Ok client needs inspection and it has been recommended to him that he has a air pressure test done on his water pipes instead of having the water turned on. We have lots of snow on the ground here and temps are below freezing.
Q: If I was buying and the heater is operable I personally would turn the unit on let it auto run for a day or two to warm the house up then I would turn the water on from the main so I could run a complete test.
Who disagrees? If so why would you run a air pressure test?
How are you going to test for drainage leaks and blockages with air?
The buyer or seller should have the house de-winterized and you do your normal inspection. Then someone needs to winterize again, just not you or you can be liable.
Recommended presure test (instead of having the water turned on) by whom? That answer may go a long way to knowing why it was recommended.
The air pressure test would be to see if the water pipes are intact, instead of seeing the water come out of the water lines when it is turned on.
If they want to do that, prior to turning on the water, fine, probably prudent.
If the water is not on for the inspection you cannot do a complete plumbing inspection (obsevation, in Illinois ;)) no matter the results of the pressure test.
In my neck of the woods, pressure test is common on new construction, but not mandatory. It is a smart cover your butt move, making sure a pipe inst burst between floors. In other words, they would rather find a leak with air, rather than water.
I might steal this idea 
I guess you can check the supply lines with air, but it’s still an incomplete test. How do you know if hot is hot and cold is cold? How do you check the drains?
I agree, if they want to make a sale they should turn on the heat.
John Kogel
www.allsafehome.ca
Get them to turn the heat and water on . Save your butt
You better have some help monitering the lines when you turn it on. If the damage is already done running the heat for a week isn’t going to help.
Air test
Air tests are applied by closing openings and pumping air into the system until a uniform pressure of five pounds registers on a gauge. The system is kept at the same pressure for time and then tested again. Any drop in the pressure indicates a leak in the system. The air test has two principal advantages.
It can be made in freezing weather, and it subjects the entire system to a uniform pressure. On the other hand, it does not indicate location of the leak. Consequently, unless the leak is a big one, it may be difficult to find. A soapy lather applied to all joints with a brush will reveal leaks by forming bubbles wherever air is escaping.
Unless you are planning on being the one to do all of this and know how to do it, have the necessary equipment to do it. Well, you know the rest. Typically, we would put pressure on the system and come back the next day to check the gauge to see if it had dropped. This was all done before any drywall was put up and all the pipes are exposed so you can check the joints and couplings.
Sounds like the old “ten foot head” test, but that is a wet test. As Doug mentioned, the dry test is uniform pressure of 5psi. The time is at least 15 minutes. But as mentioned, this is a pre drywall/fixture test. Just ask yourself how you’re going to seal off the drains? And I’m not sure tape or something of that nature will hold off 5 pounds of pressure. You may just be finding a leak in the tape job. Might be a lost cause. You can’t do the smoke test either, because joint are concealed.