Ever wondered what the HT message on an A/C Service Cube means?

Ever wondered what the HT message on an A/C Service Cube means?

If you use a Cube air conditioning service machine you will probably have seen a variety of messages appear on the display, however, the one our customers quiz our technician about the most is “HT”. Here’s a quick explanation to help you understand what it’s all about.

“HT” actually stands for “Heater” - any the wiser now? Well, in the filling stage of using the Cube you have internal storage tank pressure; this is what is used to inject refrigerant into a vehicle (the compressor is only used for recovery). When the pressure drops to 5/6 bar, there’s not enough pressure to push it through the 6 metre hoses and the refrigerant flow stops, prompting a “HT” message to flash up on the screen. 


Ordinarily switching on the heater blanket to heat up the bottle to increase pressure and start the flow again would resolve the issue, however, the Cube doesn’t have one so you need to take the following steps instead. Disconnect the highside coupler on the vehicle, start the engine and air conditioning, then open the taps on the service cube.  Once the compressor is engaged it will suck the remaining refrigerant out to the value you have set in the programme. 


Troubleshooting insufficient pressure and the “HT” message

 • Keep the refrigerant level at about 3kg to create the required system pressure – once you are down to 1.5/2kg of refrigerant in the storage tank there won’t be enough to create the required pressure.

• If you have sufficient refrigerant and you are still having issues, check for cracks and/or squashed gaskets in the hose. Also check your couplers are not leaking.

• During recovery ensure you keep an equilibrium between high and low as imbalances can result in reduced tank pressure.  

Best practice is to purge the Cube’s cylinder after every job and make sure the waste bottle is empty at all times. We will show you how to do this in your Cube set-up training but if you have any queries please don’t hesitate to get in touch. 


 We are Europe’s leading supplier of air-conditioning parts for agricultural and construction vehicles. Search over 30,000 products by vehicle or part/OEM number and read other blogs on our website: www.apairltd.com 

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