I have a 3 1/2 year new AMANA GUIV070FX40 attic mounted system that is the furnace / air handler for an AMANA RCE42C2A condenser / compressor. The entire system, including new ducting and separate electrical circuits (220 for the compressor / 110 for the air handler) was installed by a credible / licensed contractor who has since retired... the air handler blower quit 2 days ago. Both circuits have been reset and metered for correct voltage. The compressor runs fine with good refrigerant charge and if allowed to run while the air handler blower isn't working, the condensation on the refrigerant lines will freeze in fairly short order. There is only a single flash of the diagnostic LED on the PC board in the blower compartment after cycling the power, then all LEDS go out and remain out. The air filter is brand new. The air handler blower motor is mechanically free to rotate with no noises or binding and will NOT come on by the manual switch selector or from the heat side or cool side of the thermostat. The thermostat temperature selector WILL drive the compressor to start on the cool side and WILL drive the heater burner to activate on the heat side --- the air handler blower still doesn't come on. As this blower motor is a variable speed (ECM) type, I haven't been able to find a starter or condenser. I don't see any reset button on the PC Board. Is there any way to test for voltages on the PC Board to confirm whether the Board or the Blower is at fault?

Add'l info: 110VAC to blower motor confirmed good by multi-meter... both power and control line(s) plugs removed, inspected and re-seated @ both the motor and PC Control board... 24VAC @ low-voltage xfmr confirmed by multi-meter. There is no capacitor or inductor in the blower motor 110VAC circuit.

As this blower motor is a variable speed (ECM) type

OUCH you are about to get a lesson about buying a DC motor (variable speed)

The motor and controls should be covered by a 5 year warranty. Check with the company that did the install.

Trust me you do not want to buy these parts out of pocket. They are really expensive.

If the original dealer is not available you can contact Amana/Goodman manufacturing about your situation. They should be able to tell you if it is in warranty and who to call in your area.

Thanks for the quick response. I have a written 5 year warrantee on parts and labor, but the original contractor is no more. I've been in touch with the distributor here in San Diego and was fortunate enough to have a field-experienced CSR walk me through the basic trouble shooting and then recommend me a list about 5 deep of Amana/Goodman contractors to contact locally... unfortunately, it's damned hot, they're all swamped, it was late on Friday, and I haven't been able to get a return phone call from any of them yet.

Any suggestions on additional testing to isolate the motor or controller board?

I don't know what Amana does, but another manufacturer has a motor simulator that can be connected to the control board. They also have the ability to drive the motor from another piece of test equipment.

The manufactuer's aren't very helpful in giving schematics to make life easier for those that, say, have electronics skills and could use other methods to troubleshoot.

May times swap is an easy method. It was when I troubleshot mini-computers. Swap. Find problem to module level. Send board to mfr for repair at a fixed cost. They send replacement right away if board doesn't have any physical damage.

No user serviceable parts there. It takes special test equipment and the knowledge of how to use that equipment to perform your repair. Sorry

Now if you mess with it it will void your warranty if they can tell you did.

Nothing to show my presence in there... other than having vacuumed out the dust in the airbox upstream of the filter.

I'll wait for the certified tech to get here and see if his troubleshooting leads to the same conclusion as mine... dead motor.

Sure wish it wasn't so stinking hot!!

Enjoy the read.
These are just a few.

Attached Images

ECMTech-Overview.pdf (134.6 KB, 382 views)

eginstallman.pdf (355.9 KB, 262 views)

ESPvsECM.pdf (49.8 KB, 873 views)

MeterLeads.pdf (193.4 KB, 481 views)

GREAT READING SUGGESTIONS!! Thanks for the short-course on HVAC ECM technology. I recognize that the Evergreen tech document, while it describes a 220VAC motor, can still be applied to the 110VAC system that my Amana unit utilizes... and while my low-voltage wiring harness isn't conveniently color coded to show which wires are which, I could trace each to its' origin on the PC board and derive which wire carries the Hi speed signal, low speed signal, and 24VAC common. (I do happen to have just bought brand new replacement probes for my multi-meter last week and they have the fine wire screw-on adapters.)... OR, there may be an existing pin-out diagram for my low-voltage MOLEX connecter to show which wires carry which signals...

Moving on to another topic.

Do you think that the higher operating temperatures of an attic-mounted unit should require that the coil be placed UPSTREAM of the air handler? I would certainly think that having the blower motor live in the cooler air downstream of the coil would promote longevity. FWIW, my installation is laid-out horizontally on its' right side with the return air feeding a 16x25 MERV 10 filter, followed by the air handler / furnace, then the coil and into the distribution plenum from there. I recognize that there is always the concern of moisture migration into the blower assembly from the coil, but with a horizontal layout such as mine I would think that should be a non-issue.

EDIT: Found the Pinout chart for the Ampenol 16 pin low voltage connecter.

The blower is usually before the A/C coil as a blow through assemble. Very few A/C coils are on the return side unless it is a hot water heat coil.

I do not know the restriction propertys of you filter assembly but due to the nature of these motors they are setup with the filter they are supposed to use. This is due to the readings from there air flow meter during to setup.

A filter/style change(more restrictive) can change the setting requirements.

I'm very comfortable that the filter / blower / ducting are all properly related.

I did find the connecter pinout and trouble shooting chart to isolate the issue to the motor.

All the control voltages are in place at the correct pins at both ends of the low voltage 16 conductor harness... the manual start signal is present across pins 1 and 15 following the delay relay making with the fan switch set to "on"... the motor never even twitches.

So the unit is all closed up and we're just cooking in our own juices until I can get a service call.

A valuable lesson is never to buy variable speed motors. There are other toys I have used to do the same thing with just a regular motor. Plus money wise it comes out cheaper in the long run. Infor for your next purchase someday.

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