Winterising pressurised fresh water system

I now take the approach that it is better to keep the boat above freezing with heater on board all the time. The cost is not high compared to the cost fixing bits and pieces that have frozen.

Guess it depends on your situation. We stay in during the winter but it's in fresh water up a river locked from the sea. River can and on occasions does freeze and can't leave a heater on as electricity is on a timer system. So, belt & braces, I drain the entire system.
 
See the photos at the very bottom of this page http://coxengineering.sharepoint.com/Pages/Calorifier.aspx Calorifiers cannot be emptied in the slightest by continuing to operate the pump with the hot tap open. Once the tank is empty the pump will be pumping air, which simply bubbles up through the water in the calorifier. Indeed, in some installations the water in the calorifier can run back when the pump is switched off, causing fractures to upstream plastic fittings such as elbows and tees if they freeze.
 
I've not had any problems in East Anglia by just draining whatever comes out with the taps. What I do, though, is to drain the water pump itself (by simply unclipping one hose) since there are many tales of pumps failing after a freeze.
 
See the photos at the very bottom of this page http://coxengineering.sharepoint.com/Pages/Calorifier.aspx Calorifiers cannot be emptied in the slightest by continuing to operate the pump with the hot tap open. Once the tank is empty the pump will be pumping air, which simply bubbles up through the water in the calorifier. Indeed, in some installations the water in the calorifier can run back when the pump is switched off, causing fractures to upstream plastic fittings such as elbows and tees if they freeze.

Which is why after draining the calorifier I blow through the pipes with a compressor, in order to leave as little water in any low points as possible. This always displaces quite an amount of water that was left behind when the pump stopped pushing out the water. I also do this with the pump, which I suspect is the most vulnerable part as it has no room for any ice to expand, so will crack.
 
My friends in Maine, where it gets seriously cold, drain the tanks then pump food grade anti freeze, which is a lurid red colour, until it appears at all the outlets. Job done.
 
Thanks for all the discussion - clearly lots of different ways of skinning the winterising cat! I have a heater on board that is running in frost mode to stave off any mould, so I will just empty the tanks, then drain down the calorifier for now. If I were leaving it with no heating I would go for the food grade antifreeze me thinks.
 
Eeeee I claim a lakesailor on the last post.:D

#26 :-food grade anti freeze
#4 my post :-antifreeze treatment for fresh/drinking water systems
 
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I havn't drained the water systems on my boat for years now.

Instead I empty the tanks to about 1/10 their volume. I then add a small packet of salt approx. 500g, then open all the taps sending the salt around the system until I can taste salt at every outlet.... taps, shower, on both hot and cold systems.

Most pumps are able to be used with salt water and as long as I don't heat up the calorifier I see no harm done.

At the beginning of the season I empty all systems from every outlet, fill to about 1/4 and drain out x 2. or until there is no taste of salt.

Simples!

S.
 
I havn't drained the water systems on my boat for years now.

Instead I empty the tanks to about 1/10 their volume. I then add a small packet of salt approx. 500g, then open all the taps sending the salt around the system until I can taste salt at every outlet.... taps, shower, on both hot and cold systems.

Most pumps are able to be used with salt water and as long as I don't heat up the calorifier I see no harm done.

At the beginning of the season I empty all systems from every outlet, fill to about 1/4 and drain out x 2. or until there is no taste of salt.

Simples!

S.

What temperature do you think that protects it to?

My boat winters ashore, and the yard is a bit of a "frost hollow". I empty all the parts which have a small volume, i.e. pipework, pump etc, but leave tanks half full, and calorifier full, with a tube heater on a thermostat, down beside the engine.
 
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