Motor | Coleman Presidential III Model # 7970A856

[Vlaj]

Hi.

Coleman Presidential III Model # 7970A856 furnace w. A/C, 20 years old, mobile home.

My motor went out the other day and I had it replaced.

Now, when it runs, It makes a humming noise like it's not balanced and when it starts it makes a noise too. Also, I felt the motor and it's very hot.

My questions are:

1. What should I do about the noises? Balance motor or blower wheel?
2. Should I replace the motor mounts and/or motor clamp?
3. Is the motor supposed to get very hot? Even the black electrical power wires near the base of
the motor are hot.
4. When running, the furnace seems to be much loader. Normal?
5. Could you please tell me the correct motor # I should be using with the A/C furnace?
I should add that the A/C was added after the purchase of the home. And it's a Bryant
A/C..if that makes any difference?

Motor 1/8 HP 1100 RPM 8.2 Amps, 7966-3119
or
Motor 1/2 HP 1075 RPM 7.0 Amps, 7670-3239

Also, the scroll has # 7970-590 stamped on it. I wonder if you need to change it with difference size motors?

Thanks

[Robert]

Hi,

If there is a problem with the replacement, have you contacted whoever did the replacement ?

If it was a DIY replacement, have you contacted who you purchased it from ?

Did you by chance purchase the motor from us ?


What is the p/n of the motor you installed and also what is p/n of the old motor ?


The 7970-590 blower assembly is for heat only.



Thanks,
Robert

[Vlaj]

Thanks Robert.

I had it replaced my a family friend who does heating and cooling although, they don't usually work on mobile homes so he is not familiar with them. We had to call him since the motor went out at night and he came over in the morning. I would have changed it if I had the time. He said it is an OEM and bigger motor? I know it has 2 black wires and just a green ground and one speed. The # 1469-220P motor was a 2 speed but he said I did not need 2 speed with the new motor. Also, I don't see any capacitor on the scroll.

I called him to come back because of the noise. He came Friday and moved the motor wheel a bit which helped a little then tighten things down. He did mentioned that the platform was cheap and that's part of the noise although, it was not there the past 10 years. I asked him to look into new bushings and new motor wheel? To me it sound like it's not balanced.

He said he would call me Monday and tell me what he found about those parts.

I just want to know what I should suggest?

10 years ago I did replace it with a motor # 1469-220P although, as you mentioned the scroll # 7970-590 is for heat only so all along I have had the wrong scroll. Is that a problem?

[Robert]

Hi,

When you add a/c , you have to upgrade the blower assembly unless it came a/c ready. Yours did not.

The new motor would have to be designed for use in a mobile home duct system and the blower wheel would have to match the motor.

You CAN use a one speed motor, but I do not recommend it. Best having 2 speeds, one for heat and other for cooling.

The platform being cheap and reason for noise is ludicrous. As you said, it wasn't there for past 10 years.

The 7966-311P is the one speed motor.



Thanks,
Robert

[Robert]

How many tons is your a/c unit ?


Thanks,
Robert

[Vlaj]

It's a 2 ton I think.

It says:
Bryant
MOD# 593CJ030-B
R-22
5 lbs, 60 hz
HP 1/10
208/230
Hi PSI 450, kPa 3102
Lo PSI 210, kPa 1448
Compressor: 208/230
1 PH, 60 Hz
13.7 RLA, 75.0 LRA

So, what should I humbly suggest to the guy who installed this motor or what should I do now?

[Robert]

Hi,

You can use the one speed motor IF it is designed for mobile home units and correct for your furnace as for as specs..

Next, need to know if you have correct size wheel as well for heating and cooling.

IF you can get correct motor and wheel to fit inside the housing, then that is all that would have been needed.

If not, the a new blower assembly would have been needed.

My recommendation would have been and still is a new blower assembly with a 2 speed motor, same motor you had.


As for what to say to him, that is up to you. Since it was installed and used, probably stuck with it.

Will be your decision what to do from here.

What motor did he install and what size is the blower wheel ?

IF you had the correct blower wheel, then you could/should have replaced with same motor.

IF not, then easiest would have been new assembly with same motor and correct wheel.



Thanks,
Robert

[Robert]

Hi,

Here is the correct and best assembly which should have been installed when a/c was added:

Blower Assembly # 7900 - 6061/A on left side of this page:

http://www.mobilehomerepair.com/ColemanAC.html



Thanks,
Robert

[Vlaj]

I think he installed this one 7966-311P. I saw the picture of this online and it looks just like it.

The blower wheel I measured and looks like this one:
667252
10x7x1/2

[Robert]

Hi,

10 X 7 X 1/2 is correct size wheel. All you needed was the same motor you had and a new run capacitor.

In my above reply was the whole assembly. Here is the parts if bought independently:

Blower Motor # 024 - 35603 - 000

Run Capacitor # 024 - 20063 - 700

Blower Wheel # 1472 - 2751


I personally would not accept a one speed motor when I had the correct 2 speed motor already and an exact replacement was readily available.


Take care and best wishes,
Robert

[Vlaj]

So I could just keep the 10x7 blower wheel even though you mentioned that the 7970-590 blower assembly is for heat only?

Also, where is the Run Capacitor? My scroll does not have any Capacitor.

I see your point although, the motor he took out with 2 speed was only hooked up to run as one speed since I installed it before.

[Robert]

Hi,

10 X 7 X 1/2 is correct size wheel . Sometimes it will be same as heat and cool assembly, but not always. This time it is.


The 1468 - 220P motor should have had a run cap. The 7966 - 311p does not need one.


2 speeds is best and will work much better than one speed.

You need a higher speed for cooling than heating and with one speed, it is set more toward cooling for that reason.

Then, when heating, it blows too fast and cools furnace too much, air is not as warm coming out.



Thanks,
Robert

[Vlaj]

The 1468-220P did not have a run capacitor when I purchased it. I just installed it and left the other wires unattached. That means it was running at low speed the past 10 years?

Do you have a diagram how to hook up the 2 speed motor on this unit?

And, Is there a way to balance the motor and wheel when it's replaced?

Thanks a lot for your effort and time!

Vlaj

PS. This new motor installed 7966-311P, really kicks out a lot of power. It seems to be heating my master bedroom near the lake much faster with more heat (this room is always cold in winter).

Although, you mentioned that the 2 speed is best and will work much better than one speed.
And that the I need a higher speed for cooling than heating and with one speed, it is set more toward cooling for that reason. Then, when heating, it blows too fast and cools furnace too much, air is not as warm coming out.

So, why is the house warming up faster especially the back room if this high speed is supposed to be cooling the hot air too much?

[Robert]

Hi,

The motor doesn't come with a run capacitor, you have to ask for it and purchase it separately.

It requires the use of a run capacitor to operate.

All motors have wiring diagrams on the side sticker of motor.

There is no balancing for motor. The wheels have balance weights on them and if they become out of balance, you have to replace the wheel.


Cool air is heavier and requires more velocity to move it through the ducts. A one speed motor will be set to that higher speed for the cooling and when you switch to heat, the higher speed will cool down furnace more and work against the heat more so than the slower speed.

IF you are satisfied with one speed, stick with it.


Thanks,
Robert

[Vlaj]

Just so I learn...

If I needed a run capacitor for my old 1468-220P, then why did it work when I installed it before?

Also, why wouldn't I need a run capacitor for the motor 7966-311p, I have in there now?

Oh, forgot to ask...I felt the motor after it ran the other day, it was hot to the touch and the black wires where warm but not too hot. Is this normal? I just wonder if those black electrical wires will ever overheat since there are right there near the heat console.