Diamond Dave

See other Advice articles filed in ‘General motorhome advice’ written by Diamond Dave
Practical Motorhome's tech guru Diamond Dave is talking space heaters, to help keep you cosy wherever and whenever you go touring in your 'van

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.
Share with friends

Follow us on

Most recent motorhome reviews

The Practical Motorhome Mercedes-Benz Marco Polo 250d Sport Long review – 1 - The Mercedes-Benz Marco Polo 250d Sport Long is priced from £56,670 OTR, £63,990 as tested (© Phil Russell/Practical Motorhome)
The Practical Motorhome Chausson Welcome 711 Travel Line review – 1 - The new Chausson 711 is being sold in Welcome Travel Line spec only (© Peter Baber/Practical Motorhome)

Swift Rio 325


The Practical Motorhome Swift Rio 325 review – 1 - The 2018 Swift Rio 325 is just 5.99m long and has a licence-friendly MTPLM of 3500kg (© Phil Russell/Practical Motorhome)
The Practical Motorhome IH N-Class 630 RLS review – 1 - The IH N-Class 630 RLS is priced from £73,995 OTR for the 130bhp variant and from £76,490 OTR for the 180bhp version – we're testing the latter (© Gentleman Jack/Practical Motorhome)
The Practical Motorhome Marquis Majestic 196 review – 1 - Fitting six berths and six travel seats into a 3500kg motorhome is no mean feat – does it work? (© Phil Russell/Practical Motorhome)
The Practical Motorhome Swift Bessacarr 597 review – 1 - The ’van tested has an MTPLM of 3850kg, but there is a version with a 3500kg MTPLM (and a lower payload) – read more in our Swift Bessacarr 597 review (© Peter Baber/Practical Motorhome)