truma combi heater

[le canichot depang]

Our motor-home has the new truma combi 4e heater, it is brilliant with the exception of one thing. From what we can comprehend after reading the instruction manual from front to back (and over again) there is no way to operate it as a heater using electric only, you can use the heater on gas only and without water in the boiler but if you are connected to an electric supply you can only start the heater with gas and electric combination. Don't get me wrong it is a good system, both gas and electric are used to initially boost the temperature, then the gas cuts off and the electric maintains the temperature set by the thermostat, thus cutting down on the amount of gas you use, however what happens if you run out of gas? (I know you should always check that you have a spare bottle and enough gas available), but it might just happen that you run out, then you will have no heating (if you turn it off) until you again have a gas supply, maybe this might be addressed in future models - unless we have read it completely wrong in which case we would gladly be enlightened on the subject. *-)

[Brian Kirby]

Try this link.  You may have to "allow pop-ups" to get to the download.  http://tinyurl.com/8hdzm2

However, you should be able to download to your computer a multi-language .pdf file of the Operating Instructions for the Combi 4e.

In this you will find instructions for using the heater.  According to these, there is a rotary switch that allows the selection of 900W or 1,800W electric operation, gas operation, or mixed operation.  It is clear from these instructions that the unit can be operated on electricity alone.

If yours can't, it would seem either the installation is at fault, or you have a different version of the heater.

[le canichot depang]

thanks Brian, think we've worked it out now, a bit complicated for us simple islanders 8-)

[Derek Uzzell]

Judy:

 

There's a danger with these heaters is to link mentally, on a one-for-one basis, the 5 switch-settings on the Power Selector Switch with the similarly-positioned 5 switch-settings on the Control Panel. To appreciate how these heaters operate it's simpler to think of the Power Selector Switch and Control Panel as being completely unrelated.

 

As Combi E's can run on gas and/or 230V, the first thing that needs to be decided is which of these power-sources you want (or are able) to use. That's what the Power Selector Switch is for.

 

The Power Selector Switch's 5 settings are (top to bottom)

 

A: 230V-power only - 1800W

B: 230V-power only - 900W

C: Gas-power only

D: 230V(900W) + gas

E: 230V(1800W) + gas

 

If no 230V power-supply is available, or the 230V power-supply is insufficient to provide 900W (ie. below 4A), then you'll have to choose Option C - the "Gas-power only" setting.

 

If a 4A 230V power-supply is available, then you can choose Option B.

 

If the 230V supply can support an 8A demand, then you can choose Option A.

 

If you believe that the 230V supply alone will be inadequate to provide the heating you require (eg. blown-air heating during very cold weather), then you can choose Option D or Option E according to the Amperage limit of the 230V power-supply.

 

Once you've decided on the Power Selector Switch's setting, you can move on to the Control Panel. This has a rotary 1-to-9 knob that relates (indirectly) to the room temperature in the motorhome's living area. The higher the chosen number the harder and longer the heater will need to run to reach and maintain the desired room temperature.

 

The Control Panel also has 5 switch-settings. These are (top to bottom)

 

F: Water heating only - Maximum water temperature = 60°C

G: Water heating only - Maximum water temperature = 40°C

H: Heater OFF

I: Blown-air heating only.

J: Blown-air heating + water heating to 60°C

 

Some examples:

 

Options B & G - The heater will enter water-heating mode using 900W of 230V power. When the water has reached 40°C the heater will shut down.

 

Options A & I - The heater will enter blown-air mode using 1800W of 230V power. When the room temperature has reached the level chosen via the Control Panel's rotary-knob the heater will shut down completely irrespective of the temperature of any water inside it.

 

Options D & J - The heater will enter blown-air mode using 900W of 230V power, plus gas assistance as and when necessary. When the room temperature has reached the level chosen via the Control Panel's rotary-knob the heater's blown-air fan will shut off but water-heating will continue until the water temperature has attained 60°C.

 

That was just a broad-brush outline of how a Combi-E (and its C-6002EH predecessor) functions. Plainly, when the appliance is placed in "Mixed Mode" (Option D or E) and Option J is selected, operation becomes complex as the heater will be juggling air and water temperatures, blown-air fan speed, gas-burner output, and 230V and gas choice. As one can't control how it does this, my own philosophy is not to agonise over exactly what it's up to but just let it get on with it.