Dixell XR35CX and XR40CX

Two-relay panel controllers. The XR40CX runs compressor and defrost (electric or hot gas). The XR35CX runs the compressor with off-cycle defrost plus a configurable second relay, and can have a real time clock.

What it is: Refrigeration controller with defrost. Covers XR35CX and XR40CX. Both 32×74 mm with a room and an evaporator probe.

Key combo: Hold SET + DOWN for 3 s for the user level. Hold SET + DOWN again for over 7 s for the hidden menu (Pr2).

Error codes ↓
Enter service mode ↓
Parameters ↓
Change a setting ↓

Dixell XR35CX and XR40CX error codes

Code	Meaning	Likely cause	How to reset
P1	Room (thermostat) probe fault	Probe open, shorted, unplugged or wrong type (PbC)	Clears by itself a few seconds after the probe reads normally. Check wiring and PbC before replacing the probe. Compressor cycles on the COn / COF times meanwhile.
P2	Evaporator probe fault	Probe open, shorted, unplugged or wrong type (PbC)	Clears by itself a few seconds after the probe reads normally. Check wiring and PbC before replacing the probe. Defrost ends on time (MdF) meanwhile.
P3	Third probe fault	Probe open, shorted, unplugged or wrong type (PbC)	Clears by itself a few seconds after the probe reads normally. Check wiring and PbC before replacing the probe. Outputs carry on as normal.
P4	Fourth (condenser / Hot Key socket) probe fault	Probe open, shorted, unplugged or wrong type (PbC)	Clears by itself a few seconds after the probe reads normally. Check wiring and PbC before replacing the probe. Outputs carry on as normal.
HA	High temperature alarm	Room probe above ALU for longer than ALd	Clears by itself once back inside the limit. Outputs unchanged.
LA	Low temperature alarm	Room probe below ALL for longer than ALd	Clears by itself once back inside the limit. Outputs unchanged.
HA2	Condenser high temperature	Condenser probe above AU2 (dirty condenser, fan fault)	Clears when the temperature drops. Compressor stops only if AC2 = y.
LA2	Condenser low temperature	Condenser probe below AL2	Clears when the temperature rises. Compressor stops only if bLL = y.
dA	Door open alarm (i1F = dor)	Door switch open longer than did	Clears when the door closes. Compressor follows rrd.
EA	External alarm (i1F = EAL)	Digital input active longer than did	Clears when the input goes back to normal. Outputs unchanged.
CA	Serious external alarm (i1F = bAL)	Digital input active	All outputs off. Clears when the input goes back to normal.
CA	Pressure switch alarm (i1F = PAL)	Pressure switch tripped nPS times within did	All outputs off. Power the controller off and on to reset.
rtc	Clock has lost its time	Real time clock not set or lost after a long power cut	Set the time and date in the clock menu. Defrosts run on IdF meanwhile.
rtF	Clock board fault	Real time clock failed	Defrosts run on IdF meanwhile. Controller needs repair or replacement.

How to enter service / parameter mode

Hold SET and DOWN together for 3 seconds. The °C or °F light flashes: you are in the user level (Pr1).
Let go, then hold SET and DOWN again for more than 7 seconds. Pr2 shows, then Hy. You are now in the hidden menu with every parameter.
If the user level is empty, noP shows first. Keep holding until Pr2 appears.

Parameter list

Code	What it does	Range	Default / typical
Set	Set point (target temperature)	LS to US	XR40CX −5.0 °C; XR35CX 3.0 °C
Hy	Differential: compressor cuts back in at set point + Hy	0.1–25.5 °C	2.0 °C
LS	Lowest set point a user can choose	−50 °C to set point	−50.0 °C
US	Highest set point a user can choose	Set point to 110 °C	110 °C
Ot	Room probe offset (calibration)	−12 to 12 °C	0.0
P2P	Evaporator probe fitted? (n = no, defrost ends on time)	n / Y	Y
OE	Evaporator probe offset	−12 to 12 °C	0.0
AC	Minimum off time between compressor stop and restart	0–50 min	1 min
COn	Compressor run time per cycle when the room probe has failed	0–255 min	15 min
COF	Compressor stop time per cycle when the room probe has failed	0–255 min	30 min
tdF	Defrost type	EL (electric) / in (hot gas)	EL
dtE	Evaporator temperature that ends defrost	−50 to 50 °C	8 °C
IdF	Time between defrost starts	1–120 h	XR40CX 6 h; XR35CX 8 h
MdF	Longest a defrost can run (or fixed length with no evaporator probe)	0–255 min	XR40CX 30 min; XR35CX 20 min
dFd	What the display shows during defrost	rt, it, SEt, dEF	it
dAd	Longest the display stays frozen after defrost	0–255 min	30 min
ALU	High temperature alarm limit	Set point to 110 °C	110 °C
ALL	Low temperature alarm limit	−50 °C to set point	−50.0 °C
ALd	Delay before a temperature alarm shows	0–255 min	15 min
did	Delay before a digital input alarm shows	0–255 min	Check on unit
odc	What stops when the door opens	no, Fan, CPr, F_C	Check on unit
PbC	Probe type (PTC or NTC; Pt1000 on some versions)	PTC / NTC (XR35CX: Pt1000 / NTC)	NTC

How to change and save a setting

Scroll with UP or DOWN to the parameter code.
Press SET to show its value.
Change it with UP or DOWN.
Press SET to store it and move to the next parameter.
To leave, press SET + UP or wait about 15 seconds. Values are kept either way.

Other useful key presses

Task	How
Lock or unlock keys	Hold UP + DOWN for 3 s. PoF = locked, Pon = unlocked.
Lowest / highest recorded temperature	Tap DOWN (Lo) or UP (Hi). Hold SET while it shows to clear it.
Move a parameter between Pr2 and Pr1	In the hidden menu press SET + DOWN on the parameter. A lit decimal point means it is in Pr1.
Other messages	noP = nothing in Pr1 or that probe is disabled; noA = no alarm stored.

Notes

rtc and rtF only appear on XR35CX units fitted with the real time clock.
XR35CX has two digital inputs (i1F and i2F) and a Day/Night energy-saving set point.
XR40CX can use the digital input as a fourth probe.

For licensed technicians only. This equipment can involve mains voltage, high-voltage microwave circuits, gas and refrigerant. Isolate power (and gas) before opening panels, follow the manufacturer's manual and your local licensing rules (for example ARC refrigerant handling and electrical or gas licences). Wrong settings can spoil food or damage equipment. Check every value on the unit in front of you before changing it.

Based on: Dixell XR35CX and XR40CX installing and operating instructions. Always check the manual for your exact model and software version.

ServiceModes is not affiliated with Dixell or any other manufacturer. Written in our own words from the manufacturer's documentation.