If a Greenheck Vari-Green motor won't run, check the speed signal before you condemn the motor. Greenheck's Vari-Green manual (473681) says a 0-10 VDC motor is off from 0 to 1.9 V and runs from 2 to 10 V, and a 0-5 VDC motor in the 318003 to 328179 range is off from 0 to 0.9 V and runs from 1 to 5 V. If the signal is in range, confirm that power and 24 V are present at the motor, that every connection is secure, and that the fan wheel turns freely.
Start with the speed signal
A Vari-Green motor treats a low control voltage as an off command. The motor is not faulted at that point; it is doing what the signal tells it to. Measure the signal at the motor, not at the controller, and compare it with the table below.
| Signal type | Motor off | Motor runs | Source |
|---|---|---|---|
| 0-10 VDC input | 0 to 1.9 V | 2 to 10 V | Greenheck 473681 |
| 0-5 VDC input (318003 to 328179 motors) | 0 to 0.9 V | 1 to 5 V | Greenheck 473681 |
| 0-5 V dial-on-fan control (386512) on motor 328447 | 0 to 1 V | 2 to 5 V | Greenheck 473681, 0-5V dial on fan entry |
The manual gives two different off thresholds for 0-5 V setups. Use the entry that matches your motor's part number and control.
If the motor has a dial, look at it first. Turning the dial counterclockwise lowers the speed signal, and a low enough signal reads as off. For the 310420 and 311156 motors, the manual says plainly that turning the dial fully counterclockwise turns the motor off. A dial left at its stop looks exactly like a dead motor.
Wire colors differ by motor family. On the 9-pin harness for the 310359 to 317887 motors, the manual lists red as +0-10 VDC, white as common and black as +24 VAC/DC, with the common shared by the 24 V supply and the 0-10 V signal. The table for the 318003 to 328179 families also lists red for +0-10 VDC and white for common, and lists black as a 5 VDC supply. Check the table for your motor's part number before you put a meter on it.
The manual's checks when the motor does not operate
For the 310359 to 317887 motors, the troubleshooting list headed "Motor does not operate" gives four checks:
- Connections. Check all wiring connections to make sure they are correct and secure.
- Voltages. Verify that all voltages are present at the motor, including 24 V and 0-10 VDC where your motor uses them.
- Fan wheel. Make sure the fan wheel rotates freely and that nothing is caught in it.
- Control wiring. If the motor has both a dial on the motor and the 0-10 VDC control option, disconnect the control wires from the motor. The motor should then run using the dial on the motor for speed control.
Split the problem: motor or building signal?
The manual's fourth check is the fastest way to split the problem. The manual also says a potentiometer (part number 385806) can be plugged into the motor's 9-pin connector, which gives the motor a local speed input that does not depend on the building controls. If the motor runs on the dial but not on the building's 0-10 V signal, the problem is upstream of the motor: the controller, the signal wiring or the common. If it still will not run with good power, a good local signal and a free wheel, the motor itself becomes the suspect.
Check the supply voltage jumper
On motors with a red jumper wire on the side of the motor, that jumper sets the supply voltage. The manual says the red jumper must be connected (closed) for 115 V and disconnected (open) for 208 V to 277 V operation. Confirm the jumper matches the supply before you go further.
Motors with a separate control box (310420 and 311156)
On the 310420 and 311156 motors, the manual says all high- and low-voltage connections are made inside a motor control box at the factory. That part of the manual adds its own checks:
- Wait before you open it. Disconnect power and wait at least five minutes for the capacitors to discharge before entering the control box.
- Allow for the start delay. For the 310420 and 311156 motors, the manual says there can be up to a 30 second delay between applying power and the motor starting.
- Check the voltage. The 2 HP motor, 310420, is 208-240 V only.
- Check the jumper between terminals 9 and 10. The manual says to verify it is in place; the motor will not run without it.
- Check the yellow motor wires. Verify the two yellow wires from the motor are on terminals 5 and 6.
- Force full speed to test. A jumper between terminals 1 and 2 forces the motor to run at full speed. This tells you whether the motor runs at all without the control signal.
- Read the red LED. These motors have a diagnostic red LED on the circuit board inside the control box. It is solid when power is applied and the motor is operating normally. The manual notes the LED may be solid even when the motor is not spinning, for example when it is commanded off with a 0 to 1.9 V signal. A fault makes it blink 2 to 9 times, pause and repeat.
| Red LED blinks | Fault (Greenheck 473681) |
|---|---|
| Solid, not flashing | Power applied, motor operating normally |
| 2 | Hardware fault |
| 3 | Overvoltage |
| 4 | Undervoltage |
| 5 | Communication error |
| 6 | Sync loss |
| 7 | Spin fault |
| 8 | Motor overload |
| 9 | Motor over temperature |
Count the blinks two or three times to confirm, as the manual recommends. Under most faults these motors restart automatically. The exception is overload: if a motor overload fault occurs more than 10 times in one hour, the motor shuts down and needs a power cycle to reset.
Parts involved
| Component | Role in this issue | Where to find it |
|---|---|---|
| Plug-in dial | The manual's 385806 potentiometer plugs into the motor's 9-pin connector. Useful as a local speed input and a test tool. | 385806 — Plug-in Dial for Vari-Green Motor |
| Remote dial | The manual says 385803 remote dials can set minimum and maximum voltage limits. A minimum set too low can leave the motor off. | 385803 — Vari-Green Remote Dial, with Min/Max Setting |
| Dial-on-fan control | The manual lists 385611 as a control that mounts on the outside of a fan where the motor dial is hard to reach, such as model SQ. It is powered by line voltage and sends 24 VDC and 0-10 VDC to the motor. | 385611 — Vari-Green Dial On Fan Control |
| 0-5 V control | The manual lists 386512 as the 0-5 V dial-on-fan control, powered from the motor's 5 VDC supply wire. | 386512 — Control, Vari-Green, Cntrl,Potmtr,Vari Grn,Dial 0-5V |
| Control transformer | The manual references a factory-mounted transformer, 385253. | 385253 — Vari-Green Control Transformer, 85V-277V |
| 0-10 V signal harness | A damaged or loose harness is one way the signal never reaches the motor. Harnesses are listed by pin count, wire count and length. | 384804 — Vari-Green 0-10V Harness, 9 Pin, 3-Wire, 18 Inch |
| Vari-Green motor | Replace only after the signal, power, wiring and wheel checks pass. Match the Greenheck part number on your motor. | Valent, Innovent and Greenheck replacement parts |
Scope: This article covers Greenheck Vari-Green motors and controls as described in the Vari-Green Motor and Controls IOM, document 473681 (Rev. 14, August 2019). Signal thresholds, wire colors and terminal checks differ between motor families in that manual. Use the section for your motor's part number, and treat the products above as examples, not a fit confirmation for your fan.
Before you order
Read the Greenheck part number from the motor label and the fan model and serial number from the fan nameplate. If the nameplate is missing, see how to find Greenheck parts by serial number or without a nameplate. For general motor-versus-electronics testing, see how to test an ECM motor. To confirm fit, contact us at help@totalhvacparts.com with the fan model, serial number and motor part number.
Frequently Asked Questions
What voltage turns a Greenheck Vari-Green motor on?
On a 0-10 VDC input, Greenheck's manual 473681 says the motor is off from 0 to 1.9 V and runs from 2 to 10 V. On a 0-5 VDC input (318003 to 328179 motors) it is off from 0 to 0.9 V and runs from 1 to 5 V; with the 0-5 V dial-on-fan control on motor 328447, it is off from 0 to 1 V and runs from 2 to 5 V.
Why does my Vari-Green motor not run with the dial turned down?
Turning the dial counterclockwise lowers the speed signal, and below the on threshold the motor stays off. For the 310420 and 311156 motors, the manual says fully counterclockwise turns the motor off. Turn the dial up and recheck the signal at the motor.
Does a Vari-Green motor need a jumper to run?
On the 310420 and 311156 motors with a separate control box, the manual says to verify a jumper between terminals 9 and 10; the motor will not run without it. Separately, motors with a red voltage jumper need it closed for 115 V and open for 208 V to 277 V.
What does a blinking red LED on a Vari-Green motor mean?
On the 310420 and 311156 motors with a control box, the red LED blinks 2 to 9 times for a fault: 2 hardware, 3 overvoltage, 4 undervoltage, 5 communication error, 6 sync loss, 7 spin fault, 8 overload and 9 over temperature. A solid LED means normal operation.
Sources
- Greenheck Vari-Green Motor and Controls Installation, Operation and Maintenance Manual, document 473681 (signal ranges, troubleshooting, voltage jumper, control box checks, LED codes)
- Live product titles for the parts listed above, as shown on each product page
Fan motors and controls involve line voltage, stored capacitor charge and rotating equipment. Service should be performed only by qualified personnel, following the manufacturer's manual for your unit and your facility's lockout/tagout procedures.