Dual-fuel heating and hot water

[Palmerlee]

Our first Autotrail motorhome is ordered, delivery expected in February '18.

 

Being a novice, I am trying to understand the features, one of which is the operation of the heating and hot water system. Truma dual fuel blown air heating and hot water heater are fitted as standard.

 

Does this mean than when hooked up on site we will be able to obtain sufficient heating and hot water from the paid electricity or is it likely this would need to be supplemented with gas?

 

Many thanks.

 

 

 

[Derek Uzzell]

It might be useful if you said which model of Auto-Trail motorhome you’ve chosen, just in case another forum-member has one and can provide ‘hands-on’ advice.

 

I assume a “Truma dual fuel blown air heating and hot water heater” means a Truma “Combi” 4E or 6E appliance as described on Pages 28-31 of this 2018 Auto-Trail handbook

 

https://www.auto-trail.co.uk/assets/downloads/files/8200bdf17517f61ab778e537914ca4ec35488681.pdf

 

When a motorhome with this heater is hooked up to a 230V power-supply, the supply can be used to heat water or heat air + water. A Combi’s 230V heating-elements have an output or 900W or 1800W - this will be sufficient to heat water but will only provide ‘background’ blown-air heating. To circumvent this limitation the heater can be operated in ‘mixed mode’ where blown-air heating will be via 230V unless the heater cannot adequately maintain the air-temperature the user has selected, at which point the heater’s gas-burner will light to supplement 230V operation.

 

This time of year in the UK it’s quite likely that operating a Truma Combi solely on 230V would not provide enough blown-air heat for the motorhome to be comfortable inside during the day, though it might be adequate at night when people are in bed.

 

For air-heating on campsites with a ‘pay’ 16Amps 230V power-supply (if the cost concerns you) you might consider using a 230V fan-heater or electric radiator that has a higher output than the 1800W (8Amps approx.) maximum of the Combi.

[Palmerlee]

Derek Uzzell - 2017-11-15 9:03 AM

 

It might be useful if you said which model of Auto-Trail motorhome you’ve chosen, just in case another forum-member has one and can provide ‘hands-on’ advice.

 

I assume a “Truma dual fuel blown air heating and hot water heater” means a Truma “Combi” 4E or 6E appliance as described on Pages 28-31 of this 2018 Auto-Trail handbook

 

https://www.auto-trail.co.uk/assets/downloads/files/8200bdf17517f61ab778e537914ca4ec35488681.pdf

 

When a motorhome with this heater is hooked up to a 230V power-supply, the supply can be used to heat water or heat air + water. A Combi’s 230V heating-elements have an output or 900W or 1800W - this will be sufficient to heat water but will only provide ‘background’ blown-air heating. To circumvent this limitation the heater can be operated in ‘mixed mode’ where blown-air heating will be via 230V unless the heater cannot adequately maintain the air-temperature the user has selected, at which point the heater’s gas-burner will light to supplement 230V operation.

 

This time of year in the UK it’s quite likely that operating a Truma Combi solely on 230V would not provide enough blown-air heat for the motorhome to be comfortable inside during the day, though it might be adequate at night when people are in bed.

 

For air-heating on campsites with a ‘pay’ 16Amps 230V power-supply (if the cost concerns you) you might consider using a 230V fan-heater or electric radiator that has a higher output than the 1800W (8Amps approx.) maximum of the Combi.

 

Thanks - very helpful. The model is the Imala 730.

[crocs]

Derek's explanation is sound.

 

I have a Frontier that's slightly longer than yours and, at night in really cold weather, I use the electric only mode at low setting which keeps the bedroom comfortable when the dividing door is closed. It tends to need mixed mode during the day.

[bolero boy]

the latest CP Plus versions of the Combi systems are a lot better at making the electric neating 'go further'..

they have a fan where the speed can be set (Eco or High)....in the past, the fan was only proportional to the heat produced.....and on electric (900w or 1800w) this usually wasnt very good and not powerful enough to distribure warm air all around the van.

the HIGH fan speed has done much to improve things and an 1800w setting with the HIGH fan speed should keep things warm enough unless it gets really cold and you are warming up from cold, in which case Mixed Mode is better.

of course, if you are trying to heat water AND power heating at the same time, the finite power of 1800w will stuggle to do both jobe, normally water will just take far longer than the normal 20 mins or so to heat fully.

a bit of practice and experience will help, youll be fine.