What would be a good way to drain the water pipes in a house that would be left unoccupied for weeks at a time during the winter? It’s a pretty safe bet that in our case the plumber did not concern himself with this in that the house was built to be occupied continuously. Although I have not tried using an air compressor to blow the pipes out, I suspect that the 1-1/2 hp compressor that I have would probably not deliver enough air to do the job properly.
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just open up all of the valves inside and outside after you have shut the water off, then leave the valves open until it has drained, then go flush the toilets.
be sure to turn off the water heater, and by be sure i mean physically make sure it is off, don't just flip the breaker, test the wires/connection, or gas valve as the case may be.
if you are just trying to freeze proof you pipes opening the valves will work.
you might want to turn off interior valves just in case someone turns the water back on, and you might also want to leave the outside valves open a hair so the system doesn't build pressure with temp changes, although i doubt it would hurt anything once it has been drained.
i don't see any reason to remove all of the water unless you are trying to work on the system.
You really don't need a huge compressor unless you have a huge house. I've done them by making an adapter to go on a silcock and open one faucet at a time.
Don't forget to drain the water heater. If you can add a drain valvd to the hot side of the water heater with a shutoff to the tank you won't have to fill the tank with air.
I'm sure sombody might have an easier way but this worked for me.
Headstrong, I'll take on anyone!
Most houses will drain with the aid of a small compressor (PS, keep the pressure low, this is a low pressure-high volume application). For long periods, or really tough houses (e.g. with lots of low-hanging pipe), we've actually used potable trailer anti-freeze (I know people who just add some Vodka !).
Phill Giles
The Unionville Woodwright
Get something in all the p-traps so they don't freeze.
Beer was created so carpenters wouldn't rule the world.
I would only run 40-50 psi .
Thats good advice about the traps. I our trailer for the winter they make a RV antifreeze for the waterlines and the drains. We blow out the water lines and put the antifreeze in the drains.
Headstrong, I'll take on anyone!
1.5 hp compressor is what I use, and other than making sure it is on a 20 amp circuit (it will run continuously for long periods of time) it does great. Although I hook it up in the basement, rigging an adapter to a high point faucet would be smart.
Ensure all low points are drained. If you have any shower stalls, you need to figure out if they are plumbed from above. I've had to repair both sides of a shower valve in which the supplies came from above, trapping the water in the supply legs, blowing out the copper when they froze. All the air in the world didn't blow it out. I cut access holes in the wall behind the valves so I can drain them.
Put about 1/3-1/2 gallon of RV anti-freeze into the toilets after removing all water from the trap, and about 2-3 cups of antifreeze in all traps. (I use 1 gallon for a santard bathroom.) This is enough to displace the existing water. This should last for about 6 months.
Other drain points: Washing machine supply lines, dishwasher supply, refrigerator ice maker supply, instant hot water maker at the sink.
If you have HW basebaord heaters, don't forget to drain/purge them as well as the boiler.
If this is going to be an annual event, consider adding convenient drain and vent fittings with appropriate plugs.
Have Fun.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.