Mixergy Cube X FAQ

Mixergy Cube X is a thermal store. It stores heat inside the unit, then uses that heat to warm fresh mains water when you open a hot tap.

The stored heating water and the fresh tap water follow separate paths and do not mix. This differs from a conventional hot water cylinder, which stores the water supplied to the taps.

How stored heat becomes hot tap water

A conventional cylinder stores the hot water supplied to the taps. Cube X keeps heat in a separate store of heating water. When a hot tap opens, fresh mains water passes through a heat exchanger, which transfers heat between the two water paths without mixing them.

Sensors measure the available heat so the controls can prepare an amount that suits the household. Cube X can heat the top of the store first, making useful heat available before the whole store is heated. This helps avoid storing more heat than you expect to use.

Everyday use

• Leave Cube X switched on so its controls can operate.
• Notice the gauge level that normally provides enough hot water for the household.
• Use a suitable heating plan and request a small Boost when extra water is needed.
• Keep the unit accessible for servicing. Do not open covers or alter pipework.

When to ask for help

If you rent, report a leak, recurring loss of hot water or a fault message to the landlord or housing provider. Homeowners should contact the installer. Report unusual noise or repeated changes in water temperature too.

For smoke, fire or immediate danger, leave the area and call the emergency services. Use the urgent repair route if equipment appears unsafe. Do not try internal controls while waiting for help.

Common questions

What does the level mean, and how do I request more hot water?

The gauge and app estimate how much usable hot water the stored heat can provide. The percentage is not the amount of water physically inside the unit. Fewer than ten red lights can be enough for your needs.

Find the gauge, the panel with lights and up/down buttons on the unit. Press the up arrow to request a higher level. Green lights show the extra amount requested and turn red as it becomes ready. Boost asks Cube X to store more heat, so allow heating time.

If you use the app, sign in and select your tank, then choose Boost on its Controls or Hot Water screen. See Set hot water levels and use Boost for the steps.

Do I need to adjust the settings every day?

No. Leave Cube X switched on and use a suitable manual schedule or Mixergy Flex. Flex is automatic scheduling that learns when the household uses hot water. Use Boost for unexpected extra demand. See Set schedules and smart control if you manage the settings yourself.

How is water hygiene managed?

The stored heating water is separate from the fresh water used at the taps. Cube X is designed and controlled for this arrangement. Do not change temperature, hygiene or installer settings without advice; ask the installer or housing provider if you have a concern.

What noise should I expect?

Cube X has no integrated compressor or fan, so normal operation should be quiet. Some pump or pipe noise elsewhere in the system can still be heard. Report new loud or repeated unusual sounds.

What should I do about low flow or the wrong water temperature?

If little or no water comes from a hot tap, check a cold tap too. This helps distinguish a supply problem from a hot-water problem.

• Hot and cold taps are affected: check your water supplier’s outage information or ask the housing provider about a supply problem. If no water is available anywhere, contact them.
• Only hot taps are affected: report this to the installer or housing provider. Tell them which taps are affected and when it started. Do not open covers or operate valves.

If flow is normal but the water is too cold, note the gauge level and whether heating has been requested. Allow the usual heating time if more heat is being prepared. Report recurring cold water or a fault message.

If water is unexpectedly very hot or risks scalding, stop using the affected outlet and seek urgent help. Do not test it with your hand or change internal controls. The installer needs to check the temperature controls.