Brand: Emerson
Category: HVAC Controls
Document Type: Manual
Language: EN
Manual for EXD-SH1/2
Uploaded: April 20, 2026, 7:47 p.m.
Manual Publish Date: 2020-07-29
Warranty Information
Refer to the warranty information provided with the product.
The EXD-SH1/2 is a standalone superheat and/or temperature controller. EXD-SH1 is intended for operation of one bipolar electrical control valve, whereas EXD-SH2 is designed for operation of two independent bipolar electrical control valves. It offers various control modes and functions for optimizing refrigeration systems. The unit can be configured via a keypad or ModBus communication.
Troubleshooting and error codes
| Symptom | Cause | Action | Requires alarm clear after resolving alarm? |
|---|---|---|---|
| Operating superheat is several degrees higher or lower than set-point | Incorrect signal from pressure or temperature sensors | 1- Check the sensors (see list of parameters) 2- Make sure the sensor cables are not installed along with other high voltage cables |
No |
| Operating superheat is too low i.e. compressor wet running | 1- Incorrect wiring of ECVs 2- Defective sensors |
1- Check the wiring 2- Check the sensor |
No |
| Valve is not fully closed | 1- The digital input is ON 2- Wrong setting of parameter ut. |
1- Valve is shut off only when the digital input is turned off. 2- Check the setting of parameter ut. |
No |
| Instable superheat (hunting) | Evaporator is designed to operate at higher superheat | Increase the superheat set-point. | No |
| Valve opens when EXD commands to close and vice versa | Wrong wiring between EXD-SH... and valve | Correct the wiring. | No |
| EX8 is not able to open at high differential pressure | Wrong setting of parameter ut | Check the parameter ut. (Larger valve requires higher torque and higher current) | No |
| Superheat set-point is shifting after several months of uninterrupted operation or permanent jumper of 24 V digital input | Stepper motor driven valves require synchronization | Do not jumper digital input permanently. Interrupt digital input once every week for 10 seconds if compressor never stops. | No |