's a little hard to see well.

I'm going to wipe down the wiring harness and inside of the unit with some vinegar solution.

Name:  b1.jpg
Views: 22
Size:  80.7 KB

Name:  b2.jpg
Views: 22
Size:  119.4 KB

Name:  b3.jpg
Views: 22
Size:  57.8 KB

Name:  b4.jpg
Views: 22
Size:  119.3 KB
 

Last edited by PJmax; 12-07-19 at 02:21 PM. Reason: resized pictures
  #6  
Old 12-07-19, 02:16 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,143
Received 474 Votes on 444 Posts
You've got excessive moisture there. That motor shaft looks pretty rusted and it may be impossible to get the blower wheel off even if you wanted to.

There is a lot of dust, mildew and possibly mold there. It would appear that the A/C condensation may have been running down there. Need to use bleach to kill the mold.
 
  #7  
Old 12-08-19, 09:10 AM
Member
Thread Starter
Join Date: Jan 2019
Location: USA
Posts: 13
Received 0 Votes on 0 Posts
I wasn't able to get the wheel off, so I cleaned it as well as possible with a nylon brush and vacuum cleaner (before and after pics attached). There must have been over 1/4" of hardened dirt in some places. It's all back together and while there is still some vibration at the unit, it's definitely a lot better in the living space.

It appears the condensate tray is slanted away from blower area correctly and the trap is not currently blocked. I can't say for sure because it's not cooling season now. I wouldn't be surprised if there was a problem in the past or maybe the blower at high speed was pulling water off the coil before it drained? It's in an unconditioned space, so given the amount of dirt on the blower (but not the coil), maybe it's pulling in warm / humid air through gaps in the air handler frame?

We clean the filter every 2-3 months (metal electrostatic filter) and it's never that dirty. The motor was also replaced after 2014 (that was the manufacture date) and the housing is clean / rust free. So seems like they replaced the motor and left the blower and cage at some point. I'm assuming that level of dirt on the blower must be years of build up.

Should I assume given the condition of the air handler overall and the noise level being tolerable that it's not a great investment to replace the entire blower assembly? For what I was quoted for the assembly and installing a UV light, it's getting close to what a whole new air handler would cost. Given the age of the compressor and coil, maybe just see if keeping it clean and monitoring any further mold can keep the blower going until the rest of the system gives out?
 
Attached Images   
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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