Furnace Blower Replacement


  #1  
Old 01-14-20, 06:14 AM
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Furnace Blower Replacement

Hello Helpers,

I think my 20-years furnace blower is going out. The model is GE 5KCP39LG V569BS, which is a 0.5 HP 1075 rpm with capacitor starter. Since this is no longer on market, I wonder if there is any suggestion as to which made and model is a direct replacement? And where to get it? I live in Central Ohio. Thanks for your suggestions.

In the last 5 years, when the blower is on during Winter, the thermostat would intermittently shut off for 1 minute, then come back on. During thermostat shut off and before back to operation, the blower and furnace would continue to run. After thermostat turns back on and complete initialization, the furnace and blower blower would stop, wait for couple minutes, and start blowing hot air again, until temperature reaches ideal target.

I found that putting in new air-filter would help reducing the frequency of this shut-off. However, starting this year, it does not help much. I don't observe this issue during summer air-conditioning time. I read somewhere that this is considered as "overloading" which means somewhere in the motor is over consuming the electricity.

Thanks
 

Last edited by sftong; 01-14-20 at 07:17 AM. Reason: clarirication
  #2  
Old 01-14-20, 09:39 AM
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The thermostat shutting off could be a limit trip.
But not much that you listed sounds like a blower issue.
You could test the capacitor.
 
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Old 01-14-20, 02:36 PM
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Sounds like the fan and limit control is turning the furnace on/off before the thermostat is satisfied. Some older ones are manually adjustable but you need the device manual to know how to set the adjustments. What did you measure to determine it was the thermostat cycling the furnace and not something else?
 
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Old 01-14-20, 09:53 PM
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As mentioned..... a thermostat that goes dead is most likely a high limit opening. That could be caused by a failing blower motor or as simple as a clogged air filter.

It's usually easier to use the model number for the furnace to locate a replacement motor.
 
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Old 01-22-20, 07:29 AM
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All right, I have replaced the Capacitor, and the issue still remain, i.e. thermostat intermittently shut off. Actually, after the blower start to run, thermostat shut off at about 1 minute 30 seconds. After 2 minutes of blank, thermostat comes back again, initialize, then blower stop. Within 30 seconds, the blower would start again, and whole cycle repeat.

Another interesting observation -- if I take away the air-filter, the thermostat would not turn off, problem solved! But the air-filter is only 2 weeks old, and it has been the exact same brand same model for years. I did notice in the past that new air-filter would alleviate this intermittent shut-off issue, but it just getting real bad this winter.

I have not tried to manually turn the blower yet. But I guess my last option is to replace the furnace blower? I live in Columbus ohio, and I do not know which reseller to contact. The model is GE 5KCP39LG V569BS, which is a 0.5 HP 1075 rpm.

Thanks
 
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Old 01-22-20, 07:36 AM
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Please stop replacing parts. We need to diagnose first. Without diagnosis nothing’s going to get fixed and your just going to keep buying parts chasing the problem.
what’s the heat rise over the heat exchanger? What air filter are you using?
 
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Old 01-22-20, 08:50 AM
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It's not a common problem but a few years ago I had a limit switch get 'weak' and it would shut down when it shouldn't. I changed the limit switch and all was fine.

I think I have a thread here someplace on that?
 
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Old 01-22-20, 09:59 AM
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I am not a pro, and have neither the tool nor knowledge to measure the heat rise over heat exchanger.

Guess it's time to pay big bucks for a pro?

 
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Old 01-22-20, 10:34 AM
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If you don’t have the tools or ability to check various parts and operations, it’s likely a better investment to have a pro check things out then replace random parts.
What air filter are you using?
 
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Old 01-22-20, 11:09 AM
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It's a merv 10 filter, bought from Amazon https://www.amazon.com/gp/product/B004PVVC8O/

Now think about it, my wife bought this package 1st time this year. It was usually MERV 8 in the past, which was associated with less tripped-off of the thermostat.

Guess this means I should get a new motor to give the air a little extra push?

Thanks
 

Last edited by sftong; 01-22-20 at 11:12 AM. Reason: clarified
  #11  
Old 01-22-20, 11:27 AM
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Get a less restrictive air filter. The filter could be undersized or even the return duct could be too small.
 
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Old 01-23-20, 08:20 AM
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Thanks Roughneck.

Since we already have this MERV 10 and it causes the temperature limit switch to turn off the furnace, I am thinking to use it during the summer air-conditioning time. However, is the risk high that the cooling coil could freeze and break in the heat exchanger, due to lower air-flow? I have seen the HVAC guy put in the aluminium cooling coil right above the furnace gas burner, which I presume it's the Heat Exchanger section.
 
 

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