Tank Blankets

Heebson wrote:...

Did you ever trace the heat blanket wires back from underneath into the van? ..

No - only as far as the connectors for the Tank Blankets

The Bargee wrote:I wonder if there is anybody here who can state confidently that the Tankblankets are worth having, and that they would be happy to rely on them in a serious freeze-up?

My tank blanket for the fresh water tank remains to be re-connected after removal of the EC700. I have been planning to wire it through a simple switch with a bright LED warning light, but I haven’t got round to it yet, partly since I am not convinced it will offer sufficient help to be worth connecting.

We have no intention of going to seriously cold areas but if we did, or when we get another serious U.K. cold snap, then we would drain down and use 5 litre water carriers. We lived on traditional narrowboats for some time last century, where the only water supply was from a couple of 3 gallon Buckby cans on the roof, one of which we brought into the cabin at night and stood in front of the coal range to stop it freezing. 

More recently I was living on a remote site in my caravan whilst working away during the Beast from the East in March 2018, which was horrible but I was happy so long as I could warm up after work and keep some water unfrozen in the caravan overnight. The caravan was of course fully drained down. 

I would do the same again now if we were caught out in a serious freeze. Fill some cans from a tap (if I could find one that wasn’t frozen) or buy mineral water from Aldi, and drain the van down thoroughly. Otherwise in a severe frost I would worry about the pipework freezing in areas such as behind the shower, where heated cabin air may not penetrate, which is to my mind a valid concern, certainly in PVC’s if there are shortcomings in the insulation.

I wouldn't bother with the waste water tank heater unless you are prepared to fit PipeBlanket:

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For the freshwater tank heater I would disconnect it's spade connectors from Sargent's harness and give it a temporary 12V supply to measure how much current is flowing.  This will confirm it's working and allow a comparison with my original and replacement heaters.  It will also show its wattage which I am sure will be less than shown on its label.

Before I discovered my original heaters only worked when both tanks were >25%, I had only used them in anger on a couple of occasions.  I think my waste water tank would have been >25% so I think they would have both been working.  I didn't encounter any problems but nor do I know for certain I would have done if the heaters had not been working.  Nor do we know whether Heeb's problem was caused by his freshwater tank heater not working.  His extreme low temp (-8°C) may have been a coincidence.

Like you, we don't plan on going to seriously cold areas.  The risk for us is a prolonged cold snap in this Country for which there are various options:

1. Use water containers inside the van.  We have done so on two occasions in our current van when the water pump failed. On one we managed because the site had a facilities block but on the other where there was no facilities block it was very difficult but fortunately we were at the end of our trip.  There was a third occasion when the EC700 caused a fault on the Truma which prevented it from heating the water (and the van).  This was nearly as bad as the water pump failing as we couldn't shower and there was also no facilities block. Again we were lucky it was towards the end of our trip. Our experience from all this is that whilst we must always have an internal water container with us, having to use it for all our freshwater supply is a poor option. 
   
2. Hope the water doesn't freeze.  The question then is how cold does it have to be and for how long before freezing interrupts the van's freshwater supply?  I have no data or experience to back it up but an overnight temp of say -3°C or below with the shaded ground beneath the van remaining frozen during daylight hours are reasons for me to be concerned.
   
3. Cancel our trip.  Clearly there are occasions when this has to happen but IMO cold shouldn't be one of them. 
   

The TankBlanket heaters are not designed to stop the whole tank from freezing and won't stop its drain tap from freezing.  But if positioned correctly, it should stop the freshwater from freezing around the submersible pump or outlet pipe if a Shurflo has been fitted.  I am as confident as I can be that the two replacement heaters I have fitted to my freshwater tank, sandwiched under a closed cell foam camping mat, will keep my water supply going in the coldest of conditions in this Country.  I wasn't able to put it to the test last winter as, unlike previous winters, it wasn't freezing during our trips.  The nearest we came to use it, it was -7°C in the van whilst packing it at home in the early morning but by the time we reached our site the temp had risen considerably and didn't drop again.  Had our trip been a few days earlier I would definitely have used the tank heaters.