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hvacmrfixit, HVAC Technician
Category: HVAC
Satisfied Customers: 192
Experience:  30 years of commercial and residential heating and cooling installations and troubleshooting
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I have an Armstrong/Magic Chef model EG6D80DC 14-3 gas furnace

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I have an Armstrong/Magic Chef model EG6D80DC 14-3 gas furnace that appears to have been installed in 1990. The blower is the sealed/self-lubricating kind so no maintenance for me. The air-filter (HEPA fan-type) is relatively clean (only dusty, and can see light through it). I noticed last night (it is low of 7 below zero F) that after the burners lit (and stayed lit) the blower cycled on and off about 4 or 5 times before the "heating cycle" was finished. During inspection while this is occuring, I hear a "click" as the blower suddenly stops. The blower will come back on after about 20-30 seconds of "resting". Because it is very cold, the furnace is running more often, as well. Questions: 1) Is this a clear cut sign the blower is failing and replacement is needed (how long do these type blowers last), or is it more likely a switch or sensor is faulty/needs to be adjusted? 2) What else do I need to know/consider?   Thank you!
It sounds like a circulation blower control or relay is not keeping its contact points closed to keep power to the blower constant. I would look at the blower relay first and try and bypass it with a aligator clip jumper wire able to carry 20 amps and then I would jumper out that relay and see if blower kept going
Customer: replied 7 years ago.
Hi Don, I have a RoberShaw SP715A Spark Ignition System with step open valve schematic on the blower access panel. I have located the fan switch (black wire and blue wire; the limit switch has red). On the schematic, I can trace the wiring from the blower to the blower terminal box "if used", to, through, and from the junction box to the fan switch. There is a transformer connected to the junction box (if this the relay?) Electrical is not my forte, but I'm willing to try if you can tell me of those things which is considered the "relay" and if it is possible to tell me what exactly I am going to jump (I understand the basic concept, just not sure what 2 points to connect). I will definately accept so that you are paid. Bonus, if I can avoid a service call (if it really is just the relay). Thank you so much!
The relay is inside inside the elctrical box if you put 24volts to the G terminal it should pull the blower relay in and start the blower
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Jumper R to G and listen for click
Customer: replied 7 years ago.
Hi Don, OK, I've located the G and R terminals (on the outside of the terminal box by the way, Wink) and I jumped them and started the blower! Now, that means that I need to replace that relay (the item the G & R terminals are located on?) Assumming I can search/locate the part, anything I should know about replacing, or is it straightforward?
No when you jumpered the Rand G terminals that showed us the relay was good cause it started blower and kept it going. The fan controller is bad the honeywell module with th dial and pointers on it if you have one that is
Customer: replied 7 years ago.
Yes, I have a honeywell switch with the rotating silver dial with the three little pointers (the blue wire goes to fan switch side and the red wire goes to the limit switch side). OK, so I just replace that? Something I can do, or is it tricky/needs a professional? It looks simple enough....
Should beable to do your self Good Luck Don
Customer: replied 7 years ago.
Thank you so much. I'm going to accept now, hopefully it will tell me how to give you a bonus. This has been great!!!!!
Thank You!!

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