Question for "Blow Out the Water Line" gurus

Garyl53 wrote:
What is a recommended compressor tank size to be able to do a reasonable job of bowing out the lines at home? If not 3 gal. or 6 gal. then what? Is there a way to use the FW tank as an expanded pressure tank and then run pump and open valves one at a time? Assume you would need to seal off the FW fill vent tube but are there any other vents to a FW tank?

You don't "need" a huge compressor but higher CFM compressors tend to make the job much faster.

For many years I used a small 2 gallon "pancake" compressor with good results.. Now days I have a higher CFM compressor in my garage which works just as well..

Lower CFM compressor just means it takes a bit longer to build up pressure and you wait a bit longer..

I set my regulator to zero then hook up.

Pull the drain plug on the hot water tank, allow to empty then put plug back in.

Close all faucets.

Adjust pressure up to 30 lbs..

Wait for system to build pressure.

Go to faucet nearest the water inlet.

Open that faucet (cold first) and allow water to come out, leave open until a mist comes out then close (repeat for hot water side). Open and close a few times until only a light or no vapor comes out.

Go to the next faucet and repeat.

Don't forget to run the toilet to clear the line..

Set regulator back to zero and open faucets to allow pressure to bleed off.

Open low drain points.

I also loosen the hot water tank drain plug and open all faucets kind of a "belt and suspenders" type of thing which helps keep any pressure from building up..