Bailey • Retreat • Sycamore • 2012

Climate class SN (which Dometic calls 'Extended Temperate') means the fridge is designed to work reliably when the air temperature is from +10°C up to +32°C (taken at the bottom vent grille, outside the vehicle).

In a hot summer the outside temperature often reaches about 32°C - the top of the fridge's rated range - and once it climbs higher, the temperature inside the fridge will inevitably rise. An absorption fridge needs a heat source to move its refrigerant around the cooling unit (which is why it can run on 12V, 230V or gas), so it has to get rid of the heat from its power source as well as the heat drawn out of the food compartment.

To help it in hot weather: park where the fridge vents get as much shade as possible during the day; unclip the outside vent grilles to improve airflow; and if you regularly travel somewhere hot, consider having a ventilator kit (a fan fitted behind the fridge) installed to boost the airflow - Dometic lists these among its accessories.

The RM(X)8xxx range can take an S+ signal on its control board, which lets it pick solar-supplied DC power when it's available. For this you need a solar regulator from Dometic's Büttner range that has a signal output cable, wired to S+. The panel charges the leisure battery (or batteries), and whenever the regulator signals that solar power is available, the fridge gives it top priority in AES (automatic) mode.

In automatic mode the fridge chooses its energy source in this order: solar DC first, then mains AC, then ordinary 12V DC, and gas last. Most AES set-ups take their 12V feed from the vehicle's starter battery, with the alternator's D+ signal allowing DC operation; to use the S+ signal instead, you'll need a changeover switch so the 12V heating element is supplied from the leisure battery rather than the vehicle battery.

On 12V the element is rated 120-190W, so the fridge draws a continuous 10-15A on DC - more than most vehicles' leisure batteries can sustain for long, which is why this solar/DC mode tends to be used where the fridge is fitted in a beach hut or similar off-grid building. Bear in mind that changing the vehicle's wiring could void your warranty - Dometic advises checking with your dealer first.

Dometic's 2023 'New for old - simply swap' guide covers both its absorption and compressor fridges, showing which current models replace older ones. It's available from the catalogues section of Dometic's website.

Check the fuse in the mains supply and replace it if it has blown, and make sure the vehicle is actually plugged into a mains supply. If both are fine, the AC heating element may have failed - that needs an authorised Dometic service centre.

Possible causes, and what to do: the vehicle's own fuse has blown - replace it (see the vehicle's handbook); the vehicle battery is flat - test it and recharge it; the ignition is off - switch it on. If the fuse in the fridge's DC cable has blown (the fuse on the relay) or the DC heating element has failed, contact an authorised Dometic service centre.

Check the gas cylinder isn't empty (change it if it is) and that the gas valve is turned on. If air has got into the gas pipe, turn the fridge off and on again, repeating this three or four times if needed; if a gas hob or cooker is fitted, switch that on, then try the fridge again if needed.

The mains voltage is too low. The fridge switches back to mains by itself once the supply voltage recovers.

Work through the likely causes: the cooling unit isn't getting enough air - make sure the outside vent grilles aren't blocked; the evaporator has iced up - check the door shuts properly and the seal is seated and undamaged, then defrost the fridge; the temperature setting is too warm - turn it to a colder setting; it's very hot outside - take the vent grille off for a while so hot air can escape faster; too much food, or too much warm food, went in at once - take some out, and let warm food cool before putting it back; the fridge was only switched on recently - give it four to five hours, then recheck the temperature.