Boost not working

Boost asks your Mixergy tank to heat extra hot water. If it doesn’t seem to work, start with the check below. You don’t need the app.

1. Try one Boost on the tank

Find the Mixergy Gauge, the slim black panel with lights and buttons on your tank.

Look at the red lights. They show how much hot water is ready to use.

Press the up arrow once to ask the tank to heat a little more water.

Look for a green light above the red lights. It shows the extra water the tank is being asked to heat. That light should turn red when the water is ready.

What happened?

• A green light appeared: the tank accepted the request. Go to “The light stays green” below.
• No green light appeared: go to “No green light appeared” below.
• The gauge worked, but Boost in the app didn’t: go to “Boost only fails in the app” below.

No green light appeared

Check which of these applies:

• The red lights are already at the maximum level: the tank is already showing its maximum hot water amount, so it cannot add another light.
• The tank is in standby: press the gauge’s power button once to wake it, then try the up arrow again.
• The tank is running a cleansing cycle: this is an automatic hygiene cycle. Boost can be unavailable until it finishes. If you use the app, check whether it shows this cycle.
• The gauge has no lights: check the tank’s normal visible power switch, if you can reach it safely. If it is on but the gauge stays unlit, ask for help below.

If none of these explains the problem, or the tank still won’t accept a Boost after the relevant check, use the help details below. Don’t keep pressing the up arrow.

The light stays green

A green light means the tank has a heating target; it does not mean the extra water is ready yet.

Allow the usual heating time for your home. A larger Boost takes longer.

• The light turns red: the extra hot water is ready. No further Boost check is needed.
• It stays green much longer than usual: check for a warning on your boiler or heat pump, if your tank uses one. If electricity for your tank is only available at certain times, it may have to wait for that supply.

If the light still stays green and you have no extra hot water, contact the team below. Tell them how long you waited and mention any warning.

The lights are red, but the taps are cold

Carefully check whether water from a normal hot tap gets warm, keeping your hands out of the flow until you know the temperature.

If the gauge shows several red lights but all your hot taps remain cold, follow No hot water or ask for help below. The problem may involve the plumbing rather than the Boost request.

Boost only fails in the app

If the up arrow on the gauge works, use it for now. Then check the small Wi-Fi symbol near the top of the gauge:

• White: the tank is offline, so it cannot receive an app Boost. Follow Check your tank’s connection status.
• Blue: the tank is online. Check that your phone has internet access, then close and reopen the app.

If app Boost still fails while the tank is online, check that you’ve selected the correct tank. Look for a cleansing-cycle message or another explanation in the app, and install any available app update.

Selected too much hot water?

Press the down arrow on the gauge to lower the target. See How to use the Mixergy controls for your hot water for more help.

Need help?

If you rent, contact your landlord or housing provider.

Homeowners can contact Mixergy’s Homeowners & Residents team on 01865 595 875, Monday to Friday, 9am to 5pm.

Tell them whether you used the gauge or the app, and what happened to the lights. If a light stayed green, say how long you waited. Include any app message or boiler/heat pump warning.

Common questions

Can I use Boost without the app or internet?

Yes. Press the up arrow on the tank’s gauge. Boost through the app needs an internet connection.

Why does the green light stay green after I press Boost?

It shows the water the tank has been asked to heat. Allow the usual heating time. A bigger Boost takes longer.. Ask for help if it stays green much longer than usual without providing extra hot water.

Can I reduce a Boost if I selected too much?

Yes. Press the down arrow on the gauge to lower the heating target. See How to use the Mixergy controls for your hot water for help.

Why is Boost unavailable during a cleansing cycle?

The tank is completing an automatic hygiene cycle. Boost can be unavailable until that cycle finishes. Try again afterwards.

Does one press provide enough hot water for one shower?

Not necessarily. One press asks for a small increase in hot water; the amount needed for a shower varies with the tank and how the water is used.

Related guides

How to use the Mixergy controls for your hot water

No hot water

Check your tank’s connection status