MIRO and on board tank

[Buckman]

I am aware that the MIRO of a caravan includes everything in it as it comes from the factory which includes the waste master if the unit has an onboard tank. In the Buccaneer owners handbook it states that the MIRO is the weight as the caravan leaves the factory plus 10kg per gas bottle as per the number of connections on the regulator.
In addition, it includes 20kg of gas, EHU cable and should include fresh water if the caravan has an onboard tank. The EU directive refers to 90% fresh water in the onboard tank, but surely the hot water boiler can be regarded as an on board tank?
However a bone of contention is the amount of fresh water you can carry water if for instance you have a 40 litre on board tank. Can you carry the tank 90% full (36litres) and is it included in the MIRO as per the NCC? In the Elddis Buccaneer Owners Handbook it specifically states that the MIRO is calculated with no water on board or in effect it is also excluding the water in the heating system.
Seems to be a conflict here between the NCC and Elddis statements?

 

[Raywood]

I could not find a definition of MIRO on the NCC website so cannot be sure what it says nor was I aware of any relevant EU directive. The definition does seem to vary a bit between manufacturers but I am not aware of any of them including water in it.
If the makers handbook says on their caravans it does not include water that is the one you should go by.
I would not try carrying a tank 90% full even if you can gauge this. Water in a tank on the move will create waves, which in theory can create instability, although we have traveled with a full tank on many occasions without problems but a part full one would be more likely to cause problems.

 

[otherclive]

For mine I contacted Swift who gave me a precise breakdown which even included for the weight of documents included with the Caravan. However I only recognise an empty van ready to roll with gas and battery and mover. Which I then took to the weighbridge to give me my starting point for actual payload.

 

[Buckman]

I could not find a definition of MIRO on the NCC website so cannot be sure what it says nor was I aware of any relevant EU directive. The definition does seem to vary a bit between manufacturers but I am not aware of any of them including water in it.
If the makers handbook says on their caravans it does not include water that is the one you should go by.
I would not try carrying a tank 90% full even if you can gauge this. Water in a tank on the move will create waves, which in theory can create instability, although we have traveled with a full tank on many occasions without problems but a part full one would be more likely to cause problems.

If the 36kg is included in the MIRO and you do not fill the tank, in theory this should give you an extra 36kg of payload which could be very handy? This is the main reason why I am asking the question.

 

[Damian]

If you have the Alde heating system then the fluid in that will have been taken into account in the MIRO as it is unreasonable to drain the mix and refill each time.

The 40ltr fresh water tank will be considered empty as it is ridiculous to even think of travelling with that amount of water, in an unbaffled tank , sloshing around.

Allowance is made for a small amount of water in the toilet flush , but Thetford and Dometic do not recommend having any more than about half full to stop any overspill when travelling.