No blower when on A/C

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  #1  
Old 03-10-19, 11:21 AM
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No blower when on A/C

Heating works fine. When I switch it to A/C the thermostat clicks once to call for it and then clicks again for I donít know why. When this happens the outdoor unit comes on but no inside blower. I have pretty old GE furnace that I replaced a relay in about a year ago, I wanna say Iíve had problems ever since.
 
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  #2  
Old 03-10-19, 11:48 AM
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Welcome to the forums.

The first click you hear should be the blower coming on.
The second click is the A/C compressor which is delayed 3-5 minutes to stop short cycling.
The furnace uses a heat control to start the blower. The A/C uses a relay.

Sounds like you wired the relay incorrectly.
 
  #3  
Old 03-10-19, 12:22 PM
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Maybe

Itís a 2 or 3 pole relay, Iíll check it out.
 
  #4  
Old 03-10-19, 12:25 PM
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You could always post a few pictures..... How-to-insert-pictures.
 
  #5  
Old 03-10-19, 05:24 PM
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Tried

I canít get photos to upload on my phone I tried multiple times. The relay is a Tyco Electronics model S87R-1079-1 /
24v 50/60Hz / WG24X113 / B309140P01 / 60 LRA,12 FLA / 1HP, 125VAC / 48LRA, 8FLA / 2HP, 250VAC

The Furnace is a b1982 115w General Electric BLD080E936B1

Inside the little electric box where where the relay is located there is a green wire hanging there, if itís the g wire I have no idea where it belongs on the relay. Iím gonna work more on getting a photo.
 
  #6  
Old 03-10-19, 05:29 PM
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Hi, do you have wires connected to the coil terminals on that relay, does the Tstat have a fan ON function ,will the fan run when the Tstat is in that position?
Geo
 
  #7  
Old 03-10-19, 05:53 PM
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Yes the relay has wires hooked to the terminals and no the fan will not run in the on position.
 
  #8  
Old 03-10-19, 10:36 PM
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If you only have a phone.... try selecting "desktop site" if available.
 
  #9  
Old 03-10-19, 10:58 PM
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Hope the res is ok, in one of those there is that green wire I was talking about. Not sure if thatís the G wire for fan or not.

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Last edited by PJmax; 03-11-19 at 04:16 PM. Reason: reoriented/resized/enhanced pictures
  #10  
Old 03-10-19, 11:36 PM
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The pictures are on there side, they need to be rotated to the right.
 
  #11  
Old 03-11-19, 05:06 AM
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Hi, with the Tstat set to fan ON do you have 24VAC on the relay across the coil terminals?
Geo
 
  #12  
Old 03-11-19, 09:06 AM
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Yes across the coil terminals there’s 28VAC.
 
  #13  
Old 03-11-19, 03:26 PM
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I took a piece of jumper wire and with the Tstat face plate off I touched between the 24v and the G wire and the fan never came on so I know it’s in the furnace. I can’t find the problem though.
 
  #14  
Old 03-11-19, 04:17 PM
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Schematics

These are the schematics for my furnace
 
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  #15  
Old 03-11-19, 04:23 PM
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Ok..... redid the pictures.

There should be five wires on the relay. Two low voltage and three high voltage.
The two low voltage terminals should go to C (one side of the transformer) and G.
You said with FAN ON you have 24v on the coil. That's good.

The other three terminals should be labeled COM, NO, NC.
COM should have one of the fan speed wires on it.
NO (normally open) should have 120vAC on it.
NC (normally closed) should go to the fan/limit switch.

Added diagram from member link......
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Last edited by PJmax; 03-11-19 at 04:38 PM.
  #16  
Old 03-11-19, 05:49 PM
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1-C or com has a yellow wire that runs back to the transformer and a grey wire that runs up to the door sensor or safety kill switch where the blower is located.

2-NC runs to the bottom left input on the fan switch.

3-NO runs up to the 3rd spot on that wire connector and then connect to a black wire for the fan motor.

The top low voltage is G the green wire and the bottom is blue, they are both running back to the thermostat.
 
  #17  
Old 03-11-19, 05:59 PM
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On 2-NC the leg has what looks like discoloration in the metal like it got hot. 3-NO has the same. 1-C does not.
 
  #18  
Old 03-11-19, 06:40 PM
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Looking at the diagram.... when the fan is in auto mode.... the relay is at rest so the C to NC connection is made. That means the blower runs at a reduced speed when the furnace heats up.
Just to confirm..... this is correct ?

When you put the stat in FAN ON..... the C to NO connection is made. I colored the diagram blue because that's what the diagram showed. Black would be the full speed wire. So basically when the relay is closed you are sending 120v directly to the black/high speed winding. If this is not working...... try a different color on the motor. You could even swap red and black for testing.
 
  #19  
Old 03-11-19, 06:48 PM
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The blower doesn’t come on at all until the furnace heats up that coil switch and turns it on so no there is no low speed while heating up.
 
  #20  
Old 03-11-19, 06:51 PM
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Now I'm lost..... when the furnace heats up..... the blower runs..... correct ?
 
  #21  
Old 03-11-19, 07:17 PM
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No it does not, the furnace heats up that fan switch and then it clicks turning on the blower, it’s a 2 to 3 minute warm up with no fan. I made a video but it’s to large.
 
  #22  
Old 03-11-19, 07:20 PM
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That's how it's supposed to work. That is a fan/limit switch. It monitors the temperature and turns the blower on when the plenum gets up to heat. It has nothing to do with the relay.
 
  #23  
Old 03-11-19, 07:21 PM
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Just to confirm you meant swap the black to the red on the fan motor for testing right?
 
  #24  
Old 03-11-19, 07:22 PM
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Yes...... that is correct. We know the red winding is working. We're not sure about the black.
 
  #25  
Old 03-11-19, 07:37 PM
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So I’ve got the red hooked up on the fan off of the relay NO, what exactly am I testing because you said you were lost but I’ve been kinda lost.
 
  #26  
Old 03-11-19, 07:51 PM
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Ok..... put the stat to FAN ON. That will or should send 120v to that red wire.
 
  #27  
Old 03-11-19, 08:02 PM
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Ok so nothing happened when I switched it to fan on heat or cool.
 
  #28  
Old 03-11-19, 08:08 PM
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When you switched the stat to FAN ON..... the relay closed..... correct ?
If yes..... the relay is bad. The NO contact has a problem.

You've confirmed the NC contact is ok because you get the blower when the furnace heats up.
 
  #29  
Old 03-11-19, 08:51 PM
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So I heard the relay click loudly when it was suppose to kick the fan on. It did nothing.
 
  #30  
Old 03-12-19, 12:36 PM
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Trying to find one of those is fun! Trying to find one at a good price that is.
 
  #31  
Old 03-12-19, 12:47 PM
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It can be any 24vAC DPST relay. Do you want a link to Amazon ?

Do a search for 90-293.......... 90-293 at Amazon
90-370 is another one.
 
  #32  
Old 03-12-19, 01:24 PM
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Thanks
You wouldn’t happen to have any kind of literature or video on how to hook that up for that model would you.
 
  #33  
Old 03-12-19, 01:27 PM
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Hi, the connections are shown on the side of the relay, 2 coil terminals and C, NC/NO
Geo
 
  #34  
Old 03-12-19, 01:29 PM
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10-4 thanks a lot guys I greatly appreciate it.
 
  #35  
Old 03-12-19, 01:49 PM
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Let me know which relay you ordered and I'll write it into the diagram.
 
  #36  
Old 03-12-19, 03:49 PM
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Emerson 90-293Q Enclosed Fan Relay https://www.amazon.com/dp/B000H5Y1SA..._.AdICbXZ9KPJJ
 
  #37  
Old 03-12-19, 04:05 PM
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The pinout.......................

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  #38  
Old 03-12-19, 04:47 PM
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Awesome I’ll let you guys know how it goes, it will be here Thursday!
 
  #39  
Old 03-15-19, 10:38 AM
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Still haven’t gotten my package from amazon, I’ve never had problems with prime before!
 
  #40  
Old 03-15-19, 10:46 AM
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Are you affected by their new "once a week" delivery for prime members ?
 
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