# Truma combi, back to basics for us newbies, Please



## mandyandandy (Oct 1, 2006)

Ok. We have been on a visit to our van, due Feb 10th. It has a Truma combi heater, this is going to sound comical to some but here goes.
1. Does the large tank under our sink (black) hold the heater and does that hold water.

2. Do we heat the water as we need it or keep it at a constant temperature somehow.

3. When it says combi this means what, we can run it off gas we realise, but is it the leisure battery or just when on hook up.

4. If you have to heat the tank each time from cold how long does it take?

5. It is a Truma 4kw comi heater. Blown Air heating. Truma water heater 500

Hope this doesn't leave you as confused as us, we have tried to see from other threads but everyone seems to know what they are talking about so nothing really basic in there. 

Many thanks
Mandy


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## JockandRita (Jun 1, 2005)

Hi Mandy,

Q 1 = yes, it is the heater and holds the water (Combi boiler)

Q 2 = we leave the hot water on all the time when we are using the van in winter. In the summer, however, we use as needed. Ours is a gas only system.

Q 3 = Combi means that it is a combination water/heating appliance, with the recent models having a 240 volt facility.

Q 4 = It takes about 30 minutes to heat the water to washing temperatures. Central heating however, is instant.

When we contacted Truma to enquire about fitting the mains heating belt, we were informed that they were inefficient, ie, water temp of 40 degrees, and that we could buy an awful lot of gas for the price it would have cost us for parts and labour.

The newer models have the mains heater built in.

Hope this helps.

Jock.


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## peejay (May 10, 2005)

Hi Mandy;

q1. If its a combi boiler then yes.

q2. you can leave it on all the time whilst on site no probs, i'm not sure if this is more economical but thats how we use them. You can also use it on demand but you will need to wait probably about 20 mins until the tank has heated.

q3. Combi means its a combination of water and room heater. Gas is the main power along with 12volt battery power to run the blown air fan. Some also have 240volt mains option as well, this will be annotated on the heater with 'EH' or 'EL' on the end of the C**** model number.

q4. About 20 - 40 minutes depending on the model and possibly more when you are also running the room heater as well.

q5. Check the label or handbook, it might be either a 'C3402' or a 'C4000' or possibly a C6002'. Also, If there is 'EH' at the end then it has the mains 240v option fitted.

C3402 - http://www.truma.com/truma05/en/products/detail2_en_84071.html

C4000 - http://www.truma.com/truma05/en/products/detail2_en_84311.html

C6002 - http://www.truma.com/truma05/en/products/detail2_en_84191.html

pete


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## peejay (May 10, 2005)

Sorry Jock, you must type faster than me. :wink: 

pete


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## JockandRita (Jun 1, 2005)

peejay said:


> Sorry Jock, you must type faster than me. :wink:
> 
> pete


No problems Pete, at least we are both singing off the same hymn sheet. :lol: :lol: :lol:

Jock.


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## Grizzly (May 9, 2005)

mandyandandy said:


> 3. When it says combi this means what, we can run it off gas we realise, but is it the leisure battery or just when on hook up.
> Mandy


Only on gas or hook up Mandy. You'll run your 12v leisure battery down in seconds if you try a 4kw heater from it.

You have to be aware of the current you can draw at different campsites - ie the number of amps ( 4, 10. 16 and so on) You then have to adjust the number of appliances you have on to suit. This might mean that you can't run a room heater, hot water, kettle and so on all at once.

There are tables setting out the current drawn by most appliances and you then have to work it out accordingly. If you get it wrong you trip the fuses at best and either have to go outside to sort it out or go to the office to get them to do it ! Doesn't make you popular with fellow campers on the same supply !

G


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## 101368 (Oct 12, 2006)

Grizzly said:


> mandyandandy said:
> 
> 
> > 3. When it says combi this means what, we can run it off gas we realise, but is it the leisure battery or just when on hook up.
> ...


Best sites have a nice water proof cover over a trip switch. But no site should be powering more than one unit from the same trip. Tripping the whole site should be nearly impossible.


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## Grizzly (May 9, 2005)

emgee said:


> Best sites have a nice water proof cover over a trip switch. But no site should be powering more than one unit from the same trip. Tripping the whole site should be nearly impossible.


Not the whole campsite...the 3 or 4 vans on the same bollard or whatever you call it.

G


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## peejay (May 10, 2005)

Grizzly said:


> mandyandandy said:
> 
> 
> > 3. When it says combi this means what, we can run it off gas we realise, but is it the leisure battery or just when on hook up.
> ...


If I interpret you reply correctly Grizz then thats not quite correct. If you run a combi boiler on gas without hook up then its only the fan that consumes 12v from the leisure battery, you can operate without mains in this mode for quite a while depending on how powerful a battery (ies) you have fitted.

pete


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## Grizzly (May 9, 2005)

peejay said:


> If I interpret you reply correctly Grizz then thats not quite correct. If you run a combi boiler on gas without hook up then its only the fan that consumes 12v from the leisure battery, you can operate without mains in this mode for quite a while depending on how powerful a battery (ies) you have fitted.
> pete


Hi Pete
I think I'm mis-reading the original. I thought Mandy was expecting to run her heater on either gas, mains *or 12v *and pointed out that you could not do it on 12v - meaning alone, without gas or mains. Presumably the fan can be run alone to distribute cool air in hot weather but it doesn't heat unless either the gas is on or the van is on mains.
I'll shut up and go back to rummaging around in the private lives of my distant rellies. I do know a bit about that....!

G


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## 101368 (Oct 12, 2006)

Grizzly said:


> emgee said:
> 
> 
> > Best sites have a nice water proof cover over a trip switch. But no site should be powering more than one unit from the same trip. Tripping the whole site should be nearly impossible.
> ...


Still bad practice.


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## Grizzly (May 9, 2005)

[quote="emgee
Still bad practice.[/quote]

That may be true but it is usual on CC and C&CC sites.

G


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## peejay (May 10, 2005)

Hey Grizz;

No problemo, been there done that myself many times :roll: , your post still highlights the need to observe the amount of amps being consumed on a site before tripping the supply, especially if using a truma on mains if its fitted, so your words weren't wasted.

Pete


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## 101368 (Oct 12, 2006)

Grizzly said:


> [quote="emgee
> Still bad practice.


That may be true but it is usual on CC and C&CC sites.

G[/quote]

I don't do that many of them but all the ones I've been to have had the supply correctly wired and a full sixteen amps available. Sharing means you either restrict everyone on that trip to 16 amps max shared between them or you run a severe fire risk in case of a fault.


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## Grizzly (May 9, 2005)

This, from the Practical Motorhome sitemakes it clear:

_Amperes - or amps - refer to the quantity of electrical current flowing along an electrical cable. The pressure that pushes it along the cable is measured in volts. Multiplying the volts by the amps gives the amount of energy an appliance uses, expressed in watts (W).
In the UK, normal mains voltage is 230V, though it can vary slightly. The highest amperage of an electrical appliance is 13A, so based on the formula, this becomes 230 x 13, which equals 2990 watts. 
The maximum amps available from the hook-up on a UK site is 16A; often it's less - 10A or 6A. Also, although a nominal 16A may be available, it is unlikely that this amount will reach your motorhome if other users are also drawing current. 
Hooking up, you need to calculate the total amperage you can draw without tripping out the mains. Add up the wattage of all the appliances and then divide it by 230. Thus a 2kW heater, 125W fridge, 750W kettle, 50W TV, plus two 40W lightbulbs, totals 3005 watts, which, when divided by 230 gives you 13 amps. So if the site's supply is less than 16A, switch some items off to avoid tripping out the mains. _

G


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## mandyandandy (Oct 1, 2006)

Thank you all you good people, you have answered the questions with great expertise as I expected of course!!!

We did wonder about running it soley off a 12V so it was relevent.

Is a bit of a gas guzzler if you keep it on full time, not that we would that often as we plan to be on the move more often than not. 

Thanks again, you are great !


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## 101368 (Oct 12, 2006)

Grizzly said:


> This, from the Practical Motorhome sitemakes it clear:
> 
> _Amperes - or amps - refer to the quantity of electrical current flowing along an electrical cable. The pressure that pushes it along the cable is measured in volts. Multiplying the volts by the amps gives the amount of energy an appliance uses, expressed in watts (W).
> In the UK, normal mains voltage is 230V, though it can vary slightly. The highest amperage of an electrical appliance is 13A, so based on the formula, this becomes 230 x 13, which equals 2990 watts.
> ...


Whilst it gets the general idea right. It's riddled with minor errors. Can you name a site that is wired the way you describe. If only so I can avoid it


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## Rapide561 (Oct 1, 2005)

*Gas usage*

Hi

I have a Truma thing that runs off gas and electric. The gas is the most powerful but for general use, I run at 1800w electric which gives red hot water and a warm van.

However, I do not think it is that thirsty on gas usage.

From 5th December 06 to January 1st 07, I only used 8 litres of LPG. This covered using the oven probably 5 days per week for at least one hour, the hob and the boiler.

I ran the boiler on gas in December when it was really cold.

The Swift manual states on gas operation, the boiler in my van - capable of 6000 watts worth of power wil use between 170 and 490 grams of gas per hour. Now, remember that to get a freezing cold van warm, to hot, will use a lot. Once the van is warm etc, the thermostat kicks in and controls the power requiremment.

The site I am on at present charges me a mnimal fee to be here, plus electric on the meter. I am paying about £2.50 per day for electric which would be about 6 litres worth of gas. I might switch to gas heating for a week and report back.

Russell


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