Blowing out water lines

[Manny]

It's been mentioned that instead of using antifreeze in the water lines they can be blown out with compressed air. I would like to try it this winter but am not sure of the process. Is a lot of air pressure needed? Does the air line have to be connected past the water pump, or is it okay to run the air through the pump? Is a special adapter needed? Any advice is appreciated.Thanks,Manny

 

[RichH]

Which water lines?

For your domestic water system no problem with blowing out the lines as there is no cast iron, etc. that would be affected. If however, you mean 'engine' then definitely NO, NOT EVER, DONT DO IT. Cast iron in a hot engine will develop ferrous oxide - the black (blue black) form of rust which is 'protective' against corrosion. If ferrous oxide is allowed to 'dry out' and is allowed to come in contact with humid 'air' will quickly change to RED rust (ferric oxide) which is destructive. Ferric / red rust will begin to separate the stratifications normal to cast iron castings .... and you will ultimately develop whats known as 'slab rust' ... huge platelets of rust as the cast iron begins to separate from itself inside the engine. Soooooooooo, for an engine made of cast iron, its best to leave it 'wet' and filled with antifreeze with rust inhibitor, then in spring RUN THE HELL out of the engine (to HOT temperature) to redeposit any ferrous rust that has changed (to red) during the lay-up. Engines that are 'blown out' with air simply wont last as long as engines that stored 'wet' (with antifreeze and rust inhibitor). 

 

[Manny]

Oops, not specific enough

I'm just referring to water lines to my faucets, etc.I'll use antifreeze on the engine.Manny

 

[Rich Stidger]

I use my dinghy air pump

High pressure is not needed- maybe 3-6psi.Drain all of your water tanks first.Then drain the hot water heater. I use a drill pump with a hose to the tank drain. No need to bypass the water heater if you blow out the lines.You can blow through the water pump but that will add a great deal of resistance. I disconnect the line from the water pump and adapt it to the air pump. It's handy to have some adapters that will connect to your water lines and some flex vinyl tubing to connect to your air pump.Open one valve at a time and pump air until the water just spits from the faucet.I also disconnect the line from the tank to the water pump and blow back into the tank(s) to clear the lines.Reconnect the lines to the water pump and you are done.

 

[seadaddler]

Easy with air

You can use a air compressor or the blower side of wet/dry vac.Turn on all water source until you get the tank pretty empty.I disconnect the line at the water tank use the wet/dry vac get the rest out.I have all hunter push pull connections and have easy connector to the airnd compressor that I made up,I blow out that line back to the pump and the pump.I disconnect the outlet side of the pump bypassing the pump a hookup my air hoseat this point and than start opening all water faucets one at a time until no more water just air comes out.Any more questions just ask,I have been using air to blow out all my boatsand rv's and lawn sprinklers for many years.I do use the pink rv antifreez for the yanmar ,AC,GEN and some drains.Nick

 

[sailingseadragon]

Use your dinghy pump

it will take about 15 minutes to blow all of the lines dry. These pumps move a fair volume of air at low pressure so you do not have to worry about damaging any fittings.See the following page on Sea Dragon's website for an example. My son and I blew the lines this weekend....http://www.sailingseadragon.com/winterize.htmWinter is near....Garner

 

[Bill C320 Papillon]

Pretty much like the other

posters have said. I use a small portable pump used to inflate tires. I disconnect the water lines on both sides of the pump to blow lines back to the tank and then blow the other side going to the faucets. I drain and disconnect the water heater then use a standard plumbing coupling to tie the cold water "in" hose to the hot water "out" hose thus bypassing the water heater.It seems like I would need a bigger compressor if i left the heater in place because of its large volume.The compressor came with several nozzles (for inflating basketballs and blowing up air mattresses etc). I use the one for air mattresses and wrap it with duct tape to make a tight fit inside the water lines.

 

[Manny]

Thank guys

I went down today and tried blowing out the lines. This was the first time I really had a good look at the "plumbing" on my boat, it is a miracle it even works. It took me a while to figure out what would work best and I eventually I was able to drain the hot water heater and pump air through the lines. Next year it should only take a quarter of the time I spent on it today.This saved me from having to buy about 8 gallons of antifreeze.Thanks again,Manny