Truma heating - gas/electric mix

I think most people use the heating on electric when connected to an adequate EHU supply and may use gas as well if it’s very cold or a quicker warm up is required. There’s no other reason to use a mix. Gas alone is used when no EHU is available.

We have only rarely used gas for heating in any of our vans over the years and find electric alone is fine.

We have Truma Heating/Water in our caravan which we use all seasons and unless of a site power cut (once) ,have only ever used it on EHU normally on EL1 eco,unless really cold then we use EL2  and in the four years it has been plenty warm enough,

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We always run ours on Mix 1 if only 10amp or Mix 2 if 16 amp

Is there a thermal cutout switch on the unit? This pops out/trips if you try to run the unit with no water. We had the same problem just find it and push it back in.

We use very little gas, usually only for cooking as we're always on EHU, once warmed up then it keeps us warm on the 0.9Kw setting. 

We only use 'mix' if its very cold when arriving at a site.

At other times we tend to put it on the higher electric setting and the higher fan until the van heats up then reduce both once warm.

Gas only we have only used if we are not on EHU. 

With a MH the habitation part will usually get some of the heat from the cab heating while driving so the back of the van isn't as cold as a caravan when you stop. 

Thanks to all that have so kindly replied to my question so far. 

We have always powered the heating on Elec 2, even throughout the night and up until last week have had no problems. It appears that the outside temperature dropped significantly that night i.e. 0 to 2 degrees, could this mean that the system had to work extra hard to try and maintain an internal temperature of 15 degrees (which is what we required) and as such overheated and blew the fuse?

If we had the setting on Mix 2 then would that have called in the Gas to provide extra power to support the electric? 

Sorry if I seem a little stupid here but I’m keen to be clear on how I should manage the heating to ensure this doesn’t happen again. 

 

the mix setting obviously uses both electric (setting 1 for 900w and 2 for 1800w) and gas, with the gas power being self regulating to support the electric input...the lower setting 'might' require more help from the gas in the warm up phase.

a combi 4e can use upto 4kw of gas heating in gas only mode but only supplies up to 2kw of gas in mixed mode, giving a max combined output of 2900w on mix 1 or 3800w on mix 2.

a combi 6e can use upto 6kw of gas heating in gas only mode but only supplies up to 4kw of gas in mixed mode, giving a max combined output of 4900w on mix 1 or 5800w on mix 2.

the gas input tnrottles back as the requirement for heat reduces leaving just electric to maintain heat, with no switching required.

mixed is a very useful mode setting when just arriving on site in chilly weather and looking for a quicker warm up.

the electric settings might take a while longer to warm through a cold van but in other circumstances it will be fine when on ehu.

gas only when not on ehu (same with fridge).

good luck.

Thanks

Once again thanks for the replies, very helpful.

Im thinking that this weekend we’ll keep it on Mix 2 as it’s supposed to be a chilly one, albeit dry and sunny. 

This way we can be sure that during the night when it gets really cold, it will call for Gas as and when needed, reducing the strain on the electric. 

Does this sound sensible or should we use it on Mix 1? 

 

I've never felt the need to have it on 'mix' overnight.

We live in Scotland were we've been away with temps at - 8c overnight, with the heating on electric 1 set at 16c. It doesn't struggle to heat the van, once its heated up. 

During the evening we have it set to 20c but reduce it down at bedtime or its too hot.