I frequently get asked to check the mains elements in Truma C series heaters because of so-called ‘poor performance’.
The truth is that they are relatively low power units at 900 Watts per element, giving two electric settings of 900W or 1800W. This level of heat generation is not going to heat a six-metre-plus motorhome very quickly, especially if the ambient temperature is around freezing or lower.
The sensible way to run such a system is to use either gas or gas and electric to get the room temperature up to a comfortable level, then the electric option should be able to maintain the temperature in the ’van.
How wet heating systems work
The Alde wet heating system is similar in operation to a domestic central heating system in that the heat source (gas or electric or both) heats water, which is circulated through pipes to radiators positioned around the motorhome. Now, obviously, this isn’t going to give instant heat output, as the circulated water (really a water and anti-freeze mixture) has to be heated up first before it can dissipate its heat through the radiators.
I have also heard quite a few motorcaravanners bemoaning the Alde system’s gas consumption, but size for size, it should be no worse than any other type of heater. The usual explanation is that they are heating a large motorhome, often more than eight metres in length, to high levels in very cold ambient temperatures. I know of one couple who used a full 11kg cylinder of gas in 24 hours, but the outside temperature never got higher than -5C and the internal temperature of their nine-metre motorhome was more than 25C.
Batteries can get flattened
Some users believe that Eberspacher and Webasto diesel heaters fire up and work better on mains hook-up. This could be because the wiring to the heater is too thin and/or too long a run. The result is voltage drop at the heater causing a low-voltage failure.
They also have a reputation for being noisy, but this is usually because the system installer has not used the appropriate silencers for intake and exhaust.
Modern heating systems and CO
Another issue I often see is people afraid to leave a gas-fuelled heater running overnight for fear of carbon monoxide poisoning.
All heating systems used in motorhomes these days should be room sealed; this means combustion air is drawn in from outside the motorhome and exhaust air is expelled to the outside. There should be no need to worry – all properly fitted heating systems can be safely left running overnight.
The best advice for anyone having difficulty with a heating system has to be RTM (read the manual); most problems will be solved by applying this simple rule.
A keen motorcaravanner, Practical Motorhome’s technical expert Diamond Dave runs his own leisure vehicle workshop. Find out more at Dave Newell Leisure Vehicle Services.
All properly fitted heating systems can be safely left running overnight