40 TO-Series Oil Cooler (Clone)

40.1 Application Range

This cooler unit is designed for cooling of hydraulic heat source, spindle lubrication/cooling system of machine tools(picture 1). It can provide precise control of the oil temperature. Please refer to picture 2 for application.

40.2 Oil Use

This cooler unit accepts mineral hydraulic oil and lubrication oil.

Please do not use any of the following oil:

Phosphate, chlorinated hydrocarbon, and fire resistant hydraulic oil such as water/glycol oil and W/O, O/W emulsion type hydraulic oil.
Cutting oil, grinding oil, water soluble liquid.
Food stuff, medicine and strongly corrosive liquid.
Gasoline, kerosene and organic solvent.

The recommended oil viscosity for this cooling unit is 10-300cSt. When the oil viscosity is too high or the length of the oil pipe connected to the machine tools is too long, it will cause loss of oil pressure and irregularly noise. To solve this problem, please shorten the length of oil pipes outside the cooler unit, increase the diameter of the pipes and change to oil with lower viscosity.

40.3 Installation

Keep the cooler unit at upright position and avoid collision or shock during transportation. Do not incline, lay down or upside down the cooler unit.

Please locate the cooler unit in flat and shockproof places.

And it should be sheltered from direct sunlight. Area with heat source is also not recommended.

Please locate the cooler unit in dry, well-ventilated and dust-free places. Environment with ambient temperature is 10~40℃.

Do not let the machine take in the hot air it emits in case it goes wrong due to bad heat dissipation.

Please locate the cooler unit where it can be easily maintained and cleaned. Avoid the environment with

bad ventilation. Do not block the air outlet and inlet.(picture 3)

40.4 Wiring

Please connect the wire according to the electrical circuit diagram.

(picture 3)

Please make sure the grounding wire has been correctly connected. If the wiring needs changing, please disconnect the power source first.

Please open the case of wire, and don’t forget to close it after using it. 4-4 Please do not

handle the magnetic switch with hands.

4-5 It is necessary to install an electrical circuit breaker for the power source to avoid possible electrical shock or personal injuries.

40.5 Check the following before turning on the cooler unit.

Please check the power voltage, phase sequence, grounding wire and alarm connection. 5-2 Please check the oil pipe connection and any leakage in the oil circulating system.

Please check the wire connection (including the grounding wire).

Please check if there is sufficient oil in the tank or in the system. Note that insufficient oil within the system will cause damage to the oil pump.

Please check if the cooler has been properly located, good working environment with good ventilation and ambient temperature is within the operating range.

Note that frequent restart will damage the cooler unit. Please do not restart the cooler unit within 3 minutes after it’s been turned off.

The cooler unit should be turned on with working machine at the same time to control the oil temperature automatically. Do not start the cooler unit when the oil temperature is high. The cooler

unit will stop working if the temperature is high, which is one of the troubles.

There are chances of oil penetrated into the oil circulating system, which will cause decrease in flow rate and noise within the system. To remove air in the oil circulating system, please follow the following steps：

Input main power to the cooler unit, and pump will then start operating.
Slightly loose the oil pipe at oil outlet of the cooler unit to push the air out of the system and then tighten the pipe again.
Switch off the power input after air is out.

40.6 Operating Control

The control panel is electrically displayed.

External appearance of the control panel (picture 4)

① Power on/off ：

After input the power, press POWER key for 3 seconds, it will start operation or stop operation. This step can also be done through the remote control.

The cooler and the working machine work at the same time, so the stop or the operation of the cooler should be controlled by the working machine. When the cooler is functioning properly, please do not press POWER key to turn off the cooler.

② Operation Message：

PUMP： Light is on when the pump is operating.

COMP： Light is on when the compressor is operating; time delay is on.

POWER; Light is on when power is input.

③ Temperature display：

PV℃：Display the present liquid temperature.

SV℃：Display the set value or room temperature. (picture 4).

④ Temperature setting key：

Press PARA for 3 seconds to enter temperature setting state. SV℃ displays the set value. Then press UP or DOWN key to change the temperature. After setting, press PARA to exit and save the set value.

⑤ Shift between the set value and the room temperature.

Keep on pressing DOWN key to get the room temperature shown by SV℃； When stopping pressing it, SV℃ displays the set value. (This shift key is invalid if the temperature is fixed.)

⑥ Alarm message：

The cooler unit will stop functioning when it is working improperly and alarm message will display on the controlling panel. (Please refer to picture 9-2）

Operation explanation

After input the power, SV℃ and PV℃ will display “- - -”. With remote control connected, please long press POWER, the cooler unit and the pump will operate with PUMP light on. The cooler unit will operate according to the set value. (SV℃).

① Temperature setting range

Fix temperature control type：10℃ ~ 40℃。 Tracking temperature control type ：-10℃ ~ +10^。

② Temperature control means：Liquid temperature is controlled by SV℃. When PV℃ exceeds SV℃, the compressor will work. COMP light will be on. When PV℃ is below SV℃, the compressor will stop working. COMP light will be off. Tracking temperature control type： Control liquid temperature.

40.7 Maintenance

Before any maintenance, please follow the safety precautions. The cooler unit needs maintaining regularly to make it perform at its best cooling capacity and to prolong its lifetime. Please keep the cooler unit in a well-ventilated and obstruction-free environment.

Cleaning

Please switch off the main power source before proceeding any maintenance or cleaning. Removing any components during operation may cause serious injuries to personnel or even damage to the cooler.

List of components that require cleaning regularly：

cooler body
condenser
air filter
oil tank
oil filter

Please check below for detailed cleaning procedures：

Cooler body

Please clean the surface of cooling unit with neutral detergent or qualified soap. Do not clean the cooler with acid agents, grinding powder, steel brush and hot water to prevent the damage of the painted surface.

Don’t splash water to the components while cleaning.

Please wipe the components with dry cloth.
Condenser
Make sure the condenser is not blocked. Please clean the condenser with compressed air or hair brush regularly.
Air filter
Dismount the filter by pushing it up and then drawing it down as shown in picture 5.
Oil tank

If the cooler is located in humid places, eventually there will be water formed within the tank and sink at the bottom. Please drain the water from the tank once a month.
Oil filter
Please clean the oil filter once a day in the early stage after piping and every 2 or 4 times a day after normal operation.
1. Please store the cooler at dust free area.
2. Wipe the power cable clean before storing.
3. Please use cover to prevent dust and moisture.
4. Please store the cooler unit at flat ground with dry and cool environment.
5. If the cooler unit is assembled with carter wheels, please lock up the wheels to hold the cooler unit at position. Unlocked wheels may cause the cooler to move, which may cause serious injuries to personnel and damage to the cooler.

48.8 Maintenance security

If any repair or replacement of the parts are necessary, please pay attention to the following notes：

8-1 Please disconnect the power source when replacing the parts.

8-2 In the process of maintenance, if weld is needed, please be careful with fire produced in welding, which may cause fire accident. It is strongly recommended that oil in the oil tank should be drained and clean up the oil stain.

8-3 Please emit refrigerant in well-ventilated areas to avoid poisoning and suffocating.

48.9 Trouble shooting

Any maintenance and repair should be done by qualified technicians and follow the safety instructions. The cooler will stop working and alarm message is displayed if it goes wrong. The answers corresponding to the questions mentioned below are for your reference only. Please restart the cooler after the trouble is solved.

Leakage

If there is leakage in the oil pipe, please tighten the pipe or replace it. When welding tool is needed：

Please emit refrigerant in well-ventilated areas to avoid poisoning and suffocating.
Please be careful with fire accidents when draining all oil out of the cooler and disconnecting all oil pipes between machine tools and the cooler.
Please release refrigerant out of the cooler according to the relevant regulations of environment protection.

Trouble shooting of electronically shown type:

(1) Sudden stop during operation with alarm messages shown:

?	?	?
(A)	Explanation	The pump fault
A11	Possible Cause	Incorrect power voltage input. Poor insulating or a burn out pump. Trip-out in overload protector. Obstruction in the liquid pipe.
Inspection	Check if the power voltage input is proper. Check if the pump motor still operates. Check if the bearing is cloggy. Check if the overload protector has triggered. Check if the liquid flow is smooth in the liquid pipe.
Solution	Input correct power voltage. Replace faulty pump. Reset the overload protector. Clean the liquid circulating system, add a filter if necessary.
(B)	Explanation	The compressor fault
A12	Possible Cause	Incorrect power voltage input Compressor has burned out Overload protector trip out Poor heat dissipation Fan failure
Inspection	Check if the input power voltage is correct. Check the compressor. Check if the overload protector has tripped out. Check if the internal temperature of the cooler is too high. Check if the fan motor works properly.
Solution	Input the correct power voltage. Replace the burned out compressor. Reset the overload protector. Improve the working environment to create better ventilation. Replace the fan.
(C)	Explanation	There is an oil pressure fault or insufficient oil amount within the system.
A13	Possible Cause	No liquid flow or insufficient oil. Oil pressure loss. Oil pressure switch failure. Flow rate switch failure. Air penetrated into oil circulating system Pump motor failure. Oil viscosity is too high.
Inspection	Check if there is enough oil within the oil circulating system. Long, thin and flattened oil hoses will cause oil pressure loss. Please check if the value of oil pressure switch is within the designed specification. If the pump motor fails, there will be no oil flow. Check if there’s any air penetrated into the oil circulating system. Check if oil viscosity is within the suitable range. If all the above checked is all right, there is a chance of failure in oil pressure switch or the flow rate switch.
Solution	Supply more oil into the oil tank or the oil circulation system to the rated level. Increase the diameter of the hose or shorten the length of hose to avoid oil pressure loss. Reset the oil pressure switch to designed specification. Replace faulty pump motor. Please remove the air within the system. Please refer to 5-8 before operation. Use oil with lower viscosity. Replace faulty parts.
(D)	Explanation	There is a pressure fault within the refrigeration system.
A14	Possible Cause	Low or over charge of refrigerant. Obstruction or leakage in the refrigerant system. Condenser or air filter is dirty or cloggy. Poor heat dissipation. Fan failure.
Inspection	Check if the copper pipe near the low pressure side of the compressor is not cold. Check if the fins of the condenser are not hot and the temperature of the dryer is too low. Check if the air filter or the condenser is dirty or cloggy. Check if the internal temperature of the cooler is too high. Check if the fan works properly.
Solution	Please contact the refrigeration service technician for faults within the refrigeration system. Clean the air filter and condenser regularly to improve the air dissipation, and remove any obstructers from air intake or exhaust.
(E)	Explanation	The power phase input has been reversed.
A17 A41 A42	Possible Cause	Reversed phase of main power source. Power source is single-phased. Reverse-phase relay failure or temperature controller failure.
Inspection	Check if the power voltage input is correct. Check if the power phase input is correct. If the power phase input is correct, there is a chance of the reverse-phase relay or the temperature controller failure.
Solution	Reconnect the power cable with correct phase. Three phase cooling unit should be connected to three phase power source. Replace the faulty parts.
(F)	Explanation	Surface temperature of the compressor is too high.
A18	Possible Cause	Poor heat dissipation. The cooler is not cleaned regularly. Incorrect power voltage input. Faulty compressor.
Inspection	Check if any air vent is cloggy. Check if the power voltage and phase input is correct. Check the starting condition of the compressor and the operating power.
Solution	Create better heat dissipation environment and maintain the cooler regularly. Input correct power voltage and phase. Replace faulty compressor.
(G)	Explanation	Liquid temperature sensor fault.
A21/ OPE	Possible Cause	Broken connection of the liquid temperature sensor. Temperature control failure.
Inspection	Check if the connection of the liquid temperature sensor is broken. If the connection is not broken, then there are chances of temperature controller failure or sensor failure.
Solution	Reconnect the wire. Replace the wire.
(H)	Explanation	The basic temperature sensor fault.
A22/ OPE	Possible Cause	The wire connection of the basic temperature sensor is broken. The temperature controller failure.
Inspection	Check if the wire for basic temperature sensor still connected. If the connection is not broken, then there are chances of temperature controller failure or sensor failure.
Solution	Reconnect the wire. Replace the faulty parts.
(I)	Explanation	Liquid temperature is too high.
A31	Possible Cause	Liquid temperature exceeds 50°C. The cooling capacity of the cooler is low. Liquid temperature sensor failure. Refrigeration system failure, either blocked or leaked.
Inspection	Check if the liquid temperature and ambient temperature exceed 50°C. Check if the cooler works with the machine tools at the same time. Check if the cooler unit is capable for the process load. The cooper pipe near the low pressure side of the compressor is not cold. The fins of condenser are not hot. The temperature of the dryer is too low. Check if the sensor functions properly.
Solution	Keep the liquid temperature below 50°C. Please note that the cooler unit and the machine tools should start at the same time. Replace the cooler unit with a larger cooling capacity. Replace the liquid temperature sensor. Please contact the refrigeration service technician for faults within the refrigeration system.

(A)

Explanation

The pump fault

A11

Possible Cause

Incorrect power voltage input.

Poor insulating or a burn out pump.

Trip-out in overload protector.

Obstruction in the liquid pipe.

Inspection

Check if the power voltage input is proper.

Check if the pump motor still operates.

Check if the bearing is cloggy.

Check if the overload protector has triggered.

Check if the liquid flow is smooth in the liquid pipe.

Solution

Input correct power voltage.

Replace faulty pump.

Reset the overload protector.

Clean the liquid circulating system, add a filter if necessary.

(B)

Explanation

The compressor fault

A12

Possible Cause

Incorrect power voltage input

Compressor has burned out

Overload protector trip out

Poor heat dissipation

Fan failure

Inspection

Check if the input power voltage is correct.

Check the compressor.

Check if the overload protector has tripped out.

Check if the internal temperature of the cooler is too high.

Check if the fan motor works properly.

Solution

Input the correct power voltage.

Replace the burned out compressor.

Reset the overload protector.

Improve the working environment to create better ventilation.

Replace the fan.

(C)

Explanation

There is an oil pressure fault or insufficient oil amount within the system.

A13

Possible Cause

No liquid flow or insufficient oil.

Oil pressure loss.

Oil pressure switch failure.

Flow rate switch failure.

Air penetrated into oil circulating system

Pump motor failure.

Oil viscosity is too high.

Inspection

Check if there is enough oil within the oil circulating system.

Long, thin and flattened oil hoses will cause oil pressure loss.

Please check if the value of oil pressure switch is within the designed specification.

If the pump motor fails, there will be no oil flow.

Check if there’s any air penetrated into the oil circulating system.

Check if oil viscosity is within the suitable range.

If all the above checked is all right, there is a chance of failure in oil pressure switch or the flow rate switch.

Solution

Supply more oil into the oil tank or the oil circulation system to the rated level.

Increase the diameter of the hose or shorten the length of hose to avoid oil pressure loss.

Reset the oil pressure switch to designed specification.

Replace faulty pump motor.

Please remove the air within the system. Please refer to 5-8 before operation.

Use oil with lower viscosity.

Replace faulty parts.

(D)

Explanation

There is a pressure fault within the refrigeration system.

A14

Possible Cause

Low or over charge of refrigerant.

Obstruction or leakage in the refrigerant system.

Condenser or air filter is dirty or cloggy.

Poor heat dissipation.

Fan failure.

Inspection

Check if the copper pipe near the low pressure side of the compressor is not cold.

Check if the fins of the condenser are not hot and the temperature of the dryer is too low.

Check if the air filter or the condenser is dirty or cloggy.

Check if the internal temperature of the cooler is too high.

Check if the fan works properly.

Solution

Please contact the refrigeration service technician for faults within the refrigeration system.

Clean the air filter and condenser regularly to improve the air dissipation, and remove any obstructers from air intake or

exhaust.

(E)

Explanation

The power phase input has been reversed.

A17

A41

A42

Possible Cause

Reversed phase of main power source.

Power source is single-phased.

Reverse-phase relay failure or temperature controller failure.

Inspection

Check if the power voltage input is correct.

Check if the power phase input is correct.

If the power phase input is correct, there is a chance of the reverse-phase relay or the temperature controller failure.

Solution

Reconnect the power cable with correct phase.

Three phase cooling unit should be connected to three phase power source.

Replace the faulty parts.

(F)

Explanation

Surface temperature of the compressor is too high.

A18

Possible Cause

Poor heat dissipation.

The cooler is not cleaned regularly.

Incorrect power voltage input.

Faulty compressor.

Inspection

Check if any air vent is cloggy.

Check if the power voltage and phase input is correct.

Check the starting condition of the compressor and the operating power.

Solution

Create better heat dissipation environment and maintain the cooler regularly.

Input correct power voltage and phase.

Replace faulty compressor.

(G)

Explanation

Liquid temperature sensor fault.

A21/ OPE

Possible Cause

Broken connection of the liquid temperature sensor.

Temperature control failure.

Inspection

Check if the connection of the liquid temperature sensor is broken.

If the connection is not broken, then there are chances of

temperature controller failure or sensor failure.

Solution

Reconnect the wire.

Replace the wire.

(H)

Explanation

The basic temperature sensor fault.

A22/ OPE

Possible Cause

The wire connection of the basic temperature sensor is broken.

The temperature controller failure.

Inspection

Check if the wire for basic temperature sensor still connected.

If the connection is not broken, then there are chances of temperature controller failure or sensor failure.

Solution

Reconnect the wire.

Replace the faulty parts.

(I)

Explanation

Liquid temperature is too high.

A31

Possible Cause

Liquid temperature exceeds 50°C.

The cooling capacity of the cooler is low.

Liquid temperature sensor failure.

Refrigeration system failure, either blocked or leaked.

Inspection

Check if the liquid temperature and ambient temperature exceed 50°C.

Check if the cooler works with the machine tools at the same time.

Check if the cooler unit is capable for the process load.

The cooper pipe near the low pressure side of the compressor is not cold.

The fins of condenser are not hot.

The temperature of the dryer is too low.

Check if the sensor functions properly.

Solution

Keep the liquid temperature below 50°C.

Please note that the cooler unit and the machine tools should start at the same time.

Replace the cooler unit with a larger cooling capacity.

Replace the liquid temperature sensor.

Please contact the refrigeration service technician for faults within the refrigeration system.

(1) Sudden stop during operation without alarm message shown:

?	?
Problem: Main power is input, but the cooler and the pump don’t work.
Situation	PV °C and SV °C not displayed.
Possible cause	The main power may not be properly connected, or the circuit breaker of the main power source is off. Control board failure.
Inspection	Check if the main power source is supplying the power properly. Check if the circuit breaker is on. If all the above is ok, there is a chance of control board failure.
Solution	Reconnect the main power source. Replace the faulty parts.
Situation	PV °C and SV °C display temperature: PUMP light is on.
Possible cause	Remote control is broken. * Magnetic switch is faulty. Incorrect power voltage input. * Pump motor failure.
Inspection	Check the remote connection. * Check the electromagnetic switch. Check the input power voltage. * Check the pump motor.
Solution	Reconnect remote control. Input correct power voltage. Replace faulty parts.
B) Problem: The pump is operating, and the oil flow is not working properly.
Situation	The oil flow rate is reducing and noise is created at the pump.
Possible cause	The tub clip of the oil pipe is not properly tightened. Insufficient oil within the oil tank. Cloggy oil tank. Oil circulating system and viscosity are not within the operating range. The activated of oil pressure regulating value due to oil pressure loss. Air penetrated into the oil circulating system.
Inspection	Please check if there is any leakage from joints to hoses due to loosing tub clip. Check if the oil viscosity is between 10-300cSt. Check if the oil filter is clogged by contaminants. Check if there is any air penetrated into the oil circulating system Check if there is any oil pressure loss. Check if the oil level within the tank is within the rated height.
Solution	Tighten the loose tub clip. Clean the oil filter. Increase the diameter and shorten the length of the oil hoses to avoid pressure loss. Fill in more oil into the tank. Please use appropriate oil. Remove the air within the oil circulating system according to 5-8 before operation check.
C) Problem: The pump runs properly; Cooling capacity failure.
Situation	The cooling system does not work. (The compressor does not work. )
Possible cause	The cooler stops working when the liquid temperature exceeds the set value. Failure of electromagnetic switch. Bad heat dissipation.
Inspection	Check if the liquid temperature reaches the set value. Check the electromagnetic switch. Check the internal temperature of the cooler.
Solution	When the liquid temperature reaches the set value, it is normal that the cooler stops functioning. Replace the faulty electromagnetic switch. Improve the working environment to create better ventilation.
Situation	The liquid temperature reaches the set value; the cooler unit still runs.
Possible cause	Overload cooling capacity. Bad heat dissipation. Refrigerant leakage. Temperature controller failure.
Inspection	Check if the targeted cooling capacity exceeds the cooler’s capacity. Check if the internal temperature of the cooler is too high. The cooper pipe near the low pressure side of the compressor is not cold. If all the above checked is all right, there is a chance of temperature controller failure.
Solution	Replace the cooler unit with a larger cooling capacity. Improve the working environment to create better ventilation. Replace the faulty temperature controller.
D) Problem: Sudden stop of the cooler during operating and an alarm signal is sent.
Situation	PV °C and SV °C lights are on but the cooler does not work.
Possible cause	The vibration of the machine tool will loose the connection wires. Remote control connection is out. Temperature controller connection is out or faulty.
Inspection	Check all connections. If all the connections are ok, then there is a chance of temperature controller failure.
Solution	Reconnect all the connections. Replace the faulty temperature controller.
Possible cause	The circuit breaker is off. The vibration of the machine tool will loose the connection wires. Remote control connection is out. Temperature controller connection is out or faulty. Power supply failure.
Inspection	Check if the circuit breaker is on. Check all the connections. Check power supply. If all the connections are ok, then there is a chance of temperature controller failure.
Solution	Reset the circuit breaker. Reconnect all the connections. Replace the faulty temperature controller.

Problem: Main power is input, but the cooler and the pump don’t work.

Situation

PV °C and SV °C not displayed.

Possible cause

The main power may not be properly connected, or the circuit breaker of the main power source is off.

Control board failure.

Inspection

Check if the main power source is supplying the power properly.

Check if the circuit breaker is on.

If all the above is ok, there is a chance of control board failure.

Solution

Reconnect the main power source.

Replace the faulty parts.

Situation

PV °C and SV °C display temperature: PUMP light is on.

Possible cause

Remote control is broken. * Magnetic switch is faulty.

Incorrect power voltage input. * Pump motor failure.

Inspection

Check the remote connection. * Check the electromagnetic switch.

Check the input power voltage. * Check the pump motor.

Solution

Reconnect remote control.

Input correct power voltage.

Replace faulty parts.

B) Problem: The pump is operating, and the oil flow is not working properly.

Situation

The oil flow rate is reducing and noise is created at the pump.

Possible cause

The tub clip of the oil pipe is not properly tightened.

Insufficient oil within the oil tank.

Cloggy oil tank.

Oil circulating system and viscosity are not within the operating range.

The activated of oil pressure regulating value due to oil pressure loss.

Air penetrated into the oil circulating system.

Inspection

Please check if there is any leakage from joints to hoses due to loosing tub clip.

Check if the oil viscosity is between 10-300cSt.

Check if the oil filter is clogged by contaminants.

Check if there is any air penetrated into the oil circulating system

Check if there is any oil pressure loss.

Check if the oil level within the tank is within the rated height.

Solution

Tighten the loose tub clip.

Clean the oil filter.

Increase the diameter and shorten the length of the oil hoses to avoid pressure loss.

Fill in more oil into the tank.

Please use appropriate oil.

Remove the air within the oil circulating system according to 5-8 before operation check.

C) Problem: The pump runs properly; Cooling capacity failure.

Situation

The cooling system does not work. (The compressor does not work. )

Possible cause

The cooler stops working when the liquid temperature exceeds the set value.

Failure of electromagnetic switch.

Bad heat dissipation.

Inspection

Check if the liquid temperature reaches the set value.

Check the electromagnetic switch.

Check the internal temperature of the cooler.

Solution

When the liquid temperature reaches the set value, it is normal that the cooler stops functioning.

Replace the faulty electromagnetic switch.

Improve the working environment to create better ventilation.

Situation

The liquid temperature reaches the set value; the cooler unit still runs.

Possible cause

Overload cooling capacity.

Bad heat dissipation.

Refrigerant leakage.

Temperature controller failure.

Inspection

Check if the targeted cooling capacity exceeds the cooler’s capacity.

Check if the internal temperature of the cooler is too high.

The cooper pipe near the low pressure side of the compressor is not cold.

If all the above checked is all right, there is a chance of temperature controller failure.

Solution

Replace the cooler unit with a larger cooling capacity.

Improve the working environment to create better ventilation.

Replace the faulty temperature controller.

D) Problem: Sudden stop of the cooler during operating and an alarm signal is sent.

Situation

PV °C and SV °C lights are on but the cooler does not work.

Possible cause

The vibration of the machine tool will loose the connection wires.

Remote control connection is out.

Temperature controller connection is out or faulty.

Inspection

Check all connections.

If all the connections are ok, then there is a chance of temperature controller failure.

Solution

Reconnect all the connections.

Replace the faulty temperature controller.

Possible cause

The circuit breaker is off.

The vibration of the machine tool will loose the connection wires.

Remote control connection is out.

Temperature controller connection is out or faulty.

Power supply failure.

Inspection

Check if the circuit breaker is on.

Check all the connections.

Check power supply.

If all the connections are ok, then there is a chance of temperature controller failure.

Solution

Reset the circuit breaker.

Reconnect all the connections.

Replace the faulty temperature controller.