Unless Alde had altered their system, on loss of 12 volts, such as when coupling up to tow, only the "clock" defaults so losing the time.
No other of the client setting are lost, such as temperatures and timings, only the present time. You need to reset the clock, unless it has a backup option.
Though even just this is IMO a mega pain where it is so easy to provide the optional battery support, or with the older system a back up 12 volt feed; amazing all van builders don't simply include it as standard.
On the OP's point. The Alde boiler makes a heating fluid and the fresh water hot, it needs a pump to then circulate the heating fluid around the van. The Alde system controls when that circulating pump needs to be run, completely automatically, in response to your set temperature, the van's thermostat sensing of the internal space temperature, and the daytime and night settings, if you opt to programme these. You don't swich the pump on or off, the Alde system makes those decisions to meet your settings.