cold weather

I have recently bought a Nuevo. The dealer told me that it would not be necessary to drain the flushing tank because the pink additive contains antifreeze. Is this advisable? I live near London and we don;t usually get very extreme winter weather.

I have never seen anything on a bottle of pink additive to say that. It would also depend on what brand of pink so I would ignore that comment. I always drain whatever is left in the flushing tank by simply flushing it through as the Nuevo doesn't have a drain tube (well at least I've never found another way of doing it).

Hi Jeff
My last van was a 09 Nuevo and I used to drain it down every winter, if your van is the X250/333 model you should have a wee drain plug  inside the exterior cassette door,it is located above the WC cassette itself.
Remove this plug with a cup underneath to catch the dregs of pink flushing fluid,  once you have drained the flushing tank.
I have drained down my 08 Sigma a few weeks back .
Boaby

Hi there,

The concentrated bio laundry liquid that we use (Formil from Lidl) has certain anti-freeze qualities so I don't bother dismantling anything when I drain the flush tank.

I haven't bothered measuring the level at which the mixture will freeze but it has a "eutectic" point that is below the zero degrees of pure water.

A "eutectic" is the point at which a mixture will freeze (i.e. go solid).  As an example, and from memory, mono-ethylene glycol (MEG) freezes at -10 degrees and water freezes at 0 degrees.  However, a mixture of 55% water and 45% MEG will not freeze until the mixture reaches -40 degrees.

What happens with a mixture of say 85/15 is that, as the temperature falls below zero degrees, the water crystallises (i.e. freezes) to form a "slush" and the concentration of MEG in the remaining mixture increases; this continues as the temperature continues to drop until it reaches the 55/45 point after which it will remain as a slush until it reaches the eutectic of the mixture and everything goes solid.

Put simply, even a small amount of MEG mixed with water will give some protection in that the liquid mixture will turn to a slush rather than the expanding solid that causes damage when water freezes.

So, rather than drain everything down, what I do is to increase the concentration of bio-liquid the fill before I intend to drain everything down and then keep touching the pump switch to make sure that there is very little liquid resting in and around the pump when I lay her up for the winter.

Hope this helps. 

Best regards,

Ian's very detailed reply reminded me a phenomena which was reported by motorists during the cold winter of a few years ago. Having left drinking water bottles in the car overnight they were surprised to see the water still liquid the next morning even though the temperature was well below freezing. As soon as the liquid was shaken it quickly turned to ice. Up to that point the water molecules had no 'seed' crystal to start the solidification process.

This process of 'supercooling' (see wiki etc. ) will not occur anywhere in water systems of a motor-home.

On my  Nuevo the flushing tank rubber bung is very fiddly to get out as the water then splashes. I thought I'd be clever this winter and use a funnel, this soon filled up and then overflowed back into the flush tank compartment and then over me. The bung had been washed into the funnel and blocked it!

Regards
Fred

Hi there,

  but ....

One of the specification tests for benzene is the freezing point.

A small flask filled with benzene is sunk into ice which has been seeded with salt to make it melt at a temperature below zero celsius.

The benzene is stirred and the temperature drops to well below the freezing point (+5.53 degrees celsius).

It's weird to observe when all of a sudden the benzene seems to realise that it should be a solid and promptly freezes to a solid within a second; and the temperature then rises to +5.53 degrees (if it is pure benzene) before starting to fall again.

Another useless piece of information cluttering up my brain! 

Best regards,