Is this a submersible pump or above ground pump? Drilled or driven well? How deep is the well? If above ground, are there one or two pipes going into the well?
For an above ground pump (either one- or two-pipe) there is a foot valve (check valve) at the very bottom of the pipe, and replacing it requires you to remove the entire pipe from the well.
Single-pipe above ground pump: you may be able to put a check valve in the pipe between the well and the pump. (These wells have a practical maximum depth of about 25 feet.)
Dual-pipe above ground pump: you must replace the foot valve. You cannot put a check valve between the venturi (at the bottom of the well) and the pump.
If you have a submersible pump, you'll have to pull the pipe & pump out of the well. The check valve usually attaches directly above the pump.
You should not have a check valve between the pressure switch and the pressure tank.
Bottom line: unless you have a shallow well above-ground pump, you'll have to pull the pipe and/or pump out of the well to do the job properly. This may require the services of a crane truck. For a 200' deep well with a 5hp submersible pump and 1-1/4" galvanized steel pipe full of water, the weight can be several hundred pounds. Be very careful you don't drop the pipe/pump in the well; you may not be able to get it out and that means you have to drill a new well.
Take a gander at this Popular Mechanics article on how well pumps work: http://www.popularmechanics.com/home...umbing/1275136
Last edited by Fencepost; 11-05-2010 at 12:39 AM.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.