Blower motor problem
#1
07-02-14, 06:53 AM
Blower motor problem
I wasn't sure where to post this but it's 90 degrees out so I thought the A/C forum would be appropriate.
About a month ago I started to here some rumbling from the blower motor. when the A/C turned on. My central system is more then 20 years old and has been trouble free(although expensive) for the 8 years I have lived in the home.
I noticed it was a bit tough to spin the fan in the housing. At that point I removed the motor to take a closer look...
This electric motor has oiling holes. No bearings and not something I have ever seen before. The company that services the unit never mentioned it and I for sure haven't oil it. After taking the motor apart I was able to clean the shaft off(there was a sticky oil residue). Mostly on the part of the shaft that extends out of the motor end plate. That would be the side that's almost impossible to oil without removing the motor. After a good cleaning and some fresh 30 oil everything is smooth again. It spun freely and no play between shaft and sleeve. I thought I dodged a bullet but 2 weeks later it started to get hard to spin again. Repeat
Here are my questions:
Is straight 30W oil correct?
Why would the oil gum up again?
How does this system supply fresh oil to the shaft and sleeve?
There is some material in there designed to hold the oil but it doesn't touch the area that needs oil. Is that my problem?
About a month ago I started to here some rumbling from the blower motor. when the A/C turned on. My central system is more then 20 years old and has been trouble free(although expensive) for the 8 years I have lived in the home.
I noticed it was a bit tough to spin the fan in the housing. At that point I removed the motor to take a closer look...
This electric motor has oiling holes. No bearings and not something I have ever seen before. The company that services the unit never mentioned it and I for sure haven't oil it. After taking the motor apart I was able to clean the shaft off(there was a sticky oil residue). Mostly on the part of the shaft that extends out of the motor end plate. That would be the side that's almost impossible to oil without removing the motor. After a good cleaning and some fresh 30 oil everything is smooth again. It spun freely and no play between shaft and sleeve. I thought I dodged a bullet but 2 weeks later it started to get hard to spin again. Repeat
Here are my questions:
Is straight 30W oil correct?
Why would the oil gum up again?
How does this system supply fresh oil to the shaft and sleeve?
There is some material in there designed to hold the oil but it doesn't touch the area that needs oil. Is that my problem?
#2
07-02-14, 07:04 AM
While I'm here and suspecting I will need a replacement soon...
What would be appropriate replacement for this? I'm not an easy time with the cross reference. Maybe because of the age.
What would be appropriate replacement for this? I'm not an easy time with the cross reference. Maybe because of the age.
#3
07-02-14, 08:19 AM
Forum Topic Moderator
It is just a standard 3 speed 1/3 horsepower 115 volt 7 amp blower motor. I would be sure the replacement does not have oil ports and is at least 7 amps.
Get a new capacitor for the new motor.
Get a new capacitor for the new motor.
#4
07-02-14, 09:05 AM
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An A/C Supply Outlet will cross-reference the motor, it needs to be as identical as possible & be a 48Y frame motor. Also, what Houston204 stated...
#5
07-02-14, 10:35 AM
Group Moderator
#6
07-02-14, 10:42 AM
Thanks for the quick answers. Looks like I joined the right forum.
Is this old motor not worth discussing? Even though the final resolution will be replacement, I'm curious how this oiling mechanism is supposed to work.
Is this old motor not worth discussing? Even though the final resolution will be replacement, I'm curious how this oiling mechanism is supposed to work.
#7
07-02-14, 10:50 AM
Thanks again for the links.
About the specs:
The number of speeds should not matter correct. My system is just on or off. I guess I would wire for high speed?
The 7amp on my old motor is what the motor draws? The new motor could be lower?
About the specs:
The number of speeds should not matter correct. My system is just on or off. I guess I would wire for high speed?
The 7amp on my old motor is what the motor draws? The new motor could be lower?
#8
07-02-14, 10:57 AM
Forum Topic Moderator
The load creates the amp draw.
If your old motor draws 6.9 amps and you install a 5 amp motor it will draw 6.9 amps and drop out.
Most gas furnaces use a lower speed for heating than for cooling.
If your old motor draws 6.9 amps and you install a 5 amp motor it will draw 6.9 amps and drop out.
Most gas furnaces use a lower speed for heating than for cooling.
#9
07-02-14, 11:04 AM
Super Moderator
Speeds may matter. Is this only for A/C? Do you know what speed it was running at before? Probably high, yes, but not always.
#12
07-02-14, 05:11 PM
How are the two speeds used. I haven't heard the fan speed change. Does heat or A/C use a different speed?
Do the speed have a big effect on register air temperature?
Do the speed have a big effect on register air temperature?
#14
07-02-14, 07:37 PM
Forum Topic Moderator
I am not an oil burner tech Gunguy and PJ help with that type of furnace but I have seen some older models have a fan limit.
This drawing illustrates how 2 speeds are used with an old gas furnace that used a fan limit...
Newer furnaces use a control board.
Looks like your black is capped and you are using blue and red speeds.
This drawing illustrates how 2 speeds are used with an old gas furnace that used a fan limit...
Newer furnaces use a control board.
Looks like your black is capped and you are using blue and red speeds.
#15
07-02-14, 09:10 PM
Super Moderator
Gunguy and PJ help with that type of furnace
#16
07-03-14, 06:41 AM
Member
Is this old motor not worth discussing? Even though the final resolution will be replacement, I'm curious how this oiling mechanism is supposed to work.
Home
The motor speeds are critical so you need to know what speeds your motor was connected for. Speaking generally because most air handler/furnaces are located under the house in a basement, cool air is harder to move up into the house than warm air and generally requires the A-C be connected to run one speed faster than the heating speed.
#17
07-03-14, 07:13 AM
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The motor speeds are critical so you need to know what speeds your motor was connected for. Speaking generally because most air handler/furnaces are located under the house in a basement, cool air is harder to move up into the house than warm air and generally requires the A-C be connected to run one speed faster than the heating speed.
In many northern climates, when the A-C is sized right & heating is still oversized, the heating blower speed can be higher than the cooling speed in order to keep the furnace temp-rise within mfg'ers specs.
In other more moderate climates cooling usually requires the higher blower speed.
#18
07-03-14, 07:18 AM
Thanks for explanation Joe. Makes some sense to me now. I still cant figure out why the oil would be gumming up in a couple weeks time. Maybe it's not just oil but a fine iron powder metal combination. It also appears I should be using a 20W oil instead of 30. Maybe its too thick. In any case thanks for the info. I just like to know.
Regarding the replacement.. I looked at the links you gave me PJ. Those sites don't list amp rating and every motor I have looked at seem to be in the 5 amp range. My local supplier cant seem to cross reference that number either.
Regarding the replacement.. I looked at the links you gave me PJ. Those sites don't list amp rating and every motor I have looked at seem to be in the 5 amp range. My local supplier cant seem to cross reference that number either.
#19
07-03-14, 12:03 PM
Member
Regarding the replacement.. I looked at the links you gave me PJ. Those sites don't list amp rating and every motor I have looked at seem to be in the 5 amp range.
#21
07-03-14, 01:42 PM
Super Moderator
I still cant figure out why the oil would be gumming up in a couple weeks time. Maybe it's not just oil but a fine iron powder metal combination.
Same thing as old cheap desk fans or wheel bearings. Take 'em apart, clean 'em up, re-lube...wow..works great...for a while.
#22
07-03-14, 03:20 PM
Forum Topic Moderator
I have replaced 20 year old motors with new blower motors that pulled more than the rated amperage this year. You are not using high speed so this may not be an issue but I would check the running amperage on the new motor and expect the amp draw to be similar to the old one.
I'd go up to half horsepower before using a 5 amp to replace a 7 amp motor but it is your decision and I do wish you the best of luck with this replacement.
I'd go up to half horsepower before using a 5 amp to replace a 7 amp motor but it is your decision and I do wish you the best of luck with this replacement.
#23
07-07-14, 09:59 AM
So the new motor and capacitor is in transit. I was looking at the wiring diagram ahead of its arrival and had a few questions. It's an inexpensive AO Smith DL1036
Electric Motors-HVAC | 5" Diameter 48 Frame | Century DL1036, Direct Drive Blower Motor - 1075 RPM 115 Volts | B185903 - GlobalIndustrial.com
I should be able to match the speeds up. They appear to be the standard colors.
Can I assume the new brown/white would go where my old white is?
Where does this new yellow go?
Rotation is determined by looking at it from the shaft end?
Electric Motors-HVAC | 5" Diameter 48 Frame | Century DL1036, Direct Drive Blower Motor - 1075 RPM 115 Volts | B185903 - GlobalIndustrial.com
I should be able to match the speeds up. They appear to be the standard colors.
Can I assume the new brown/white would go where my old white is?
Where does this new yellow go?
Rotation is determined by looking at it from the shaft end?
#24
07-07-14, 10:51 AM
Your new motor will wire up differently. The new cap will only have two wires on it ( Brown and brown/white). The Yellow will be your neutral, which will wire nut to the ( looks like you have 2 blacks and a blue coming in to the box) black wire that is going to the cap.
You bought a reversible motor is that will be easy to change.
You bought a reversible motor is that will be easy to change.
#26
07-11-14, 12:29 PM
Motor is in and purring. I didn't all the noise the old motor was pushing through the ductwork. Other then one wire it really was just a R/R procedure.
I just wanted to post one more time to say Thank You to all willing to help me out. A site like this with correct, helpful and quick answers is rare. I am glad to have found it.
I just wanted to post one more time to say Thank You to all willing to help me out. A site like this with correct, helpful and quick answers is rare. I am glad to have found it.
