Truma trauma C6002 Combi

[Gerry]

When the space heating is up full we get absolutely no hot water, as if the fan is blowing all the available heat into the habition area, leaving none to heat the water.

When the space heater is running at its lowest point; not space heating, the water then begins heating up.

Anyone have this traumatic problem??

:-S

[fred grant]

have a look at the instruction booklet gerry, it explains why this happens. you really need to use gas also in cold weather.

 

freezing fred

[Derek Uzzell]

Gerry:

 

This isn't a problem as such - it's just how Truma C-Series heaters behave.

 

Your C6002 has gas-burners in the centre that heat a heat-exchanger. Surrounding the heat-exchanger (BUT NOT TOUCHING IT) is a 12 litres capacity water-jacket.

 

When the appliance is in water-only heating mode, a 2kW output gas-burner heats up the heat-exchanger that, in turn, transfers that heat across the air gap between the exchanger and the jacket containing the water. This process is quite efficient and permits the water to be raised from 15C to 60C in around 30 minutes.

 

When the appliance is switched to space-heating mode, air is blown down through the air gap between the central heat-exchanger and the water-jacket and out through vents in the lower part of the heater. While this is happening, most of the heat-exchanger's output is being transferred to the air continuously passing over it and only a limited amount of heat crosses to the water-jacket.

 

Even though a C6002's gas burners can provide a 6kW output during 'full bore' blown-air operation, this is linked to a high fan speed. Even though the burners are blasting lots of heat into the heat-exchanger, there's also lots of air passing over the exchanger to extract that heat before it is able to reach the water-jacket. Because of this Truma quote 80 minutes (approx) to heat the water from 15C to 60C while the appliance is operating in 'air-heater + boiler' mode.

 

More recent C-Series appliances have a control switch that allows selection of "Winter operation (heating WITH hot water requirement)" or "Winter operation (heating WITHOUT hot water requirement)".

 

In the former case the appliance continues to run the 2kW gas-burner (but not the blown-air fan) during those intervals when the air within the motorhome has reached the pre-selected temperature and 'air heating' has temporarily shut down. So water heating will take place until (eventually) 60C is attained.

 

In the latter case, when the air within the motorhome has reached the pre-selected temperature, the appliance shuts down totally. Some water heating will occur, but the temperature attained will be unpredictable. (This feature permits gas savings to be made if you don't need hot water and, obviously, there would be little point in the appliance entering water-heating mode if the heater had been drained down.)

[michele]

Silly yes laugh but you don't get to know without asking so please excuse me.

 

If there is no water in the system can the boiler blow up ?

how much damage would you cause would it now be a new boiler .

 

I ask because I did turn it on not knowing there was no water It did not seem to of had any advers effects hubby went mad .

I did not know we had no water also I did not know that the boiler did not hold its own water so this could never happen..

 

If its to silly dont answer just trying to understand .

[sshortcircuit]

Will operate without water with no problems. Its in the book and I have operated it without water

[Brian Kirby]

michele - 2007-07-22 12:23 PM Silly yes laugh but you don't get to know without asking so please excuse me. If there is no water in the system can the boiler blow up ? how much damage would you cause would it now be a new boiler . I ask because I did turn it on not knowing there was no water It did not seem to of had any advers effects hubby went mad . I did not know we had no water also I did not know that the boiler did not hold its own water so this could never happen.. If its to silly dont answer just trying to understand .

Assuming you're talking about a Combi heater, Michele, the answer, really is RTM!  In the blessed manual, that fount of all wisdom, you will find user guidance, among which should be words to the effect that it is OK to use the heater without water content.  However, for best effect, the control should be set to "space heating"!  Nevertheless, don't take my word for it, read the manual for your heater - you never know when the instructions may change. 

However, notwithstanding all that, mine says:

"Heating operation is basically possible without restriction with or without water content."

Seems clear enough, so no "domestics" should result!  :-)

[michele]

So I have no worries then ?. I can understand that if I drained the central heating system at home it would all drain and that there would be no water in the boiler not to turn it on.

 

I did not realise that if you let the water out of the M/H in winter for freezing that it would actually drain the boiler silly really what did I expect .

 

 

cheers.

[Vernon B]

michele - 2007-07-22 12:53 PM

 

So I have no worries then ?. I can understand that if I drained the central heating system at home it would all drain and that there would be no water in the boiler not to turn it on.

 

I did not realise that if you let the water out of the M/H in winter for freezing that it would actually drain the boiler silly really what did I expect .

 

 

cheers.

 

Which goes to show what a good bit of kit these units are michele.

 

On a seperate but related matter I think I also read in that comprehensive manual that it's a requirement in Germany for the boiler to have a service or something replaced after 10 years. Has anyone owned one of these units that length of time and done anything about that recommendation?

 

Vernon

[Derek Uzzell]

Vernon:

 

I remember reading somewhere that Truma convinced the German technical safety authorities that (for Truma heaters) 10 years was an unnecessarily short interval between compulsory heat-exchanger replacement. Nowadays the Truma Operating Instructions leaflet specifies a 30 year interval. I've no idea if this revised interval applies retrospectively to Truma heaters and (as you rightly say) the rule only applies to motorhomes registered in Germany.

[wints]

I've got the C6002 in my Mirage 6000 and i've got a problem with it. There is a constant drip from the frost safety valve, enough to de-pressurise the water system which then triggers the pump every 3 or 4 hours. I suspect that there will be a replaceable o-ring seal in this valve but does anyone know for sure ?

I always switch the pump off at night and when we go out.

regards

Allen

[Derek Uzzell]

It needs emphasising that only 'Second Generation' Truma C-Series (Combi) combination heaters can be safely used with no water in them. These are models C3402, C4002 and C6002, plus EL variants (C3402EL, etc.) and the C6002EH.

 

Truma introduced Second Generation Combis in the mid-1990s (I don't know exactly when) to replace their C3400 and C6000 appliances that had a significantly different design. If your motorhome is fitted with the earlier model Combi you should NOT operate it empty of water. Running a C3400/C6000 'dry' risks cracking the water-jacket's vitreous-enamel inner lining. Rust will then attack the water-jacket itself and water leaks will result. Truma(UK) told me that leaking C3400 or C6000 Combis are effectively beyond repair.

 

(If your leisure vehicle's water heating is via a 'traditional' Truma Ultrastore B10 or B14 boiler, then you should ALWAYS ensure this has been filled with water before operating it. Obvious really, but I guess it's still worth saying!)

 

Allen:

 

Can't really advise on your anti-frost drain-valve inquiry. I suspect that, as the complete valve is FAIRLY inexpensive, there will be no 'official' repair parts available for it and, if there are problems, Truma would expect the valve to be replaced in its entirety. The Truma(UK) technical chaps should know. (I think their current e-mail address is technical@trumauk.com and phone number is 01283 586020. I was going to refer you to the website www.trumauk.com but I notice that it's (obscenely) hacked at present.)

 

It's possible that the minor leak is due to water-scale build-up on the valve's internal sealing surfaces (as you suggest, quite possibly an O-ring), so you could try removing the valve and running a strong citric acid solution through it to try to dissolve such residues. This might obviate the need to dismantle the valve (assuming it can be dismantled, of course!). This ploy is certainly effective when applied to leaking seals on Thetford toilet cassettes.

 

If your valve can't be repaired, you might choose to replace it with a manual safety/drain valve (about £20 in the Truma catalogue) that draws no 12V power and won't open inadvertently if the leisure battery goes flat. (But, of course, a manual valve won't provide any automatic frost protection.) Next Generation 'horizontal' Combis will, apparently, have a non-electrical anti-frost drain-valve that performs the same functions as the present electrically operated valve but without the 12V drawbacks.