Wintering the Van

Wintering the motorhome was high on the agenda last weekend before the current cold snap.

Given it's almost impossible to determine whether there's any water left in a motorhome's plumbing, I thought about alternatives to simply draining down. These were the ideas I came up with.

• Filling the system with propylene glycol - the same stuff I use in my vape, which is food grade. It has a freezing point of -59 degrees C and can be easily flushed out after the cold weather as it's miscible with water.
• Filling the system with alcohol - that would be handy after winter as a bar. Whisky's freezing point is -17 C, but that would be a bit expensive.
• Attaching a barrel of beer - but beer is low alcohol and freezes at only -2 C. However, again a good idea for summer, with the addition of a cooler unit.

The propylene glycol (not ethylene glycol, which is poisonous) idea was best, but I would need about 10-20 litres of the stuff (the water heater alone takes 9 litres) and I was up against the clock. Also I had to replace the water pump, as it had managed to blow itself up. Filling the system with PG would additionally require me to extend the hose on the pump in the water tank, so I could pull the pump out of the tank in order to place the pump in a container of PG to flood the system. It's definitely an idea I will use next year.

It's not the cheapest solution, as PG costs about £30 for a 5L container, so I'd first need to determine the exact capacity of the plumbing system. However, I can mix the PG with water, which will make it go further, raising its freezing point. Apparently a 25% PG concentration will increase the freezing point from -59 to -10, so a little will go a long way. I can also recycle it for use in subsequent years by using an air pump to force it out after the cold weather. Putting some dye in the PG might be a good idea too. More work is required on this solution. - primarily determining the plumbing system's exact capacity, but I can't see it being much more than 20L.

I decided in the end to simply drain the system down, emptying the last of the water in the tank with a hand operated bilge pump and hope for the best.