Kolpak Walk-In Cooler Error Code DEFR TERM ON TIME: Defrost Ended on Time
DEFR TERM ON TIME means the last two defrost cycles ended because the time limit ran out, not because the coil reached its termination temperature. Press ENTER on the display to silence the alarm for one hour. The room usually keeps cooling, but a technician should find out why the coil is not reaching temperature.
Medium: the room keeps cooling, but defrost is not finishing normally and ice can build over time.
- Code
- DEFR TERM ON TIME
- Maker
- Kolpak
- Equipment
- Walk-in coolers & freezers
- Applies to
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
What does Kolpak DEFR TERM ON TIME mean?
A walk-in defrost cycle is meant to end on temperature: the controller watches the coil and stops heating when it is warm enough that the ice is gone. A time limit sits behind that as a backstop. When the backstop ends the cycle instead of the temperature reading, the controller treats it as a sign that something is off. The ArcticFox controller keeps count, and when defrost ends on time instead of on temperature for two consecutive cycles it posts the text alarm DEFR TERM ON TIME in the Alarms menu. A single timed ending is not reported; two in a row are. The alarm does not stop refrigeration or the defrost schedule. It is a notice that defrost is no longer finishing the way it was set up to.
Affected models and control systems
ArcticFox OEM Controller with Deluxe Display, as fitted to Kolpak walk-in coolers and freezers. The manual lists this alarm in the Alarms menu (page 16) and states no model or board limit.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- DEFR TERM ON TIME shown in the Alarms menu
- Audible alarm from the display until ENTER is pressed
- Frost or ice building on the evaporator coil between cycles
- Alarm sounding again an hour after being silenced
Possible causes
Likely causes — what usually sits behind DEFR TERM ON TIME on this control. A technician confirms which one it is before any part is replaced.
- Evaporator defrost heater too weak or open, so the coil never reaches the termination temperature before the timer ends the cycle
- Defrost termination sensor reading wrong because it is loose on the coil or has slipped from its clip
- Heavy ice load from a door left open or a warm product load, which needs longer than the set defrost time
- Termination temperature or time limit changed from the values the room was commissioned with
Safe checks before calling for service
- Press ENTER on the display to silence the alarm. It stays quiet for 1 hour and sounds again if the condition has not been corrected.
- Look at the room door and gasket. Confirm the door closes fully and nothing is propped in the opening.
- From the floor, look at the evaporator coil if it is visible. Do not open any panel. Note whether it is heavily iced.
- Note the exact alarm text, when it began, and any room temperature change for the technician.
How a technician diagnoses DEFR TERM ON TIME
- Read the Alarms menu and defrost settings, and record the defrost termination temperature and the time limit as programmed.
- Watch a full defrost cycle and note the coil temperature at the point the cycle ends.
- Check the defrost heaters or hot gas circuit, whichever the room uses.
- Test the termination sensor with a meter against its temperature-resistance chart and confirm it is clipped to the coil where it belongs.
- Correct the heater, sensor, or setting causing the timed ending, then run a manual defrost and confirm it ends on temperature.
- Defrost heaters on a walk-in run on high-voltage circuits that must be tested with the panel open and the power on.
- On hot gas systems, diagnosing the defrost needs gauges on the refrigerant circuit, which is work for a licensed technician.
- Changing defrost settings without the room's design values can leave the coil iced.
Technical reference
- Document
- ArcticFox Deluxe Display - Original Instructions, Installation, Operation and Maintenance Manual
- Edition
- Part No. 500002385-4, 5/23
- Models / control
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
- Section
- ArcticFox OEM Controller - Alarms Menu, p.16
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Kolpak walk-in cooler & freezer error codes
Can I keep using the walk-in with this alarm?
Usually yes, since the alarm is a notice and refrigeration continues. Watch the room temperature and have the defrost checked soon.
Will DEFR TERM ON TIME clear on its own?
The manual only describes silencing it for one hour. The condition has to be corrected, so expect it to return until then.
Does this mean the coil is frozen solid?
Not necessarily. It means two defrosts ended on the timer. A technician needs to look at the coil.
Need help with Kolpak DEFR TERM ON TIME?
A technician confirms the cause on site and gives you the price in writing before any work starts.