Bard QH602, QH243, QH482, QH422 Troubleshooting GE ECM Motors CONT’D, Replacing ECM Control Module

Page 31

TROUBLESHOOTING GE ECM™ MOTORS CONT’D.

Replacing ECM Control Module

To replace the control module for the GE variable-speed indoor blower motor you need to take the following steps:

1.You MUST have the correct replacement module. The controls are factory programmed for specific operating modes. Even though they look alike, different modules may have completely different functionality.

USING THE WRONG CONTROL MODULE VOIDS ALL PRODUCT WARRANTIES AND MAY PRODUCE UNEXPECTED RESULTS.

2.Begin by removing AC power from the furnace or air handler being serviced. DO NOT WORK ON THE MOTOR WITH AC POWER APPLIED. To avoid electric shock from the motor’s capacitors, disconnect power and wait at least 5 minutes before opening motor.

3.It is usually not necessary to remove the motor from the blower assembly. However, it is recommended that the whole blower assembly, with the motor, be removed from the furnace/air handler. (Follow the manufacturer’s procedures). Unplug the two cable connectors to the motor. There are latches on each connector. DO NOT PULL ON THE WIRES. The plugs remove easily when properly released.

4.Locate the two standard ¼" hex head bolts at the rear of the control housing (at the back end of the control opposite the shaft end). Refer to Figure 23. Remove these two bolts from the motor and control assembly while holding the motor in a way that will prevent the motor or control from falling when the bolts are removed. If an ECM2.0 control is being replaced (recognized by an aluminum casting rather that a deep-drawn black steel can housing the electronics), remove only the hex-head bolts. DO NOT REMOVE THE TORX-HEAD SCREWS.

5.The control module is now free of mechanical attachment to the motor endshield but is still connected by a plug and three wires inside the control. Carefully rotate the control to gain access to the plug at the control end of the wires. With thumb and forefinger, reach the latch holding the plug to the control and release it by squeezing the latch tab and the opposite side of the connector plug and gently pulling the plug out of the connector socket in the control. DO NOT PULL ON THE WIRES. GRIP THE PLUG ONLY.

6.The control module is now completely detached from the motor. Verify with a standard ohmmeter that the resistance from each motor lead (in the motor plug just removed) to the motor shell is >100K ohms. Refer to Figure 24. (Measure to unpainted motor end plate.) If any motor lead fails this test, do not proceed to install the control module. THE MOTOR IS DEFECTIVE AND MUST BE REPLACED. Installing the new control module will cause it to fail also.

7.Verify that the replacement control is correct for your application. Refer to the manufacturer's authorized replacement list.

USING THE WRONG CONTROL WILL RESULT IN IMPROPER OR NO BLOWER OPERATION. Orient the control module so that the 3-wire motor plug can be inserted into the socket in the control. Carefully insert the plug and press it into the socket until it latches. A SLIGHT CLICK WILL BE HEARD WHEN PROPERLY INSERTED. Finish installing the replacement control per one of the three following paragraphs, 8a, 8b or 8c.

8a. IF REPLACING AN ECM 2.0 CONTROL (control in cast aluminum can with air vents on the back of the can) WITH AN ECM

2.3CONTROL (control containing black potting for water protection in black deep-drawn steel case with no vents in the bottom of the can), locate the two through-bolts and plastic tab that are packed with the replacement control. Insert the plastic tab into the slot at the perimeter of the open end of the can so that the pin is located on the inside of the perimeter of the can. Rotate the can so that the tab inserts into the tab locater hole in the endshield of the motor. Using the two through- bolts provided with the replacement control, reattach the can to the motor.

THE TWO THROUGH-BOLTS PROVIDED WITH THE REPLACEMENT ECM 2.3 CONTROL ARE SHORTER THAN THE BOLTS ORIGINALLY REMOVED FROM THE ECM 2.0 CONTROL AND MUST BE USED IF SECURE ATTACHMENT OF THE CONTROL TO THE MOTOR IS TO BE ACHIEVED. DO NOT OVERTIGHTEN THE BOLTS.

8b. IF REPLACING AN ECM 2.3 CONTROL WITH AN ECM

2.3CONTROL, the plastic tab and shorter through-bolts are not needed. The control can be oriented in two positions 180° apart. MAKE SURE THE ORIENTATION YOU SELECT FOR REPLACING THE CONTROL ASSURES THE CONTROL'S CABLE CONNECTORS WILL BE LOCATED DOWNWARD IN THE APPLICATION SO THAT WATER CANNOT RUN DOWN THE CABLES AND INTO THE CONTROL. Simply orient the new control to the motor's endshield, insert bolts, and tighten. DO NOT OVERTIGHTEN THE BOLTS.

8c. IF REPLACING AN ECM 2.0 CONTROL WITH AN ECM 2.0 CONTROL (It is recommended that ECM 2.3 controls be used for all replacements), the new control must be attached to the motor using through bolts identical to those removed with the original control. DO NOT OVERTIGHTEN THE BOLTS.

9.Reinstall the blower/motor assembly into the HVAC equipment. Follow the manufacturer's suggested procedures.

10.Plug the 16-pin control plug into the motor. The plug is keyed. Make sure the connector is properly seated and latched.

11.Plug the 5-pin power connector into the motor. Even though the plug is keyed, OBSERVE THE PROPER ORIENTATION. DO NOT FORCE THE CONNECTOR. It plugs in very easily when properly oriented. REVERSING THIS PLUG WILL CAUSE IMMEDIATE FAILURE OF THE CONTROL MODULE.

12.Final installation check. Make sure the motor is installed as follows: a. Unit is as far INTO the blower housing as possible.

b.Belly bands are not on the control module or covering vent holes. c. Motor connectors should be oriented between the 4 o’clock and 8

o’clock positions when the blower is positioned in its final location and orientation.

d.Add a drip loop to the cables so that water cannot enter the motor by draining down the cables. Refer to Figure 25.

The installation is now complete. Reapply the AC power to the HVAC equipment and verify that the new motor control module is working properly. Follow the manufacturer's procedures for disposition of the old control module.

 

 

Figure 23

 

Figure 24

 

Control Disassembly

 

Winding Test

 

 

 

Motor Connector

Only remove

 

From Motor

(3-pin)

 

Hex Head Bolts

Push until

 

 

 

Latch Seats

 

 

 

Over Ramp

 

 

 

 

Circuit

 

 

 

 

Board

 

 

ECM 2.0

 

Motor

 

 

 

 

 

 

 

 

 

 

Motor OK when

Note:

 

 

 

R > 100k ohm

Use the shorter

 

 

 

 

bolts and

 

 

 

 

alignment pin

 

 

 

Figure 25

supplied when

 

 

 

replacing an

 

 

 

Drip Loop

ECM 2.0

 

Motor Connector

 

 

control.

 

 

Connector Orientation

 

(3-pin)

Back of

ECM

Control

Between 4 and 8 o'clock

 

2.3/2.5

Control Connector

 

 

 

 

(16-pin)

 

 

 

 

Power Connector

 

 

 

 

(5-pin)

 

 

 

 

Hex-head Screws

 

Drip Loop

Manual

2100-420H

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Contents Instructions Models QH243 QH302 QH362 QH422 QH482 QH602 Qtec Series Packaged Heat Pump InstallationContents For More INFORMATION, Contact These Publishers Getting Other Information and PublicationsFactory BUILT-IN Electric Heat Table Qtec Model NomenclatureElectrical Specifications on page 6 a Electrical SpecificationsModel Unit Dimensions Removal of Unit from Skid Shipping DamageUnit Removal from Skid AIR Seal Under Qtec UnitUnit on Appliance Cart Minimum Installation HeightHandling Unit After Removal from Skid GeneralInstallation with Free Blow Plenum Ducted Application Filter Location Duct WorkFilters Supply Duct ConnectionsStandard Rear Drain Optional Side Drain Side View InstallationFresh AIR Intake Condensate DrainRear Drain TOP View Service LightUnit Mounting Mounting the Unit Installation InstructionsRemoving Locking Screws from Wheels Operating Voltage Range Wiring Main PowerWiring LOW Voltage Wiring Component LocationLOW Voltage Connections for DDC Control LOW Voltage ConnectionsWall Thermostats Thermostat Predominant FeaturesRemote Thermostat Wiring Diagram Thermostat Option Unit Mounted Thermostat Wiring Diagram Thermostat Option Unit Mounted Thermostat Wiring Diagram Thermostat Option Start UP Mist Eliminator Service Service HintsBarometric Fresh AIR Damper Standard Vent OptionsFresh AIR Damper Removal Qerv Removal Heat Pump Control Board HPC Pressure Service PortsSequence of Operation Optional Climate Controls Sequence of OperationDefrost Cycle LOW Pressure Control Bypass TimerTroubleshooting TroubleshootingChecking Temperature Sensor Solid State Heat Pump Control Troubleshooting ProcedureTemperature F VS Resistance R of Temperature Sensor Don’t Troubleshooting GE ECM MotorsReplacing ECM Control Module Troubleshooting GE ECM Motors CONT’DIndoor Blower Performance FAN Blade Setting Dimensions Refrigerant ChargeFAN Blade Setting FAN Blade Dimensions Super Heat AT CompressorModel Temp Pressure Cooling Pressure ALL Temperatures in Degrees FReturn AIR Temperature Entering Outdoor Coil Model Pressure Heating Pressure ALL Temperatures in Degrees F

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