Using your combi-heater in the winter

One of the joys of owning a motorhome is being able to get away in the winter months.

But keeping warm – and making sure the water in the heating system doesn’t freeze – are key priorities when the mercury dips.

It is perfectly possible to ensure the water in the heating system or vehicle does not freeze and to heat your motorhome when there is no water in the boiler.

According to Truma, the leading manufacturer of caravan and motorhome accessories, the heating will always be active if your vehicle has fresh water.

If the FrostControl (FC) is exposed to an ambient temperature of at least 3C, the water stays in the system and the FC remains closed. However, it is vital to remember to measure the temperature directly at the FC and to ensure that only the water runs out of the combi when the FC is open.

Before you head off on the road, check whether or not the fresh water tank and all water pipes run empty – it depends on how the vehicle manufacturer has installed the water supply.

The lowest room temperature can be set at 5C, but if this is not enough to heat the FC you can set it higher.

If you have the Truma CP plus, you can increase it by 1C, while if you have the CP classic, you change the temperature via the two rotary knobs – level 1 is 5C and it goes up to level 5, which is about 30C. Level 2 should be fine to keep the FC closed, but this is recommended only during a journey; it will not keep your vehicle frost free in the winter.

It is possible to operate the combi if you travel without water in the system, but if you do this, set it as only room heating because the water heating programme must remain inactive.

The water tank of the combi must be emptied correctly. Because residual water in the combi can get hot very quickly, the water vapour is likely to irritate the heater’s temperature sensors. If this happens, you’ll get a warning message.

If you use the vehicle without fresh water in the winter months, leave the FC open so any remaining water in the system naturally falls away when the vehicle is being driven.

Truma also recommends that motorhome owners alternate between the different modes, rather than sticking to one option for several months. This will help to prevent condensation in the exhaust pipe, which could affect the heating system.

We wish you safe, enjoyable and warm trips away this winter.