Cambridge CNC Milling Machine Cooler repair

December 2025 Cambridge Daikin Chiller repair

We have Successfully carried out a repair to this customer’s CNC milling machine’s Daikin oil cooler in Cambridge. The chiller last had attention over 3 years ago for a gas leak and repair. This Manufacturing facility relies on its mm Precision during the drilling and cutting processes, both of which require coolant to be passed around the machine, which picks up heat as it goes. The Daikin chiller will then circulate the coolant and bring it back down to ambient temperature to maintain the steady and precise tolerances.

Our team of Refrigerant Engineers Were called in by the facility management team to investigate and remedy the issues with the Chiller, which was currently circulating temperature back into the CNC machine at 40degC causing havoc with the tolerances.

Initial Assessment

Upon arrival, we found the Daikin Chiller operating but with little effect, interrogation of the controller showed that the compressor was calling for 100% operating, sensor readings for coolant in and out showed that actual cooling was only 0.1degC. The condenser fan was operating and no error codes presented. The compressor itself was becoming very hot, the suction line also felt warm, all of which was indicating a reduction in refrigerant within the system. This was confirmed by connection manifold gauges and using external probes to determine the Super heat (currently 45deg).

Identifying leak location.

Whilst the system still holds an amount of refrigerant gas we passed an electronic leak detector over various areas of the system in attempt to locate the refrigerant leak. Full strip down of the panels revealed the entrance point of the condenser coil has oil development. The leak detector is hinting around the area but the exact location must be identified with a leak detection spray.

Chiller Repair Procedure 

The remaining refrigerant contained within the system has to be recovered and weighed to compare against the data plate of the system determining refrigerant loss. It was found to have lost around 600g of refrigerant. The system is then pressure tested using Oxygen Free Nitrogen (OFN), once the pressure has increased the leak detection spray is able to identify the exact position of the leak, which was found to be in an area of copper passing through the surrounding steel plate of the condensing coil.

Repair procedure

Where the coil passes through the steel plate it becomes impossible to braze. Our options in this instance are to re route the pipework around the damaged section / install a new section of copper and braze back in further along the coil / replace the condensing coil / cut around the plate and expose the leak to allow repair. In this instance due to space constraints and the lack of readily available spares we chose to cut away the plate and attempt repair. Using a grinder and a multi tool we carefully cut away the steel plate, taking our time not to damage any other sections of the copper pipework. Once exposed the leak point became obvious and accessible. Passing nitrogen through the system during the braze procedure prevents oxidisation within the pipework.

Testing & Confirming repair

Following the braze procedure the system is then re pressure tested and and checked for any other leaks. Once the pressure test is deemed to be holding the nitrogen is let go, the system is then Vacced to 2 torr and recharged with virgin R410a refrigerant. The system is then powered back up and ran through is test modes.

Repair result.

Interrogation of the controller now shows even at 70% compressor output the cooling work done is now closer to 2degC. Superheat is now 15deg and the returning suction pipe temperature is no longer warm / hot and compounding the previously overheating compressor. No further issues found.

Coolant / Oil Chillers

There are numerous manufacturers of the coolant chillers, they are often installed within the CNC machines themselves which restrict service access, where possible these can sometimes be repaired in situe, otherwise they need to be powered down and removed from the CNC machines using cranes when available on site.

Looking for Commercial Refrigeration Repairs?

If your coolant systems require technical fault identification or service, contact Davenport Cooling Services Limited for professional assistance. Our Engineers are available for 24 hour call out for emergency repairs and service across Leicestershire and the East midlands but also in this case Cambridge!