Kitchen Gas Appliances - How to flush propane lines?

My wife is chemically sensitive (CFS + MCS). We are thinking about buying a house out in the country. The problem is, within five minutes of walking in a certain prospective house, she gets really dizzy and can't think straight. We think this is due to a small propane leak (not enough that I can smell it, but she has become extremely sensitive to chemicals, even if they are not strong enough to smell), and we are planning on going all-electric (fumes from natural gas etc. are not good for her either). So what we need to do is, flush the lines and see if she still reacts to the house -- if not, we put in an offer and convert the house to electric. Other than this, the house is perfect, and we've been looking for months, so we'd like to perform this experiment and then move forward.

So how does one go about flushing propane lines? Is it as simple as shutting off the valve at the tank, and burning the range until the flame goes out? I realize that once the pressure is removed, there will still be some amount of propane in the pipes - how can one flush that out as well? Is this something I should ask a professional to do, and if so, how much would it cost?

The house has propane range/oven, heaters, and water heater. So we're probably talking an additional $10K to convert all of that.

Also, does anyone know if propane is absorbed into the walls etc., to slowly outgas over time (i.e., removing the propane service will not necessarily help my wife if enough propane has slowly built up in the walls, floor, ceiling to keep her exposed for months to come)? Or is it volatile enough that it should all escape through the walls and insulation within a few days, especially if we open the windows?

Thanks.

Hello bgrayson. Welcome to my Gas Appliances topic and the Do-It-Yourself Web Site.

What I would suggest in a case such as you described, is to have the lines blownout using compressed air. A plumber can and should do this for you.

They would disconnect all the exisiting gas appliances. Cap all the lines except two. The main line from outside going inside remains opened and one inside line, which is the furthest from the main line entering the house.

A plumber would than back flush, from the furthest inside line, the lines using an air compressor. Blowing out the gas which remains in the lines to the outside. Once that is completed, he/she would cap the two remaining opened lines used for flushing. Removal of any lines which are accessable and if desired or needed, etc. for the prep to install all electric appliances.

Once the air flushing is done, no residual gas will be left behind inside the house. The outside supply line, depending upon how it is installed, above and or below ground, should not pose any problems once the tank is removed.

However, the propane supplier may or may not remove the supply lines during tank removal. Discuss that aspect with the propane supplier or the plumber whom is air flushing out the house lines.

Not likely any of the above is nor suggested as a do it yourself project, if you're not familar with the processes involved. Licenses to do such may be required, depending upon your location, city, county and or state, etc.

Since there is a health condition involved, best to hire a professional. Also because you mentioned the house is otherwise perfect. Worth the additional investment during the entire conversion process, in my opinion. A "Happy & Healthy" wife is another important consideration...:)

I might also suggest that because gas stoves are usually unvented, the products of combustion may be permeating the house rather than a gas leak.

I grew up with a gas stove and became use to it but now when I visit my mom and dad I can detect an odor from the flame, even though the burners are adjusted to peak efficiency.

Perhaps the stove has a standing pilot light that is burning all the time or the water heater or other appliance is spilling fumes.