Set hot water levels and use Boost

Use this guide to check how much hot water is ready and ask your tank to heat more. Boost is an extra heating request for when you need more hot water; it does not heat the water instantly.

You can use the buttons on the tank without the app. Choose the gauge instructions below, or the app instructions if you use it.

What does the hot water level mean?

The level shows the amount of usable hot water available, rather than its temperature. In the app, this is shown as a percentage. On the tank, it is shown by lights.

A full level does not mean a set number of showers. Tank sizes and shower flow rates differ, so notice how much water your household usually uses before choosing a larger Boost.

Check the lights on the tank

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

• Red lights show hot water that is ready to use.
• Green lights show the extra water the tank has been asked to heat. They turn red as that water becomes ready.

Each light represents about one tenth of the tank’s usable hot water capacity.

Use Boost on the gauge

1. Look at the red lights to see how much hot water is already available.
2. Press the up arrow once to ask for a small increase. Look for a green light above the red lights.
3. If you need more, press the up arrow again. Start with a small amount if you’re unsure.
4. Allow time for the green lights to turn red. The extra water is then ready to use.

Selected too much? Press the down arrow to lower the target. This reduces the amount still being requested; it does not cool water that is already hot.

If no green light appears, or it stays green much longer than usual without providing more hot water, follow Boost not working.

Check the level in the app

Open the Mixergy app and select your tank if you have more than one. On the tank’s main screen, look for the hot water percentage. The screen also shows whether the tank is heating and when its information was last updated.

If the information looks out of date, check the small Wi-Fi symbol near the top of the gauge:

• Blue: the tank is online. Close and reopen the app to check the information again.
• White: the tank is offline. Use the gauge for now and follow Check your tank’s connection status.

Use Boost in the app

1. On your tank’s main screen in the app, check the current hot water percentage.
2. Select Boost. Choose the hot water target shown by the app and confirm the request. Start with a small increase rather than selecting the maximum unless you need it.
3. Allow time for the water to heat. Check whether the available hot water level increases.

If you can’t find Boost or aren’t sure what the displayed target means, use the up arrow on the gauge instead. Don’t change unfamiliar settings to try to start a Boost.

Heating time depends on how much water you request and how your tank heats it. A heat pump for example generally heats more gradually than direct electric heating.

If Boost doesn’t seem to work

• The tank is already at the target: it does not need to heat more water to reach that level.
• The tank is running a cleansing cycle: this is an automatic hygiene cycle, during which Boost can be unavailable. Try again when it finishes.
• Boost fails in the app: try one press of the gauge’s up arrow. App requests need an internet connection.
• A green light appears but stays green: the request was accepted, but the water has not finished heating. If it takes much longer than usual, follow Boost not working.

Common questions

Should I always heat the tank to 100%?

Choose the amount you expect to need. You don’t need to select 100% for every Boost. It is more cost effective to select the amount you need without heating the whole tank.

Can I reduce a Boost after starting it?

Yes. Press the down arrow on the gauge to lower the target.

Can I use Boost without the app or internet?

Yes. Use the up arrow on the gauge. The app needs a connection to send a Boost request.

Does one light mean enough hot water for one shower?

No. Each light is about one tenth of the usable tank capacity. The amount needed for a shower depends on your tank and how much water the shower uses.

Why hasn’t the water heated immediately?

Boost asks the tank to heat; it does not provide instant hot water. Allow the usual heating time for your system. If the level does not increase after much longer than usual, follow Boost not working.