Amana Air command 90

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Old 01-13-16, 08:28 PM
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Amana Air command 90

Hi Guys,

I have an old furnace, model# GHN90A35, Mfg# P9961504F.

My issue to begin with is that the blower will cycle up 3 or 4 times in a row for about 3 seconds. It will do it with both the inducer as well as the blower fan. When there is a call for heat, it runs normally. Draft inducer for 60 or so seconds, ignitor glows, flames, then blower, and it heats. I looked at the schematic, and determined that the only thing that controlled both the draft inducer and the blower fan was the combustion relay. So, I ordered a new one. It looks exactly the same, terminals are in the same positions relative to the shape of the case. So from the outside it appears to be exactly the same. Looking through the clear cover, it also appears to be the same.

So, I carefully take the wires off the old one, one by one, and place them on the new one. Start the furnace, seems to cycle up ok, then the relay starts this terrible loud buzzing. I'm not sure what to think, if there is something wrong with the relay, or if I did something wrong installing it. The only difference that I can see is the terminals are numbered differently on the new one compared to the old one. The new one is a deltrol replacement for B1373807. So, I put the old one back for now and pulled the new one.

Any help anyone can give would be great. Thanks so much.
 
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Old 01-14-16, 04:45 AM
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The terminals are often labeled as to function. They can be normally open or closed contacts or the terminals for the coil. That's what I would look at first in comparing the two.
 
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Old 01-14-16, 12:37 PM
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When the thermostat calls for heat, it does so by switching 24 VAC on to the W terminal. Whenever the W terminal is energized with 24 VAC the inducer motor should turn on and stay on.

So I'm use a multimeter to see if the thermostat is switching on the inducer motor erratically. Measure the AC voltage to the W terminal and see if the inducer motor turns on when there is 24 VAC at the W terminal and 0 volts when the inducer motor is off.
 
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Old 01-14-16, 06:58 PM
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1st - Probably not the relay as the relay is doing its job.
2nd - Sounds like replacement relay is wrong one if pins are labeled differently
3rd - Your symptoms sound like a known problem with this model.

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C6456101/C6456104
Part Number: C6456101
Sub. Part: C6456106Q
Part Name: FAN CONTROL ASSEMBLY, ON 160 DEGREES F., OFF 120 DEGREES F.

Part no longer made. Something close? Supco SLS160
 

Last edited by Astuff; 01-14-16 at 07:31 PM.
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Old 01-14-16, 07:33 PM
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And I found the diagram as well:

http://img.yumpu.com/33137280/299/1238x1600/
 

Last edited by Astuff; 01-14-16 at 09:13 PM. Reason: Changed to link to diagram
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Old 01-14-16, 07:45 PM
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The board doesn't allow for detailed diagrams to be posted. The limit is 50kb which makes diagrams unreadable.

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Old 01-15-16, 02:21 PM
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The thing that makes it difficult to check is that it's intermittent. So I'll start by checking the voltage at the W terminal, and see how it how it reacts as its cycling up. Sometimes it will happen 3 to 4 times in a row for about 5 second bursts, so if I'm prepared I with tools out, I could potentially check the terminal while it's malfunctioning. If the inducer motor runs with 0 volts at the W terminal, then would it indicate the combustion relay as faulty? The only other thing that it appears is connected to the white terminal is the pressure switch, and I would assume that's a different set of symptoms? Thanks for your help SeattlePioneer!
 
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Old 01-15-16, 02:43 PM
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Thanks so much Astuff! I'm going to go ahead and order that part and change it out. The one you indicated is only about $10 shipped, so it's worth it to check out. While I'm waiting on that part, I'm going to follow SeattlePioneer's troubleshooting. Thanks everyone for your help!
 
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Old 01-16-16, 12:45 PM
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Here's an update: I checked the W terminal during normal operation, and it seemed to work as it should. 24 VAC when the thermostat calls for heat, 0 VAC when it does not. I'm pretty sure that it is 0 VAC when the blower issue happens as well, as I was able to get down to the basement once when it was acting up, and the multimeter to it, just as it did it for the last time. It read 0 VAC, but I'd be a lot more confident if it had done it again while I was set up, just so I could be sure. A couple of things I have noticed now that I'm paying really close attention to it, it seems to always do it 3 or 4 times, it seems at least today anyhow, like it usually happens after the furnace completes a heating cycle, maybe 60-120 seconds after the furnace shuts completely down. It doesn't do it every cycle, and it seems like it happens more often when it's colder outside, such as nighttime rather than the middle of the day. That observation might be just because I'm more likely to notice it because I'm not distracted by other things.
 
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Old 01-16-16, 10:39 PM
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Sorry - the part above is not correct as it is an L160-40F and you would need a F160-40F.

Someone else had a similar issue - I have an Amana 90. Was working great until this heat season.

Try checking the voltage at the fan control switch. On side (black?) should be 120v when there is power and the other (violet?) should turn on when temp gets to 160F and go back to 0v at 120F.
 
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Old 01-17-16, 03:16 PM
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Well, crap I already ordered the L one. What's the difference between the 2 parts?

I will check the voltage of the 2 sides of the switch and post back.

Thanks!
 
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Old 01-22-16, 02:16 PM
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Ok, so I happened to be in the basement just now when the furnace started acting up. I ran to it with my multimeter, and as soon as I touched it with the probe it stopped. Then it started again, and as soon as I touched it, it stopped. When I grabbed it and wiggled it, the malfunction occurred. After the plenum cooled, touching it had no effect. So, I think it's the fan control switch. Astuff mentioned about it was actually an F160-40 not an L160-40. I don't know the specs on those parts to know what to order considering the original part seems to be long gone and F160s seem to be in short supply. Can anyone give me some help with finding a replacement or a workaround? Thanks guys!
 
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Old 01-23-16, 10:29 AM
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I'm not sure anyone besides me is still interested in this thread, but I'm going to continue to update it in case someone can use the information in the future. I was able to find an old stock F160-40 for an Amana on eBay. It's the only one I could find. There are loads of L160-40 snap discs out there however any F snap discs that I found only have a 20 degree differential. I was going to buy a F140-20 if I hadn't found this one, simply because I assumed the important thing was that the switch opened at 120 degrees to shut off the fan. Not sure if that's flawed thinking, but that's the path I was on. Thanks to everyone that helped, I wouldn't have gotten here without you.
 
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Old 01-23-16, 11:31 AM
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I'm interested in every thread. With the cold snap here and the snow... my times has been at a premium.

The difference between the F and L model.......
F = fan switch and closes on heat rise.
L = limit switch and opens on heat rise.

Your right. The replacement is 20 differential. It will work but not extract all the heat from the furnace. I'm checking for something to use there.

If I had no other choice I'd use the F140-20F switch. That means on at 140 and off at 120.
Instead of 160 on and 120 off.

All that means is you will be blowing a little bit of cooler air at the start of the cycle as the plenum isn't fully up to heat.
 
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Old 01-23-16, 12:32 PM
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Is this the one you found? How close does it look to what you have? It is mounted on a board and can't tell if there is a probe on the back.

Amana Goodman Janitrol Fan Control Assembly B14287 6 New F160 40 | eBay

Also - try removing and rotating your current one 180 degrees. It might work a bit better or worse but should be an easy thing to try.
 
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Old 01-24-16, 12:52 PM
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Yes, that's the one that I found. The one in my furnace is mounted exactly the same way on a board, same color, same everything. I did order it simply because I can't imagine finding another one anywhere. I will try rotating it as it seems to be getting worse, and I have probably 5 days before it gets here!

PJmax, thanks for explaining the difference between L and F switches, that makes a lot more sense to me now. I'm guessing they simply aren't used like this any longer, and that's why they make them with only a 20 degree differential?
 
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Old 01-24-16, 01:12 PM
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In most newer furnaces..... the fan operation is timed and controlled directly from the board instead of a sensor like you have.
 
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Old 02-01-16, 02:28 PM
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Hey guys,

One final update... My ebay purchase of the fan control switch was a winner! I received it, installed it in about 10 minutes, and the furnace has been running great! I want to thank everyone that helped me out, I couldn't have repaired it without you!
 
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Old 02-01-16, 04:38 PM
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Awesome news. Thanks for stopping back and letting us know.
 
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