Another Chapter on Pitless Adapters
As I write these columns and think about different subjects, I seem to have more to say about certain procedures and products used in our industry than others. In our part of the country, cable tool drilling is not at all popular for domestic or commercial wells anymore. This is not to say that it is not used, but it is used far, far less than it was years ago. So I have written about cable tool and am always glad to talk about it. Indeed, I have received a number of calls and letters from drillers who wanted to talk cable tool and I may, perhaps, write an article in the future on this subject. But some things are still being used everyday and these include, but are not limited to, submersible pumps, tanks, well screens and many other items. Writing about these things is, frankly, a more fertile field for the writer, especially if he happens to like them. This article is about one of my favorite subjects, as you may have guessed, the pitless adapter. This time I will concentrate on a very popular type of pitless in 2015, the clamp on.
I have described pitless installation in previous articles and you will recall it is necessary to dig into the earth a number of feet depending on the bury depth, cut the casing below the frost line and either thread a metal casing or glue on a threaded adapter for non-metallic casing. A commercially built pitless adapter is then threaded on with the bury depth selected when the pitless was purchased. Now this all works very well, but there is one downside: The installer is left with a short section of casing, which, would be 3 to 6 feet long, since the pitless takes this section’s place. So, over time, the contractor ends up with a large pile of these short sections of pipe. Occasionally these can be used on another well, but most of the time they are just scrap. Now some of you may be saying, “Why not, if the casing pipe is steel, weld a group of these sections together and make an 18- or 21-foot length of casing?” This is looked down upon in our state well code and, while one is not restricted from using short sections in the completion of a well, a “joint” made up of small welded lengths would be a bad idea. So the pump installer ends up with, in effect, a scrap pile of short sections of pipe.
Many years ago, a local health department in the far north of Michigan decided that each well should have a serial number. Upon completing a well, the driller was required to add a locked metal strip something like what one might see on an electrical power meter. The idea was that every well was identified and a sanitarian could walk up to it, get the ID number and determine exactly what this well was as it was recorded in the well record. A problem arose, however, in that drillers in that part of the state were quite often not the pump installer, so when it was time to install the pump, the PI cut the top of the casing off, installed a pitless adapter, threw the top piece of the casing with the ID tag onto his truck and took it back to his shop — so much for a good idea that did not work out. I don’t know if this local HD still requires this, but I was told that this was the situation by a good driller from that area who is now “drilling” where there are no boulders or dry holes.
The clamp-on pitless came on the scene around here in the late 1960s, when we were all still using steel casing. One of the things it did was to eliminate the short piece of pipe problem. The clamp-on is much like any pitless adapter in that it discharges water from the well below the frost line and still allows easy access to the pump, screen or what have you that is inside the casing.
Most clamp ons come as a kit, which includes four parts.
- An outer casting or assembly that is clamped to the outside of the casing. This part has a gasket of some type, usually an O ring, that, when pulled tight against the casing, makes a water-tight joint. This gasket is designed for a specific casing size so the kit must be purchased for the well size — that is a 4-inch for a 4-inch well, 5-inch for a 5-inch well and so on. A U bolt that fits snugly around the casing is then tightened to the outer assembly. If the kit is for a PVC casing, it will include a curved plate that goes between the U bolt and the casing so tightening will not crush the more fragile plastic material. This outer assembly is tapped with female IPS threads.
- The kit also includes an inner section, usually called the body, which also contains a gasket to make a water-tight joint on the inside of the casing, again, usually an O ring type. This body is tapped at the top for a hanger pipe and at the bottom for the drop pipe. Nearly all the hanger pipe tappings I have seen are 1 inch, but the drop pipe can be 1 inch, 1¼ inches, 2 inches or what have you.
- The third member of the kit is a support plate or bar, which suspends the inner body the correct distance from the top of the casing.
- And the fourth is a well cap.
To make the kit into a useable unit, the installer selects a piece of pipe that conforms to the bury depth. I’ve always used galvanized steel pipe for this “hanger” pipe, but several of my friends have been successful using schedule 80 PVC pipe. To install this type of pitless, the installer needs to rather carefully measure the distance from the support bar or plate to the center of the internal O ring. He then drills a 1- or 1¼-inch hole through the casing, and this needs to be exactly centered. I have heard of people drilling the casing with a drill bit as small as ½ inches, but I don’t think this is recommended by the manufacturers. If the measurements are correct, the internal O ring will be centered around this hole in a vertical direction. The installer then rotates the internal part so that the internal O ring is lined up side-to-side with this hole. The holding plate or bar then gets marked for future reference. This all sounds pretty complicated, but in reality is fairly simple.
The outer assembly is then tightened to the casing with its O ring exactly centered to the hole drilled in the casing. The service pipe can then be attached to this outer assembly and, after adding a feed wire if a submersible pump is used, the underground portion of the installation is done.
If I have rattled on with too many details I apologize. I hope I did not confuse you with a too detailed description. The fourth part of the kit is a well cap and I will write about that and clamp-on pitlesses as general in my next column.
This is written just a few days before Christmas and, here in Michigan, it has been unseasonably warm. We had several days of 60-degree temperatures recently. We have absolutely no snow on the ground. I understand that there is no snow even in northern Michigan. Hope your 2016 is off to a safe and prosperous start.