The purpose of this article is for Diagnosing EEV issue's and to share the location of the EEV circuit.
1.How to verify SW1 DIP switch settings are correct
It is recommended that prior to starting EEV diagnostics that the SW1 Dip switches are verified that they are set correctly.
- Here are the settings for all three series of Medium Foundation installed today. The first edition was the Legacy, then next was the DOE edition followed by the current A2L edition. Always look on the schematic located on the control cabinet cover for the correct configuration of the SW1 dip switches. The black squares on the drawing represent where the switch is located for each tonnage for the equipment being serviced.
- The SW1 dip switches are located on the Main board.
2. Locating the EEV for Cir.# 1 and Cir.#2
3. Next locate the plug on the board with the EEV diagnostic present.
Locate and remove the plug from the main board that has the error present.
4. How to OHM the EEV power head.
Coil resistance measurement
•Each EEV has 5 wires, the Gray wire is the common terminal
•Resistance between common terminal and other terminals: 46±4 Ω @ 68*
5. Measuring EEV coil voltage
The EEV will have 12 vdc +/-10% to open and close the valve during operation. This voltage is pulsing 30-90 PPS on one or two coils at a time depending on positioning of the valve.
There are four coils on the valve. Orange - Red- Yellow- Black. Each can be measured to the gray common wire.
Because this voltage is pulsing it may be difficult to measure with a meter. Make sure correct equipment is used for testing.
6. What controls the EEV positioning
The EEV is controlled during cooling operation based off the Discharge SH. It is measured between the T5 (Discharge Temperature) sensor and T3 (Condenser Temperature) sensor. These sensors should be verified for correct calibration.
Circuit A - T3A & T5A
Circuit B - T3B & T5B
The EEV uses a PWM signal to adjust the valve positioning. A + pulse to increase open and - pulse to decrease / close the valve. The valve position will not change if the SH is 36*-63*.
7. How to remove the EEV power head
Remove the rubber weather boot from the top of the EEV so expose the valve assembly and set it aside for now.
8. Removing the Power Head from the valve body
- The Power Head is locked onto valve locking ring on the bottom side.
2. Notice the Power head lock slides under the valve locking ring.
3. To remove the Power Head just turn it 180 degrees to the unlocking position and left off the Power Head off the valve body.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.