How does the Duo storage heater work and how does it work with a central PW4 timer?

The DuoHeat storage heater is made up of two heat sources, a storage brick core heated up overnight using cheap off-peak electricity, and an automatically controlled radiant front panel which provided top-up heat using the daytime supply if the room temperature cannot be met by the storage core.

See Duo-N User and Install guides and Quick Start guides.

See Duo-i User and Install guides and Quick Start guides.

We also have help pages for the RXPW4, RXPW4N and RXMBS4 timers and how to set up the timer itself.

The background stored heat is adjusted by following this video guide.

The front radiant panel can be turned up or down to suit your desired room temperature using the plus and minus buttons.

Each red bar on the heater represents 1 degree of heat, starting with 1 bar = 18C, 2 bars = 19C and so on. In the example below, 4 bars are lit = 21C target room temperature, if the storage core cannot deliver it, the radiant front panel will aim to do so.

There was an option to use an external 4 zone timer controller with the Duo heaters, to time control the radiant front panel into the following modes:

Comfort mode (SUN symbol on timer) - Radiant front panel working to how you set it on the LED bargraph on top of the heater (as shown above). Stored heat setting is not affected. To see how to change the stored heat click here.

If you don't want to use the timer, turn the timer dial to the SUN position and just use the controls on your Duoheat storage heater manually.

Timer modes:

Setback mode (Moon symbol on timer) - Radiant front panel is reduced by 2C temperature and keypad on heater locked by the timer (green LED on lock symbol). Stored heat setting is not affected. To see how to change the stored heat click here.

Frost mode (if set by just turning the heater front panel to blue LED manually) -front panel will only come on if room drops below 14C (16C on older Duo-i) and storage heat unaffected. If the frost signal is sent from the timer however (snowflake symbol on timer and frost blue light and a green lock light on heater), the front panel is off and the stored heat reduces to store enough heat just for 14C frost protection.

If the timer is set to "off" mode (power symbol on the timer dial), then both the radiant front panel and storage core are switched off completely. On the DuoHeat radiator, none of the bar LEDs are lit and the lock LED is green, showing the timer has locked the heater control. If you want to alter the heater settings, you will need to turn the timer dial to the SUN position again.