Blower unit hums faintly when off
#1
12-20-16, 05:23 PM
Blower unit hums faintly when off
My blower unit is in the attic.
During the Summer, the central A/C unit worked perfectly. Now, I switch to Heat in Auto mode, it will not turn on. But if switch to ON, the blower unit kicks in but no heat, temperature intake=outtake.
At the thermostat (Hunter), if I turn it OFF, the blower unit faintly hums. When I go back in the attic, what should I look for?
Thanks.
During the Summer, the central A/C unit worked perfectly. Now, I switch to Heat in Auto mode, it will not turn on. But if switch to ON, the blower unit kicks in but no heat, temperature intake=outtake.
At the thermostat (Hunter), if I turn it OFF, the blower unit faintly hums. When I go back in the attic, what should I look for?
Thanks.
#2
12-21-16, 05:52 AM
That's an electric furnace so when the stat is set to auto the heat and blower are started by the sequencer. If you have a meter test between W and common to see if the stat is sending 24vac.
BTW, the installer should be slapped for running the cables and high voltage wires right in front of the access door.
BTW, the installer should be slapped for running the cables and high voltage wires right in front of the access door.
Last edited by skaggsje; 12-21-16 at 05:56 AM. Reason: added
#3
12-23-16, 02:57 PM
I've measured RC to W/B and RC to Y/O (photo), and both shows 29.5VAC. When measured G to RC, it shows 29VAC. Everything else shows .5VAC or less (G-W/O, G-W/B
#4
12-23-16, 03:14 PM
Group Moderator
if I turn it OFF, the blower unit faintly hums
#7
12-24-16, 07:49 AM
When I removed the thermostat, the LCD stayed on while I was testing, so I'm guessing the batteries are good. But I'll test the battery when I get there this morning.
Are you talking about that 2 breaker switches on the front of the blower unit? Yes, they were both on when I was testing, although the photo shows off.
I'll check the limit switch today.
Also, according to the manual, RH is also 24V, but it's not connected. Does it need to be jumper to RC? According to the manual RC and RH should be jumpered if there is no RH wire. And the brown wire wasn't hooked up, I'm guessing it's a spare.
Are you talking about that 2 breaker switches on the front of the blower unit? Yes, they were both on when I was testing, although the photo shows off.
I'll check the limit switch today.
Also, according to the manual, RH is also 24V, but it's not connected. Does it need to be jumper to RC? According to the manual RC and RH should be jumpered if there is no RH wire. And the brown wire wasn't hooked up, I'm guessing it's a spare.
Last edited by itchibahn; 12-24-16 at 08:39 AM.
#8
12-24-16, 10:33 AM
Resolved....
I put a jumper between the RC and RH, and all working like it should.
I don't understand why the jumper was missing to start with. I had my AC guy check it out when I bought this house earlier this year. I'm wondering, because I had to call him twice a year when season changes on all both of my houses....
Thanks for all your help. I just saved $125 trip charge.
I don't understand why the jumper was missing to start with. I had my AC guy check it out when I bought this house earlier this year. I'm wondering, because I had to call him twice a year when season changes on all both of my houses....
Thanks for all your help. I just saved $125 trip charge.
#9
12-24-16, 10:43 AM
Group Moderator
Talk about psychic..... I saw your wiring on the stat and was just typing my reply.
Good find.
Good find.
#10
12-25-16, 06:13 AM
Group Moderator
According to your picture of the breakers, they are in the off position. They should be on for electric heat strips. Perhaps there is a heat pump?
He would just move the red wire from RH to RC, or vice versa, depending on the season. That sounds like a scam to get you to call for service.
I'm wondering, because I had to call him twice a year when season changes on all both of my house
