# The workings of heater systems?



## Mick757 (Nov 16, 2009)

Can anyone briefly expalin OR offer a link to how heating systems generaly work?
Ive seen what look like 'regular' gas heaters installed in vans. eg Truma etc. Do these just kick heat out of this unit, or also send 'blown air' round the van? Do they work on gas AND leccy (230v and battery)?
I saw some kind of heater at the weekend that was just like a boiler, stashed under a seat. This was said to be for the blown-air heating, but will it have also done the hot water?
Sorry for the seemingly dumb questions, but the bloke showing me didnt seem to know that much more than myself.


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## richardjames (Feb 1, 2006)

There are some heaters that run off the engine cooling system and can heat the domestic water and/or provide heating for passengers whilst on the move and are usually under a front seat


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## Rapide561 (Oct 1, 2005)

*Heat*

Hi

Here are a few pointers for you.

Some Truma heaters can run on gas or electric or both at the same time. The clue is the model name. My boiler is a Truma Combi 6E. The "E" signifies it can take electric power, in addition to gas.

At various locations in my motorhome are circular outlets - a bit like the vents on a coach - you know, the ones above each seat next to the reading lights. These Truma outlets carry warm air generated by the boiler.

If you have a particular Truma boiler number, such as Combi 6E, C6002, C6002 EH, I might be able to help a bit more.

Russell


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## dovtrams (Aug 18, 2009)

could i also ask a heater question on this post. for the first time today, i emptied my heater using the yellow lever as it is likely to be minus something tonight. when i want to fill it up again, is there anything special you have to do?

dave


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## Rapide561 (Oct 1, 2005)

*Water*

Dave

By lifting the yellow lever, you have drained the boiler of it's water contents. To refill, close the lever, turn on the hot tap and this will cause your water pump to pump water from the main tank on the van to the Truma.

Have you just emptied the boiler or drained the van? By draining the van, I mean emptying the fresh water tank and leaving all taps in the open position to ensure there is no residual water in the pipes?

Russell


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## midlifecrisismil (Sep 27, 2009)

:? I am reading all these posts with fascination.
Is there a beginners/dummies class in motorhoming? I have just got our brochure out to see what Truma we have in Herman and it seems that ours is just run off gas so I have learnt something.
We have drained down Herman (by opening all the taps under him) but our Truma drain thingy is red not yellow so :? 
I have another question but I know that I am not aloud to hijack topics (after being told off) so I will ask it on a different post.


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## dovtrams (Aug 18, 2009)

russel

yes, i have drained everything, fresh water tank empty, waste tank empty and taps have been open all day, no more water. thanks for the advice.

dave


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## Rapide561 (Oct 1, 2005)

*Refilling*

Dave

When refilling....

1) Ensure the pump is off
2) Ensure the fresh tank drain tap - if fitted - is closed
3) Close all taps
4) Fill the fresh tank. 
5) Close the boiler train valve
6) Switch on the pump main switch
7) Open a cold tap SLIGHTLY to get water through - not too much opening though or you might get a bit of a splutter and get wet. 
8) Open a hot tap and this will force water into the boiler. 
9) Top up the fresh tank to replace what has just moved to the boiler.

That's how I used to do it.

In extreme weather, remove the shower head as quite a bit of water could be trapped in there.

Russell


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## Mick757 (Nov 16, 2009)

Many thanks Russel. I dont have a particuar boiler for specifics - yet, but am i free to ask further of you come the time, as you appear to know what youre about?

Mick.


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## Grizzly (May 9, 2005)

I've just posted the link on another thread but Truma UK do a list of useful leaflets and manuals to download. One of them has a parts list and prices which we've found useful.

http://www.trumauk.com/service.asp

G


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## Mick757 (Nov 16, 2009)

Thanks Grizzly, ill look at that. Though, my main gist was the way different heaters work. eg. some (i think) do 'blown air', and some dont. Are the latter phasing out, or are both types still popular. Is one type favoured over the other etc etc.? Im compiling a list of requirements for my first van, and want to know which heating system to look for combined with the style of van i now know i want.

Mick.


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## JeanLuc (Jan 13, 2007)

Mick757 said:


> Thanks Grizzly, ill look at that. Though, my main gist was the way different heaters work. eg. some (i think) do 'blown air', and some dont. Are the latter phasing out, or are both types still popular. Is one type favoured over the other etc etc.? Im compiling a list of requirements for my first van, and want to know which heating system to look for combined with the style of van i now know i want.
> 
> Mick.


There are three basic types of heating used in motorhomes; two are primarily gas heaters, and the third is diesel powered.

Blown-air heating, which is typified by the Truma system. The combi series of Truma (mine's a C6002) is both a space and water heater. Some work on gas only, others have an electric element too, either as an original fitting, or as an after-market collar (a bit like an electric blanket on steroids). The gas element is the principal heating source, with electricity as a booster although I believe the latest types have more powerful electric heating elements. However, this is only any use when you are on mains hook-up. If you intend to do a lot of free (or wild) camping, or use aires / sostas etc. you will, in the main, not have ready access to a mains supply.

'Wet' radiator heating (like a version of a home CH system) typified by the Alde system. This tends to be fitted to the more expensive motorhomes. Again, provision is made for both space and water heating. The advantage of the Alde system is that it is silent as it does not require a fan to push warm air around the van. Having said that, the Truma fan noise is not really intrusive, other than when it is first running at full-tilt to heat up a freezing van, but that soon settles back into gentle breeze.

Diesel-fired heating typified by the Eberspacher Hydronic system. This uses a combination of direct heating powered by diesel from the vehicle's main tank, and indirect heating via a heat-exchanger from the engine. It heats both water and space, and has the advantage of using the vehicle's 'waste' engine heat when on the move to heat water, which is stored in an insulated hot cylinder. When parked up, these units can be heard 'chattering away' under the van.

All three systems are 'current' and I am not aware of any tendency to phase one out in favour of another. I suggest you have a look at the web-sites of Truma, Alde and Eberspacher.

Philip

http://www.trumauk.com/
http://www.alde.co.uk/alde.php
http://www.eberspacher.com/


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## Grizzly (May 9, 2005)

Re blown air heating:

This can be delivered by two basic types of heater:

The combi boiler type fits in a locker and gives hot water and hot air but takes up quite a chunk of locker space with vents, pipes and so on. Truma have regulations about ventilation requirements for this so you'd have to have air circulation vents on the locker front or sides.

The "fire" type has a unit which looks like a gas or electirc fire ( not with visible elements) and this fits on a wall or on the front of a cupboard in the van. The water heater - smaller than the combi type- is then located in a locker.

You'd have to decide if you have locker space for the former or a free wall space and smaller locker space for the latter.

G


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## Wizzo (Dec 3, 2007)

If you are looking at older vans it may be a Carver system like mine. It consists of a gas fire with a "Fanmaster" unit sitting behind it. The gas fire can be used as a 'stand alone' unit like any domestic fire, the knob on the top acting as thermostat. It can also be used in conjunction with the fanmaster which delivers blown warm air heating, a more efficient way of warming the van quickly but if you are not on mains hook-up the fan unit can draw a fair amount out of the battery so we use it sparingly.

It will also work on mains electricity without gas, utilising electric elements in the fanmaster unit. These use either 1kw or 2kw depending on your setting. The thermostat for this is on the control panel.

Both gas and electric have either auto or slow settings on the fanmaster. The auto setting will set the fan going at full tilt until the desired temperature has been reached, the slow setting is constant (and pretty quiet).

I believe it will also run on both gas and electric at the same time if required but we have never felt the need for such extremes.

Our water heating is by a separate Carver boiler which is gas only but there are also gas/electric models.

JohnW


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## dovtrams (Aug 18, 2009)

russell

thanks for that comprehensive check sheet. this is like everything else in life, the first time is a bit traumatic in case you don't get it right!

dave


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