KE2 Low Temp+Defrost Controller: Condensed Quick Start Guide
Product Number: 20903
Publication Date: June 2019
Parts List
[Illustration of controller, sensors, wiring, and various connectors and screws]
| Item | Description | Quantity |
|---|---|---|
| A | KE2 Low Temp controller | 1 |
| B | High voltage safety shield | 1 |
| C | Temperature sensors | 2 |
| D | 90° spade connectors | 6 |
| E | Straight spade connectors | 2 |
| F | Self-tapping screws | 5 |
| G | 1/2" plastic knockout plug | 1 |
| H | Air sensor mount | 1 |
| I | Coarse thread screws | 3 |
| J | Controller programming sticker | 1 |
| Warranty card (not shown) | 1 |
Complete Instructions
For complete instructions, visit: https://ke2therm.com/product/ke2-low-temp-defrost/ and click the 'Link to Literature' button.
Alternatively, use the QR code for KE2 Low Temp Literature or visit the KE2 Low Temp YouTube channel for videos.
Indicator Lights
- Red light: Basic Menu - not used; Advanced Menu - heater pulsing enabled.
- Yellow light: Non-critical alarm (system running).
- Green light: Compressor on.
- Green flashing: Compressor waiting on timer to start/stop.
Navigation
- Access Setpoints by pressing & holding [ENTER] until 'tS' (temp setpoint) is displayed.
- Use the [arrow up] & [arrow down] buttons to scroll through available setpoints.
- Press [ENTER] to view the current setting.
- Use [arrow left] & [arrow right] to change the setpoint.
- Press [ENTER] to move between digits to accelerate changes.
- Press and hold [ENTER] to confirm each setpoint change.
- Press [BACK] to escape.
Accessing the Menus
Basic Menu: Press and hold [ENTER] for 3 seconds.
Advanced Menu: Press and hold [BACK] then [ENTER] for 3 seconds.
The menus display setpoints and variables. Some are non-adjustable (view only).
Basic Menu / Default Menu (Non-Adjustable):
- tS (Temperature Setpoint)
- diF (Differential)
- CSH (Max. Compressor Starts/Hour)
- dtyP (Type of Defrost: Air or Electric)
- dPd (Defrost Per Day) - Only visible if CUS (custom) selected for dPd.
- tOd (Time of day)
- d1 to d12 (Start time of Defrost #1 to #12) - Only visible if CUS (custom) selected for dPd.
- diS (Defrost termination time)
Variables Menu (Non-Adjustable, view only):
- rtP (Room temperature)
- Clt (Coil temperature)
- SySt (System state)
- CPrl (Compressor relay)
- dFrl (Defrost relay)
- Fnrl (Fan relay)
- ALSt (Alarm state)
Additional variables are visible based on auxiliary input configuration (AU1, AU2).
For a complete list of setpoints and descriptions, see document Q.3.29.
Wiring Diagram
[Illustration of the wiring diagram showing connections for power supply (115/230 VAC), KE2 Terminal Board, fans, compressor relay, defrost relay, solenoid, and heaters, including wire colors and terminal labels like L1, L2, COM, NC, NO, FAN/S, etc.]
This diagram details the connections for the KE2 Low Temp controller, including power supply, evaporator fans, compressor relay, defrost relay, liquid line solenoid, and defrost heaters.
Basic Setpoints
| Setpoint | Description | Min. | Default | Max. |
|---|---|---|---|---|
| tS | Temperature Setpoint | -50°F | -10°F | 100°F |
| diF | Differential | 1° | 5° | 30° |
| CSH | Max. Compressor Starts/Hour | 5 (Off)* | 6 | 10 |
| dtyP | Type of Defrost, Air or Electric | Air | Elec | Elec |
| dPd | Defrost Per Day | 0 | 4 | 12, CUS |
| tOd | Time of day | 0:00 | 12:00 | 23:59 |
| d1 to d12 | Start time of Defrost #1 to #12; Only visible if CUS (custom) is selected for dPd | 0:00 | 23:59 | |
| diS | Defrost termination time | 0:00 | 23:59 | |
| dtsP | Defrost Term Temperature | 35 | 50 if Elec; diSA if Air | 90 |
| dFt | Defrost Time | 0 min | 30 min | 720 min |
| drnt | Drain Time | 0 min | 2 min | 15 min |
| FndF | Fan State During Defrost | OFF if Elec; On if Air | OFF | On |
| HAO | High Alarm Offset | 0° | 10° | 50° |
| LAO | Low Alarm Offset | 0° | 4° | 10° |
| tAd | Temp Alarm Delay | 1 min | 90 min | 180 min |
IMPORTANT: Determine the Coil Sensor Location
When arriving on site, put the system into defrost and observe where the frost on the coil disappears last. Place the sensor where you observed the frost disappearing last. Monitor the coil's air entering and air exiting side. Often, the last place frost disappears is on the air exiting side, near the right or left end. It is important to verify all heating elements are working properly.
[Illustration showing typical sensor placement on evaporator coil fins, approximately 1 to 1-1/2 inches from the edges, near the bottom third of the coil. Ice tends to grow from the edges inward. Avoid installing the coil sensor on U-bends.]
The sensor needs to be as far away from the defrost heat sources as possible.
Note: To prevent sensor wire damage from sharp edges, insert plug G (from Parts List) into the coil housing. Puncture the plug to insert the sensor wire.
The sensor should touch two circuit tubes. When inserting the sensor into the coil, the tip should touch one of the circuit tubes. Position it half way between heating elements if possible, not next to them. In some cases, the probe is inserted into the fins approximately 1/16" deeper than the stainless shielding. Pinch the fins gently together, securing the sensor. This provides thermal ballast, ensuring a complete defrost.
Alternate Method: As the defrost termination sensor, it is important that the sensor does not terminate defrost before all frost is removed from the coil. In some installations, inserting the sensor into the coil may position it too close to the defrost heat source. An alternate method of positioning places the sensor vertically between the coil fins. Pinch fins together gently, securing the sensor.
[Illustration showing the last spots to defrost, typically at the edges of the coil.]
[Illustration showing typical sensor location: approximately 1-1/2 inches from the end, in the bottom third of the coil.]
[Illustration showing Item G (plastic knockout plug) from the Parts List.]
Extending Sensor Wires
After sensors are mounted, route wires back to the controller. If wires must be extended, use 18-gauge twisted shielded pair. Maximum recommended length for 18-gauge wire is 100 feet.
When running wires back to the controller, be careful not to introduce noise into the sensor wires. This occurs when sensor wires are located near high voltage lines (defined by UL as greater than 30V). Do not run sensor wiring in the same conduit as high voltage lines. If crossing a high voltage line is necessary, run the sensor wiring at right angles to minimize noise.
