Comfortmaker Heat-Pump – fan not running, making buzzing nose


Old 07-17-13, 01:34 PM
Thread Starter
Join Date: May 2013
Posts: 13
Comfortmaker Heat-Pump – fan not running, making buzzing nose

House has two Comfortmaker heat-pumps, approximately 7-8 yrs
old. (New house, finished in DEC `05). Smaller unit, NHP224AKC2
heats/cools the upstairs. Never had any issues w/ either until

I got home from work, went upstairs to change, and noticed the
difference in the temp as I walked up the steps. Thermostat (a
LuxPro PSD100)(question on this at the end) showed that it was
79*, while temp was set to stay at 76*. I could hear the blower
running, and walked over to a vent – air was cool (room temp?),
but not cold. Went back downstairs, and into dining room (units
sit outside window) to check, and no, the heat-pump was not
running. (Knew it wasn’t, as you can usually hear the fans run
from anywhere in the room).

Went downstairs to check breaker-box. Nada. Went outside,
breaker on exterior box was good. No obvious clues as to any
issues. Standing next to it, I could hear a soft buzzing noise
coming from the backside of the unit, which then seemed to
ramp up, like it wanted to start, but didn’t. It then faded
after several seconds.

Doing the Google-thing, I’ve seen several other posts here
and there talking about the same issue for various units, and
the general answer seems to be that the contactor relay is
the problem.

Is there any other trouble-shooting type of test that I can
do to verify/disprove this theory? I’m no electronic Einstein,
but I did radio & vehicle electronics work for Uncle for 8
years, so I’m not a total electron dud. Is this something that
I can replace (I’ve seen several places give descriptions as
to where the relay can be accessed), or should I just call the
guys who do this on a daily basis and be done with it?

Second Q: The LuxPro stat - I've basically read that they
are the bargain-basement model of stats, and that when
you can upgrade, do so. Thoughts?
Sponsored Links
Old 07-17-13, 07:10 PM
Thread Starter
Join Date: May 2013
Posts: 13

Had a message from a neighbor who supposedly knows what he's talking
abt, but is in CA right now, so he can't come over to test this in person.

He said to turn the unit off at the outside cut-off/breaker, then go inside,
turn the thermostat off and disconnect/unplug the thermostat (the Lux-
Pro PSD100 has a removable face plate that totally powers it off when
removed). Then go back outside, turn the breaker back on for the unit,
then back inside to put the t-stat back together and turn to "COOL".

After doing this, I went outside. After the four-minute a/c safety timer
(according to the t-stat paper), the buzzing started, a click, then

He says this tells him that the fan motor is shot. Thoughts?
Old 07-17-13, 08:38 PM
Thread Starter
Join Date: May 2013
Posts: 13
Update 2

Reading a similar thread, a poster suggested giving the fan a test
spin with a stick or long screwdriver.

If it spins freely, it's probably the contactor or the capacitor.
If it's stiff, or will not spin, then yeah, the fan's a good bet.

Went outside, spun the fan w/ a long screwdriver, and it spins

Uggghhhh!!! Frustrating!
Old 07-17-13, 08:51 PM
hvactechfw's Avatar
Join Date: Jan 2011
Posts: 6,245
NO, not the fan, it is likely a power issue or a bug in the contactor. ( I literally mean an insect stuck in the contactor)
Old 07-18-13, 11:58 AM
Thread Starter
Join Date: May 2013
Posts: 13
A bug (six-legged critter) is certainly a possibility, as a handful of dead
stink-bugs fell out when I opened the access panel yesterday to look
things over. (Will have to see if there’s a way to better critter-proof this
compartment once it’s fixed.)

A neighbor mentioned that one of their units had gone down, and it had
been the capacitor (there is a single, large silver-colored unit mounted
on the unit wall next to the contactor.

Are there an ‘symptoms’ that would point towards this being the culprit,
versus the contactor? A cursory inspection (didn't remove from mount)
didn't reveal any burnt wires, or bulges. (Would a bulge be obvious, or
very slight.)
Old 07-18-13, 12:43 PM
hvactechfw's Avatar
Join Date: Jan 2011
Posts: 6,245
A buldge could be slight. Viewing the top of the capacitor the posts should all be the same height.
Old 07-23-13, 08:32 PM
Thread Starter
Join Date: May 2013
Posts: 13
Received the supposed replacement contactor - it wasn't the right
one. The one that's currently there has two thick black wires that
are secured in place by turn screws, feeding into the bottom.
The new one doesn't have any place for these to be secured.

So... while standing there, thinking long, bad words not meant for
Sunday-school, I looked at the installed contactor, and using a
dowel rod, poked the contactor. It freely springs in and out. So
it's not soldered/fried in place. I had my daughter turn on the
thermostat, and the contactor closed, but the fan didn't turn on.

Looking at the capacitor, I'm wondering if that isn't it. The top
seems to have a slight bulge, had several dead stink-bugs on top
of it, and had a yellow film around one of the posts, as can be
seen in the pic. I'm wondering if one of the bugs fried himself, and
killed the capacitor at the same time.

Pic of capacitor:
Name:  Capacitor.jpg
Views: 13576
Size:  36.9 KB
Old 07-23-13, 08:51 PM
hvactechfw's Avatar
Join Date: Jan 2011
Posts: 6,245
yep, capacitor looks bulged...............replace it.
Old 07-31-13, 03:37 PM
Thread Starter
Join Date: May 2013
Posts: 13
Thumbs up It's ALIVE!!!!

Well, part showed up (might have been able to find it locally, but my schedule
doth suck - hard, so it was just as easy), and I was able to get some daylight
(w/o rain ), and go out to swap out the capacitor.

Sure enough - the second my daughter flipped the thermostat on, the fan
kicked in and away it went.

Wifey will be glad to sleep in our bedroom tonight, versus sleeping on the
couch in the livingroom!

Thanks for listening to my issue and helping point me in the right direction!

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
Display Modes