Evcon EB23B blower motor problems...

[amaysn]

The problem I'm having is that that blower motor is not hitting a high enough speed to blow enough air to keep the coils from freezing. In fact, even though the motor is spinning the blower fan, there is hardly any air coming out of the vents. Well, after making sure the flex duct had not come loose I called around (nobody seemed to know much about this particular unit) and was advised several times that it sounded like the blower motor was bad.

OK, so I go and get a new blower motor and install it. This motor was slightly different than the original in that it is a 3 speed motor and the original is a 4 speed. I wasn't really concerned with this as the original had only the MED-LO and HI positions connected. I connected the new motor up using the MED and HI connections. The new motor did exactly what the original did, and that is to say it wasn't blowing enough air. Needless to say, I wasn't a happy camper. While I'm standing there fuming, I heard the units cabinet door suck tight and heard the motor kick up a notch. Whalla! the unit was now working. I wasn't sure what the delay was in getting into high gear but I thought well, whatever, at least it's working.

The unit functioned properly for about a day. Now, it is doing the exact same thing again. I have now come to the conclusion that the speeds the motor turns in based on the voltage coming in. I'm guessing that for the HI speed to work, the motor needs two 120 volt connects to be activated. Is this correct? Anyhow, I broke out the volt meter and started check all the wiring I have come to a point where I think I may have found the problem.


http://i53.photobucket.com/albums/g78/a ... neb23b.jpg

In the photo, you'll see orange, black, and red wires that run up to the blower motor. The original unit had the orange wire connected to the capacitor, the black to MED-LO, and the red to HI. I wired the new motor the same way as the old motor except I connected the MED setting (3 speed) instead of MED-LO. The blue and yellow wires come off of the power supply (breaker) and they are both hot at 120 volts each. When I check the red wire (powered by the blue) I'm getting 120 volts. When I check the black wire, I not getting any juice. It would seem to me that this is where my problem lies, but I don't have any experience with this stuff so I have no idea if something else may be causing the problem. Can anybody here help me out? Could the device that all these wires are connected to be bad? What is that thing called and what's it's purpose?

Thanks,

Todd

[Robert]

Hi Todd,

Do you have a wiring diagram ?

Did you get a replacement motor designed for use in a MH ?


On the original, Blk is HI, Yell-Med Lo, Orange-transformer to run cap to motor,Red and Blu not used.


Nothing should come straight from breaker.


All wires should be from transformer to sequencer and/or blower relay to motor.



You may want to get a Tech to help get this wired right and be sure it is an acceptable motor for MH use.



Take care and best wishes,
Robert

[amaysn]

Robert,

I know it's wired correctly as it worked properly for a little more than a day. The motor did come with a wiring diagram and I installed the motor per the diagram and it worked (for a little while). The blue and yellow wires that I mentioned are coming off the breaker and are connected to the sequencer and/or blower relay. Please take a look at the picture in my first post and let me know which device these wires are connected to, relay or sequencer. Is it possibly that this device is the cause of my problems?

To kind of recap, the blower worked fine for 13 years. One day it started blowing on low speed which allows the A-coils to freeze (coils are clean and filter is new). I installed a new motor and it ran well for about a day and now it will only blow on low speed. What could be causing this?

Thanks,

Todd

[Robert]

Hi Todd,

Working for a day or a little while does not prove it is wired correctly. A back feed or a short will give same results.


Do you have a wiring diagram for the furnace ? If so, that is how it should be wired.


NOTHING should go from breaker straight to sequencer or relay,it should go through transformer or t-stat first.


That is the blower relay in the pic and may or may not be the problem.


Did you get a motor designed for mobile homes ?


Thanks,
Robert

[amaysn]

Robert,

The wiring to the transformer and the relay have not been touched for 13 years so that part of it, in my mind, is solid. I couldn't take the heat any longer and called the local guys. The motor was spinning backwards thus blowing very little air. I asked the tech what could possibly cause this as it happened first to my original blower motor, and then to the new one. I both cases the motors worked properly for a period of time, and then decided it was time to reverse rotation.

I asked the tech what would cause this, and he indicated the a bad capacitor could cause the problem. He checked my old capacitor and sure enough it was bad. He then checked the new capacitor and it is functioning properly. He could not give me a solid answer when I asked how this could have happened to the new motor. Weird.

Anyhow, it cost me $86 to get the thing working properly, which was worth every penny as it a little on the hot and muggy side here in the Phoenix area.

(Just as a heads up to readers that may be experiencing something similar to me. Check the rotation! If it's spinning backward, a capacitor could be the only thing you'd need to mess with. As it stands, I bought a blower motor that I probably didn't need to.)

Robert, I sincerely appreciate your response to my questions, and I very much appreciate having a site you can get professional advice from those in the know.

Thanks,

Todd

[Robert]

Hi Todd,

That's great and you're very welcome. Welcome to joys of electrical current flow.

Bad capacitor, power outage and quick power back on can cause it.

Few other current changes can cause things like that.


Have you powered up old motor with new run cap to see if it runs ?



Take care and best wishes,
Robert

[amaysn]

Robert,

I have not tried the old motor with the new capacitor, but it was spinning quite nicely when I removed it, albeit backwards. Live and learn on this one. I just hope that I can save someone else the hassle and unnecessary expense I experienced through the postings of my saga.

Thanks,

Todd